@@ -1,7651 +0,0 @@
1−use std::collections::{HashMap, HashSet};
2−use std::path::{Path, PathBuf};
3−use std::rc::Rc;
4−
5−use crate::ast::*;
6−use crate::diagnostic::code;
7−pub use crate::diagnostic::{Diagnostic, Severity};
8−use crate::interp::{self, Sink};
9−use crate::syntax::{self, DirectiveArgs, LetForm, NodeKind, Segment, Tree};
10−use crate::value::{self, Value};
11−
12−// ---------------------------------------------------------------------------
13−// Public types
14−// ---------------------------------------------------------------------------
15−
16−pub struct ParseResult {
17− pub document: Document,
18− pub diagnostics: Vec<Diagnostic>,
19− pub included_files: Vec<PathBuf>,
20−}
21−
22−/// An error that stops one line from being evaluated.
23−type ParseError = Diagnostic;
24−
25−// ---------------------------------------------------------------------------
26−// Internal types
27−// ---------------------------------------------------------------------------
28−
29−#[derive(Clone)]
30−struct FnDef {
31− /// The parameters in the order they are declared; one without a
32− /// default is required.
33− params: Vec<syntax::Param>,
34− /// The definition's line and its text (when it is one physical line),
35− /// and its node, for diagnostics about a default.
36− line: usize,
37− source: Option<String>,
38− node: usize,
39− body: Vec<syntax::Node>,
40− /// The file it is defined in, when that isn't the file being compiled
41− /// (see `ParseContext::current_file`).
42− file: Option<String>,
43− /// The slots its body declares (`@slot NAME`), in order.
44− slots: Vec<String>,
45− /// Whether its body has a `@children` for the content of a call.
46− has_children: bool,
47− /// Its scoped `@style`: its class (`hl-fn-NAME-HASH`), and the
48− /// stylesheet nested under it, written into the page once the function
49− /// is called (see `Document::scoped_css`).
50− scoped: Option<(String, String)>,
51− /// What was visible where it was defined: its body and its defaults
52− /// see this, plus its parameters.
53− env: Env,
54− /// It is named like a built-in element and its body calls that name
55− /// outside any `@if`, meaning the element (`@let @nav` around `@nav`):
56− /// it would call itself forever, so a call writes nothing (the
57− /// definition's error says so).
58− wraps_itself: bool,
59−}
60−
61−impl FnDef {
62− fn is_param(&self, name: &str) -> bool {
63− self.params.iter().any(|p| p.name == name)
64− }
65−}
66−
67−/// What a name means: every `@let`, parameter, loop variable and `@data`
68−/// binds one, and they share one namespace.
69−#[derive(Clone)]
70−enum Binding {
71− Value(Value),
72− Bundle(Rc<Vec<Attribute>>),
73− Function(Rc<FnDef>),
74−}
75−
76−/// The names visible at a line: one frame per block it is in (the
77−/// standard library, the file, an element's children, an `@if` branch, an
78−/// iteration of `@each`, a function's body), the innermost last. A
79−/// definition goes into the innermost frame, so it is visible from its
80−/// line to the end of its block. A function keeps the frames visible
81−/// where it is defined; a frame is shared until one side changes it.
82−#[derive(Clone, Default)]
83−struct Env {
84− frames: Vec<Rc<HashMap<String, Binding>>>,
85−}
86−
87−impl Env {
88− fn push(&mut self) {
89− self.frames.push(Rc::default());
90− }
91−
92− fn pop(&mut self) {
93− self.frames.pop();
94− }
95−
96− /// Give `name` a meaning in the innermost frame, replacing what it
97− /// meant there and hiding what it means outside it.
98− fn define(&mut self, name: &str, binding: Binding) {
99− if self.frames.is_empty() {
100− self.push();
101− }
102− if let Some(frame) = self.frames.last_mut() {
103− Rc::make_mut(frame).insert(name.to_string(), binding);
104− }
105− }
106−
107− /// What `name` means here: the innermost definition.
108− fn get(&self, name: &str) -> Option<&Binding> {
109− self.frames.iter().rev().find_map(|frame| frame.get(name))
110− }
111−
112− fn value(&self, name: &str) -> Option<&Value> {
113− match self.get(name)? {
114− Binding::Value(value) => Some(value),
115− _ => None,
116− }
117− }
118−
119− fn bundle(&self, name: &str) -> Option<&Rc<Vec<Attribute>>> {
120− match self.get(name)? {
121− Binding::Bundle(attrs) => Some(attrs),
122− _ => None,
123− }
124− }
125−
126− fn function(&self, name: &str) -> Option<&Rc<FnDef>> {
127− match self.get(name)? {
128− Binding::Function(function) => Some(function),
129− _ => None,
130− }
131− }
132−
133− /// Every name visible here, with what it means.
134− fn visible(&self) -> HashMap<&str, &Binding> {
135− let mut names = HashMap::new();
136− for frame in &self.frames {
137− for (name, binding) in frame.iter() {
138− names.insert(name.as_str(), binding);
139− }
140− }
141− names
142− }
143−
144− /// The names of the values visible here.
145− fn value_names(&self) -> Vec<&str> {
146− self.visible()
147− .into_iter()
148− .filter(|(_, binding)| matches!(binding, Binding::Value(_)))
149− .map(|(name, _)| name)
150− .collect()
151− }
152−
153− /// The names of the bundles visible here.
154− fn bundle_names(&self) -> Vec<&str> {
155− self.visible()
156− .into_iter()
157− .filter(|(_, binding)| matches!(binding, Binding::Bundle(_)))
158− .map(|(name, _)| name)
159− .collect()
160− }
161−}
162−
163−impl interp::Scope for Env {
164− fn get(&self, name: &str) -> Option<Value> {
165− self.value(name).cloned()
166− }
167−}
168−
169−struct ParseContext {
170− /// Source line currently being parsed, for diagnostics raised deep
171− /// inside helpers that don't take a line number.
172− current_line: usize,
173− /// What the `@page` said, once one has run
174− page: Option<Page>,
175− /// Where that `@page` is, for the error a second one gets
176− page_at: Option<String>,
177− meta_tags: Vec<(String, String)>,
178− head_blocks: Vec<String>,
179− /// The first `@meta` or `@head` that ran, for the warning a file
180− /// without `@page` gets: a fragment has no `<head>` for them.
181− head_at: Option<usize>,
182− /// What each name means at the line being evaluated.
183− env: Env,
184− /// Every function whose definition ran, by name (the last one), for
185− /// the checks of code that never runs.
186− defined_functions: HashMap<String, Rc<FnDef>>,
187− css_vars: Vec<(String, String)>,
188− custom_css: Vec<String>,
189− /// The scoped `@style` of each function called so far
190− scoped_css: Vec<String>,
191− og_tags: Vec<(String, String)>,
192− diagnostics: Vec<Diagnostic>,
193− base_path: Option<PathBuf>,
194− included_files: Vec<PathBuf>,
195− include_stack: Vec<PathBuf>,
196− fn_call_stack: Vec<String>,
197− file_cache: HashMap<PathBuf, String>,
198− /// Track which @let variables are referenced (for unused warnings)
199− used_variables: HashSet<String>,
200− /// Track which functions are called (for unused warnings)
201− used_functions: HashSet<String>,
202− /// Track which attribute bundles are referenced (for unused warnings)
203− used_defines: HashSet<String>,
204− /// Line numbers of @let definitions (name -> line)
205− let_lines: HashMap<String, usize>,
206− /// Line numbers of function definitions (name -> line)
207− fn_lines: HashMap<String, usize>,
208− /// Line numbers of attribute bundle definitions (name -> line)
209− define_lines: HashMap<String, usize>,
210− /// Syntax nodes evaluated at least once, by id.
211− visited: HashSet<usize>,
212− /// The id the next parsed tree starts at, so ids are unique across
213− /// the file, its includes and the standard library.
214− next_id: usize,
215− /// The file's tree and those of the files it includes, with the
216− /// include chain that leads to each, for the checks of code that never
217− /// runs.
218− trees: Vec<(Rc<Tree>, Option<String>)>,
219− /// The files each `@include` line brought in (by the line's node id),
220− /// with the include chain that leads to each, so the checks of
221− /// `@slot` and `@children` see an included file's lines where the
222− /// `@include` is written.
223− included_by: Rc<IncludedBy>,
224− /// Every function defined anywhere in the file or the files it
225− /// includes, whether or not its definition runs.
226− namespace: HashSet<String>,
227− /// The line being evaluated, and its text as written when it is one
228− /// physical line, for diagnostics that point at a column.
229− current_source: (usize, Option<String>),
230− /// Variable diagnostics already reported, so a line evaluated many
231− /// times (in a loop, in a function) reports each problem once.
232− /// Keyed by the syntax node (ids are unique across files), line,
233− /// column and message.
234− reported: HashSet<(usize, usize, Option<usize>, String)>,
235− /// The id of the syntax node being evaluated.
236− current_node: usize,
237− /// The file whose lines are being evaluated, when it isn't the file
238− /// being compiled: the standard library, or an included file (by its
239− /// include chain).
240− current_file: Option<String>,
241− /// A call went deeper than [`MAX_CALL_DEPTH`]: the calls it is nested
242− /// in expand to nothing, until the outermost one returns.
243− too_deep: bool,
244− /// A bundle's attributes are being read: a name that could be a
245− /// parameter of the function the bundle is passed to is checked where
246− /// the bundle is used instead.
247− in_bundle: bool,
248− /// `@page`'s attributes are being read: a name close to `favicon` is
249− /// a misspelled word of `@page`'s.
250− in_page: bool,
251−}
252−
253−/// How deeply function calls may nest, so that a function that calls
254−/// itself without an `@if` that stops it is an error instead of a hang.
255−const MAX_CALL_DEPTH: usize = 64;
256−
257−/// A CSS rule at the top level of a stylesheet that starts with `&`
258−/// (outside any `{}`, strings and comments).
259−fn has_top_level_ampersand(css: &str) -> bool {
260− let mut depth = 0usize;
261− let mut chars = css.chars().peekable();
262− let mut at_rule_start = true;
263− while let Some(c) = chars.next() {
264− match c {
265− '/' if chars.peek() == Some(&'*') => {
266− chars.next();
267− let mut last = ' ';
268− for c in chars.by_ref() {
269− if last == '*' && c == '/' {
270− break;
271− }
272− last = c;
273− }
274− continue;
275− }
276− '"' | '\'' => {
277− for d in chars.by_ref() {
278− if d == c {
279− break;
280− }
281− }
282− }
283− '{' => depth += 1,
284− '}' => depth = depth.saturating_sub(1),
285− '&' if depth == 0 && at_rule_start => return true,
286− _ => {}
287− }
288− at_rule_start = match c {
289− '{' | '}' | ';' => true,
290− c if c.is_whitespace() => at_rule_start,
291− _ => false,
292− };
293− }
294− false
295−}
296−
297−/// Whether a file is a library (see [`Tree::is_library`]), with the files
298−/// its `@include` lines name read relative to `base`.
299−fn is_library_file(
300− tree: &Tree,
301− base: Option<&Path>,
302− ctx: &mut ParseContext,
303− seen: &mut Vec<PathBuf>,
304−) -> bool {
305− tree.is_library_with(&mut |path| {
306− if path.contains('$') {
307− return false;
308− }
309− let resolved = base.map_or_else(|| PathBuf::from(path), |base| base.join(path));
310− if seen.contains(&resolved) {
311− return false;
312− }
313− seen.push(resolved.clone());
314− let Ok(text) = ctx.read_file(&resolved) else {
315− return false;
316− };
317− let included = syntax::parse(&text);
318− is_library_file(&included, resolved.parent(), ctx, seen)
319− })
320−}
321−
322−/// The frames around the file's top level: the standard library's and
323−/// the file's own (see [`load_prelude`]).
324−const FILE_FRAMES: usize = 2;
325−
326−/// Evaluates a syntax tree (see `syntax.rs`) into the document's nodes.
327−struct Evaluator;
328−
329−impl ParseContext {
330− /// Bind a value to `name` in the innermost block.
331− fn bind(&mut self, name: &str, value: Value) {
332− self.env.define(name, Binding::Value(value));
333− }
334−
335− /// Evaluate an expression (see `expr.rs`) written at `line` and
336− /// `column` (when known), reporting its errors there.
337− fn eval(
338− &mut self,
339− src: &str,
340− line: usize,
341− column: Option<usize>,
342− ) -> Option<crate::expr::Value> {
343− track_var_refs(src, &mut self.used_variables);
344− match crate::expr::eval(src, &self.env) {
345− Ok(value) => Some(value),
346− Err(error) => {
347− // Without the line to point into, show the expression
348− let shown = matches!(&self.current_source, (current, Some(_)) if *current == line);
349− let before = self.diagnostics.len();
350− self.report(error.at(0), line, column);
351− if !shown && let Some(diagnostic) = self.diagnostics.get_mut(before) {
352− diagnostic.source_line = Some(src.into());
353− }
354− None
355− }
356− }
357− }
358−
359− /// Evaluate a condition; an invalid one is reported and counts as false.
360− fn condition(&mut self, src: &str, line: usize, column: Option<usize>) -> bool {
361− self.eval(src, line, column)
362− .is_some_and(|value| value.truthy())
363− }
364−
365− /// Fill in one slot of htmlang text written at `line` and `column`
366− /// (when known), for `sink`: its escapes stand for themselves and its
367− /// variables are filled in (see `interp.rs`). What can't be filled is
368− /// left as written and reported; the flag says whether everything was
369− /// filled.
370− fn fill(
371− &mut self,
372− raw: &str,
373− line: usize,
374− column: Option<usize>,
375− sink: Sink,
376− ) -> (String, bool) {
377− let (filled, ok) = self.fill_protected(raw, line, column, sink);
378− (restore_escapes(&filled), ok)
379− }
380−
381− /// [`fill`](Self::fill) for text.
382− fn interpolate_text(&mut self, raw: &str, line: usize, column: Option<usize>) -> String {
383− self.fill(raw, line, column, Sink::Text).0
384− }
385−
386− /// [`fill`](Self::fill), with the escapes still placeholders (see
387− /// [`protect_escapes`]).
388− fn fill_protected(
389− &mut self,
390− raw: &str,
391− line: usize,
392− column: Option<usize>,
393− sink: Sink,
394− ) -> (String, bool) {
395− let mut protected = protect_escapes(raw);
396− if sink == Sink::Css {
397− protected = keep_css_string_escapes(&protected);
398− }
399− if !protected.contains('$') {
400− return (protected, true);
401− }
402− track_var_refs(&protected, &mut self.used_variables);
403− let (out, problems) = interp::interpolate_for(&protected, &self.env, sink);
404− let filled = problems.is_empty();
405− for mut problem in problems {
406− match &mut problem {
407− interp::Problem::Undefined { offset, .. }
408− | interp::Problem::CustomProperty { offset, .. }
409− | interp::Problem::Invalid { offset, .. }
410− | interp::Problem::Record { offset, .. } => {
411− // An offset into the protected text, as one into `raw`
412− *offset = protected[..*offset]
413− .chars()
414− .map(|c| escape_of(c).map_or(c.len_utf8(), str::len))
415− .sum();
416− }
417− }
418− self.report(problem, line, column);
419− }
420− (out, filled)
421− }
422−
423− /// Fill in a value slot (an attribute's value, a `@let` value, `@meta`'s
424− /// value) for `sink`, and say whether it is quoted text: one `"..."`, or
425− /// one variable that holds quoted text. Quoted text keeps its quotes
426− /// only in CSS.
427− fn fill_value(
428− &mut self,
429− raw: &str,
430− line: usize,
431− column: Option<usize>,
432− sink: Sink,
433− ) -> (String, Option<Quoted>, bool) {
434− if let Some(inner) = syntax::quoted_string(raw) {
435− let (css, ok) = self.fill(raw, line, column, Sink::Css);
436− // Already reported by the CSS pass, so filled in quietly
437− let (text, _) = interp::interpolate(&protect_escapes(inner), &self.env);
438− let quoted = Quoted {
439− text: restore_escapes(&text),
440− css,
441− };
442− let out = match sink {
443− Sink::Css => quoted.css.clone(),
444− Sink::Text => quoted.text.clone(),
445− };
446− return (out, Some(quoted), ok);
447− }
448− let (out, ok) = self.fill(raw, line, column, sink);
449− let quoted = whole_reference(raw, &self.env).and_then(|path| {
450− match interp::resolve(&path, &self.env)? {
451− Value::Quoted(quoted) => Some(quoted),
452− _ => None,
453− }
454− });
455− (out, quoted, ok)
456− }
457−
458− /// The value of a value slot (a `@let` value, the source of `@each`, a
459− /// parameter's value or default), written at `line` and `column`:
460− ///
461− /// - exactly one `$name` or `${...}` is the value it holds or gives,
462− /// whatever its type (a list, a record, quoted text);
463− /// - one `"..."` is quoted text;
464− /// - commas outside quotes, brackets and `${...}`, and not escaped
465− /// (`\,`), make a list, which prints as written;
466− /// - `A..B` or `A..B step N` with whole numbers is a range;
467− /// - anything else is text, with its variables filled in.
468− ///
469− /// What can't be filled in is reported; the flag says whether
470− /// everything was.
471− fn slot_value(&mut self, raw: &str, line: usize, column: Option<usize>) -> (Value, bool) {
472− let trimmed = raw.trim();
473− let column = column.map(|c| c + (raw.len() - raw.trim_start().len()));
474− if let Some(value) = self.whole_value(trimmed, line, column) {
475− return value;
476− }
477− if syntax::quoted_string(trimmed).is_some() {
478− let (text, quoted, ok) = self.fill_value(trimmed, line, column, Sink::Text);
479− return (quoted.map_or(Value::Str(text), Value::Quoted), ok);
480− }
481− let parts = syntax::split_list(trimmed);
482− if parts.len() > 1 {
483− // Each item is a value of its own; the list prints as written
484− let mut items = Vec::new();
485− let mut written = String::new();
486− let mut ok = true;
487− let mut end = 0;
488− for part in parts {
489− let item = &trimmed[part.clone()];
490− let lead = item.len() - item.trim_start().len();
491− written.push_str(&trimmed[end..part.start + lead]);
492− end = part.start + lead + item.trim().len();
493− if item.trim().is_empty() {
494− continue;
495− }
496− let at = column.map(|c| c + part.start + lead);
497− let (value, text, filled) = self.item_value(item.trim(), line, at);
498− ok &= filled;
499− written.push_str(&text);
500− items.push(value);
501− }
502− written.push_str(&trimmed[end..]);
503− let list = value::List {
504− items: Rc::new(items),
505− written: Some(written.into()),
506− };
507− return (Value::List(list), ok);
508− }
509− let (text, ok) = self.fill(trimmed, line, column, Sink::Text);
510− match value::written_range(&text) {
511− Some(Ok(range)) => (range, ok),
512− Some(Err(message)) => {
513− self.report(
514− interp::Problem::Invalid { message, offset: 0 },
515− line,
516− column,
517− );
518− (Value::list(Vec::new()), false)
519− }
520− None => (Value::Str(text), ok),
521− }
522− }
523−
524− /// An item of a list written in the source (see
525− /// [`slot_value`](Self::slot_value)), and how it is written in the
526− /// list's text.
527− fn item_value(
528− &mut self,
529− item: &str,
530− line: usize,
531− column: Option<usize>,
532− ) -> (Value, String, bool) {
533− let (value, ok) = match self.whole_value(item, line, column) {
534− Some(value) => value,
535− None if syntax::quoted_string(item).is_some() => {
536− let (text, quoted, ok) = self.fill_value(item, line, column, Sink::Text);
537− (quoted.map_or(Value::Str(text), Value::Quoted), ok)
538− }
539− None => {
540− let (text, ok) = self.fill(item, line, column, Sink::Text);
541− (Value::Str(text), ok)
542− }
543− };
544− // Quoted text keeps its quotes in the list's text, as written
545− let text = value
546− .quoted_css()
547− .map_or_else(|| value.to_string(), str::to_string);
548− (value, text, ok)
549− }
550−
551− /// The value of a slot that is exactly one `$name` or `${...}`, with its
552− /// type; `None` when it is anything else.
553− fn whole_value(
554− &mut self,
555− raw: &str,
556− line: usize,
557− column: Option<usize>,
558− ) -> Option<(Value, bool)> {
559− let after = raw.strip_prefix('$')?;
560− let (reference, len) = interp::reference(after, &self.env)?;
561− if len != after.len() {
562− return None;
563− }
564− track_var_refs(raw, &mut self.used_variables);
565− let problem = match reference {
566− interp::Reference::Var(path) => match interp::resolve(&path, &self.env) {
567− Some(value) => return Some((value, true)),
568− None => interp::Problem::Undefined {
569− name: path,
570− offset: 0,
571− },
572− },
573− interp::Reference::Expr(source) => match crate::expr::eval(source, &self.env) {
574− Ok(value) => return Some((value, true)),
575− Err(crate::expr::Error::Invalid(message)) => {
576− interp::Problem::Invalid { message, offset: 0 }
577− }
578− Err(error) => error.at(2),
579− },
580− };
581− self.report(problem, line, column);
582− Some((Value::Str(raw.to_string()), false))
583− }
584−
585− /// Report a variable that can't be filled in, or an invalid `${...}`,
586− /// at `offset` from `column`.
587− fn report(&mut self, problem: interp::Problem, line: usize, column: Option<usize>) {
588− let (line_text, column) = match &self.current_source {
589− // The column is only shown with the line it points into
590− (current, Some(text)) if *current == line => (Some(text.clone()), column),
591− _ => (None, None),
592− };
593− let diagnostic = match problem {
594− interp::Problem::Undefined { name, offset } => {
595− let column = column.map(|c| c + offset);
596− let mut diagnostic = self.undefined(&name, line);
597− if let Some(column) = column {
598− diagnostic = diagnostic.column(column);
599− }
600− diagnostic
601− }
602− interp::Problem::Invalid { message, offset } => {
603− let diagnostic = Diagnostic::error(
604− code::INVALID_EXPRESSION,
605− line,
606− format!("invalid expression: {}", message),
607− );
608− match column {
609− Some(column) => diagnostic.column(column + offset),
610− None => diagnostic,
611− }
612− }
613− interp::Problem::CustomProperty { name, offset } => {
614− let diagnostic = Diagnostic::error(
615− code::INVALID_VALUE,
616− line,
617− interp::custom_property_message(&name),
618− )
619− .subject(format!("${}", name))
620− .suggest(Some(format!("var({})", name)));
621− match column {
622− Some(column) => diagnostic.column(column + offset),
623− None => diagnostic,
624− }
625− }
626− interp::Problem::Record { message, offset } => {
627− let diagnostic = Diagnostic::error(code::INVALID_VALUE, line, message);
628− match column {
629− Some(column) => diagnostic.column(column + offset),
630− None => diagnostic,
631− }
632− }
633− };
634− let diagnostic = match line_text {
635− Some(text) => diagnostic.source(text),
636− None => diagnostic,
637− };
638− self.push_once(diagnostic);
639− }
640−
641− /// Report a diagnostic unless the node being evaluated already did,
642− /// so a line evaluated many times (in a loop, in a function) reports
643− /// each problem once.
644− fn push_once(&mut self, diagnostic: Diagnostic) {
645− let key = (
646− self.current_node,
647− diagnostic.line,
648− diagnostic.column,
649− diagnostic.message.clone(),
650− );
651− if self.reported.insert(key) {
652− self.diagnostics.push(diagnostic);
653− }
654− }
655−
656− /// The error for `$name` with no definition: what the name is if it is
657− /// something else, or the closest defined name.
658− fn undefined(&mut self, name: &str, line: usize) -> Diagnostic {
659− if self.env.bundle(name).is_some() {
660− // Reported here, so not also as unused
661− self.used_defines.insert(name.to_string());
662− return Diagnostic::error(
663− code::UNDEFINED_VARIABLE,
664− line,
665− format!(
666− "'${}' is an attribute bundle, not a value: it goes in an attribute list \
667− as a whole attribute, `[${}]`",
668− name, name
669− ),
670− )
671− .subject(name);
672− }
673− if self.env.function(name).is_some() {
674− self.used_functions.insert(name.to_string());
675− return Diagnostic::error(
676− code::UNDEFINED_VARIABLE,
677− line,
678− format!(
679− "'${}' is a function, not a value: it is called as an element, `@{}`",
680− name, name
681− ),
682− )
683− .subject(name);
684− }
685− // `$i-label` where `$i` is defined: a `-` joins a name
686− if let Some((defined, rest)) = name
687− .match_indices('-')
688− .map(|(i, _)| (&name[..i], &name[i..]))
689− .find(|(before, _)| self.env.value(before).is_some())
690− {
691− return Diagnostic::error(
692− code::UNDEFINED_VARIABLE,
693− line,
694− format!(
695− "undefined variable '${}': a `-` is part of a name. For '${}' followed \
696− by '{}', write `${{{}}}{}`",
697− name, defined, rest, defined, rest
698− ),
699− )
700− .subject(name);
701− }
702− let suggestion = suggest_var_name(name, &self.env.value_names());
703− let message = match (&suggestion, self.let_lines.get(name)) {
704− (Some(closest), _) => format!(
705− "undefined variable '${}', did you mean '${}'?",
706− name, closest
707− ),
708− // Defined, but not where this line can see it
709− (None, Some(_)) => format!(
710− "undefined variable '${}': a `@let` defines it, but not where this line \
711− can see it. A definition is visible from its line to the end of its \
712− block, and a function's body sees what is defined above the function",
713− name
714− ),
715− (None, None) => format!("undefined variable '${}'", name),
716− };
717− Diagnostic::error(code::UNDEFINED_VARIABLE, line, message)
718− .subject(name)
719− .suggest(suggestion)
720− }
721−
722− /// Note the node being evaluated, for diagnostics.
723− fn enter(&mut self, node: &syntax::Node) {
724− self.current_line = node.span.line;
725− self.current_node = node.id;
726− let text =
727− (node.line_count <= 1).then(|| format!("{}{}", " ".repeat(node.indent), node.source));
728− self.current_source = (node.span.line, text);
729− }
730−
731− /// Parse a file's text into a tree whose ids don't clash with the
732− /// trees parsed before it.
733− fn parse_tree(&mut self, text: &str) -> Rc<Tree> {
734− let tree = syntax::parse_from(text, self.next_id);
735− self.next_id = tree.end_id;
736− Rc::new(tree)
737− }
738−
739− /// Read a file (once), relative to the current file.
740− fn read_file(&mut self, resolved: &Path) -> std::io::Result<String> {
741− if let Some(cached) = self.file_cache.get(resolved) {
742− return Ok(cached.clone());
743− }
744− let text = std::fs::read_to_string(resolved)?;
745− self.file_cache.insert(resolved.to_path_buf(), text.clone());
746− Ok(text)
747− }
748−
749− fn resolve(&self, filename: &str) -> PathBuf {
750− match &self.base_path {
751− Some(base) => base.join(filename),
752− None => PathBuf::from(filename),
753− }
754− }
755−}
756−
757−/// The standard library (`std.hl`): components and bundles defined in
758−/// htmlang itself and available in every file.
759−const PRELUDE: &str = include_str!("std.hl");
760−
761−fn load_prelude(ctx: &mut ParseContext) {
762− // The library's definitions are in a block of their own, around the
763− // file's, so the file's own `@let` of the same name hides them
764− ctx.env.push();
765− let tree = ctx.parse_tree(PRELUDE);
766− collect_namespace(&tree.nodes, None, &mut HashSet::new(), ctx);
767− ctx.current_file = Some("std.hl".to_string());
768− let _ = Evaluator.eval_block(&tree.nodes, ctx);
769− ctx.current_file = None;
770− // Library definitions aren't the file's own: never report them unused.
771− ctx.fn_lines.clear();
772− ctx.define_lines.clear();
773− ctx.let_lines.clear();
774− ctx.env.push();
775−}
776−
777−pub fn parse(input: &str) -> ParseResult {
778− parse_with_base(input, None)
779−}
780−
781−pub fn parse_with_base(input: &str, base_path: Option<&Path>) -> ParseResult {
782− let mut ctx = ParseContext {
783− current_line: 0,
784− page: None,
785− page_at: None,
786− meta_tags: Vec::new(),
787− head_blocks: Vec::new(),
788− head_at: None,
789− env: Env::default(),
790− defined_functions: HashMap::new(),
791− css_vars: Vec::new(),
792− custom_css: Vec::new(),
793− scoped_css: Vec::new(),
794− og_tags: Vec::new(),
795− diagnostics: Vec::new(),
796− base_path: base_path.map(|p| p.to_path_buf()),
797− included_files: Vec::new(),
798− include_stack: Vec::new(),
799− fn_call_stack: Vec::new(),
800− file_cache: HashMap::new(),
801− used_variables: HashSet::new(),
802− used_functions: HashSet::new(),
803− used_defines: HashSet::new(),
804− let_lines: HashMap::new(),
805− fn_lines: HashMap::new(),
806− define_lines: HashMap::new(),
807− visited: HashSet::new(),
808− next_id: 0,
809− trees: Vec::new(),
810− included_by: Rc::default(),
811− namespace: HashSet::new(),
812− current_source: (0, None),
813− reported: HashSet::new(),
814− current_node: 0,
815− current_file: None,
816− too_deep: false,
817− in_bundle: false,
818− in_page: false,
819− };
820− load_prelude(&mut ctx);
821− let tree = ctx.parse_tree(input);
822− ctx.diagnostics.extend(tree.diagnostics.iter().cloned());
823− ctx.trees.push((tree.clone(), None));
824− collect_namespace(
825− &tree.nodes,
826− base_path.map(Path::to_path_buf),
827− &mut HashSet::new(),
828− &mut ctx,
829− );
830− let nodes = Evaluator.eval_block(&tree.nodes, &mut ctx);
831− check_unevaluated(&mut ctx);
832− check_slot_places(&mut ctx);
833− validate_tree(&nodes, None, false, &mut ctx.diagnostics);
834− // A library's definitions are for the files that include it
835− let library = is_library_file(&tree, base_path, &mut ctx, &mut Vec::new());
836− let exported: HashSet<String> = if library {
837− tree.nodes
838− .iter()
839− .filter_map(|node| match node.directive().map(|d| &d.args) {
840− Some(DirectiveArgs::Let(def)) => Some(def.name.clone()),
841− _ => None,
842− })
843− .collect()
844− } else {
845− HashSet::new()
846− };
847− check_unused(&mut ctx, &exported);
848− if let (None, Some(line)) = (&ctx.page, ctx.head_at)
849− && !library
850− {
851− ctx.diagnostics.push(Diagnostic::warning(
852− code::NO_EFFECT,
853− line,
854− "a file without @page is a fragment, which has no <head>: @meta and @head are \
855− left out of it (give the file a @page, or put them in the page that includes it)"
856− .to_string(),
857− ));
858− }
859− dedupe(&mut ctx.diagnostics);
860− // What the file itself defines at its top level
861− let file = ctx.env.frames.last().cloned().unwrap_or_default();
862− let mut variables = HashMap::new();
863− let mut defines = HashMap::new();
864− for (name, binding) in file.iter() {
865− match binding {
866− Binding::Value(value) => {
867− variables.insert(name.clone(), value.to_string());
868− }
869− Binding::Bundle(attrs) => {
870− defines.insert(name.clone(), attrs.to_vec());
871− }
872− Binding::Function(_) => {}
873− }
874− }
875− ParseResult {
876− document: Document {
877− page: ctx.page,
878− meta_tags: ctx.meta_tags,
879− head_blocks: ctx.head_blocks,
880− variables,
881− defines,
882− css_vars: ctx.css_vars,
883− custom_css: ctx.custom_css,
884− scoped_css: ctx.scoped_css,
885− og_tags: ctx.og_tags,
886− nodes,
887− },
888− diagnostics: ctx.diagnostics,
889− included_files: ctx.included_files,
890− }
891−}
892−
893−// ---------------------------------------------------------------------------
894−// Code that never runs: an untaken branch, an uncalled function, a loop over
895−// an empty list
896−// ---------------------------------------------------------------------------
897−
898−/// Collect the functions defined anywhere in `nodes` and in the files they
899−/// include (by a literal path), into `ctx.namespace`.
900−fn collect_namespace(
901− nodes: &[syntax::Node],
902− base: Option<PathBuf>,
903− seen: &mut HashSet<PathBuf>,
904− ctx: &mut ParseContext,
905−) {
906− let mut includes = Vec::new();
907− for node in nodes {
908− node.walk(&mut |node| match node.directive().map(|d| &d.args) {
909− Some(DirectiveArgs::Let(def)) if matches!(def.form, LetForm::Function(_)) => {
910− ctx.namespace.insert(def.name.clone());
911− }
912− Some(DirectiveArgs::Text(Some(path))) if node.is_directive("include") => {
913− includes.push(path.raw.clone());
914− }
915− _ => {}
916− });
917− }
918− for path in includes {
919− let path = path.trim_matches('"');
920− if path.contains('$') {
921− continue;
922− }
923− let resolved = match &base {
924− Some(base) => base.join(path),
925− None => PathBuf::from(path),
926− };
927− if !seen.insert(resolved.clone()) {
928− continue;
929− }
930− let Ok(text) = ctx.read_file(&resolved) else {
931− continue;
932− };
933− let tree = syntax::parse(&text);
934− let parent = resolved.parent().map(Path::to_path_buf);
935− collect_namespace(&tree.nodes, parent, seen, ctx);
936− }
937−}
938−
939−/// Check the lines that were never evaluated: element and function names,
940−/// and the attributes of built-in elements (those that don't depend on a
941−/// variable). Names that come from data are only checked when evaluated.
942−fn check_unevaluated(ctx: &mut ParseContext) {
943− let trees = std::mem::take(&mut ctx.trees);
944− let mut seen = HashSet::new();
945− for (tree, chain) in &trees {
946− let before = ctx.diagnostics.len();
947− for node in &tree.nodes {
948− check_unevaluated_node(node, ctx);
949− }
950− let mut found = ctx.diagnostics.split_off(before);
951− if let Some(chain) = chain {
952− for d in &mut found {
953− d.message = format!("{}\n in {}", d.message, chain);
954− }
955− }
956− // A file included twice is checked twice: report each problem once
957− found.retain(|d| seen.insert((d.line, d.message.clone())));
958− ctx.diagnostics.extend(found);
959− }
960− ctx.trees = trees;
961−}
962−
963−fn check_unevaluated_node(node: &syntax::Node, ctx: &mut ParseContext) {
964− if !ctx.visited.contains(&node.id) {
965− let line = node.span.line;
966− // A reference from code that doesn't run still counts as a use
967− track_var_refs(&node.source, &mut ctx.used_variables);
968− let before = ctx.diagnostics.len();
969− match &node.kind {
970− NodeKind::Element(element) => {
971− for head in &element.chain {
972− check_head(head, line, ctx);
973− }
974− check_unevaluated_content(node, element, ctx);
975− if let Some(text) = &element.text {
976− check_inline_heads(text, line, ctx);
977− }
978− }
979− NodeKind::Text(text) => check_inline_heads(text, line, ctx),
980− // `@page`'s attributes are checked like an element's (a layout's
981− // `@page` is in a function that may not run in this file)
982− NodeKind::Directive(syntax::Directive {
983− args:
984− DirectiveArgs::Page {
985− attrs: Some(list), ..
986− },
987− ..
988− }) => {
989− let words: Vec<String> = crate::vocab::PAGE_WORDS
990− .iter()
991− .map(|w| w.to_string())
992− .collect();
993− ctx.in_page = true;
994− check_attrs(&list.attrs, line, ctx, &words);
995− ctx.in_page = false;
996− check_page_tokens(&list.attrs, line, ctx);
997− }
998− _ => {}
999− }
1000− let text = written_line(node);
1001− for d in &mut ctx.diagnostics[before..] {
1002− d.source_line.get_or_insert_with(|| text.as_str().into());
1003− }
1004− }
1005− for child in &node.children {
1006− check_unevaluated_node(child, ctx);
1007− }
1008−}
1009−
1010−/// Check the content passed to the calls of a line that was never
1011−/// evaluated: its `@slot NAME` blocks, and, for a function without
1012−/// `@children`, any other content.
1013−fn check_unevaluated_content(
1014− node: &syntax::Node,
1015− element: &syntax::ElementLine,
1016− ctx: &mut ParseContext,
1017−) {
1018− let calls: Vec<Option<(String, Rc<FnDef>)>> = element
1019− .chain
1020− .iter()
1021− .map(|head| {
1022− let function = ctx.defined_functions.get(&head.name)?;
1023− Some((head.name.clone(), function.clone()))
1024− })
1025− .collect();
1026− check_fillers(node, element, &calls, ctx);
1027− let last = calls.len() - 1;
1028− for (i, call) in calls.iter().enumerate() {
1029− let Some((name, function)) = call else {
1030− continue;
1031− };
1032− if function.has_children || function.wraps_itself {
1033− continue;
1034− }
1035− let content = if i == last {
1036− element.text.is_some() || holds_content(&node.children, ctx)
1037− } else {
1038− element.chain[i + 1].name != "slot" || !slot_is_built_in(ctx)
1039− };
1040− if content {
1041− let head = &element.chain[i];
1042− ctx.push_once(no_children(
1043− name,
1044− node.span.line,
1045− name_column(head, node.span.line),
1046− ));
1047− }
1048− }
1049−}
1050−
1051−/// Check a head that was never evaluated: its name, and its attributes
1052−/// (for a call, see [`check_call`]).
1053−fn check_head(head: &syntax::Head, line: usize, ctx: &mut ParseContext) {
1054− let is_function =
1055− ctx.namespace.contains(&head.name) || ctx.defined_functions.contains_key(&head.name);
1056− if is_function {
1057− ctx.used_functions.insert(head.name.clone());
1058− if let Some(function) = ctx.defined_functions.get(&head.name).cloned()
1059− && !function.wraps_itself
1060− {
1061− check_call(head, &function, line, ctx);
1062− }
1063− return;
1064− }
1065− let kind = match parse_element_kind(&head.name, line, ctx) {
1066− Ok(kind) => kind,
1067− Err(e) => {
1068− ctx.diagnostics.push(e);
1069− return;
1070− }
1071− };
1072− if let Some(list) = &head.attrs {
1073− check_attrs(&list.attrs, line, ctx, &[]);
1074− // A word for laying out children on an element that doesn't lay
1075− // them out, as where the code runs (see `validate_tree`)
1076− if !kind.layout().is_container() && !has_no_element(&kind) {
1077− for attr in &list.attrs {
1078− let base = crate::vocab::base_attribute(&attr.key);
1079− if !attr.html
1080− && attr.choice.is_none()
1081− && attr.prefixed.is_none()
1082− && crate::vocab::CONTAINER_ATTRIBUTES.contains(&base)
1083− && !crate::vocab::split_prefixes(&attr.key)
1084− .0
1085− .contains(&"children:")
1086− {
1087− ctx.push_once(not_a_container(&kind, line, base).column(attr.span.column));
1088− }
1089− }
1090− }
1091− }
1092−}
1093−
1094−/// The attributes of a list that is never evaluated that can be checked
1095−/// together: not bundles or `if()`s. Names are checked; a value with a
1096−/// variable in it depends on what the variable holds, so only a literal
1097−/// value is (the other is checked as an empty value).
1098−/// `@page`'s own rules (see `check_page_attr`) for a list that isn't
1099−/// evaluated, as written: a value made from a variable counts as given.
1100−fn check_page_tokens(tokens: &[syntax::Attr], line: usize, ctx: &mut ParseContext) {
1101− for token in tokens {
1102− match &token.choice {
1103− Some(choice) => {
1104− for branch in &choice.branches {
1105− check_page_tokens(branch.attrs(), line, ctx);
1106− }
1107− }
1108− // Under prefixes there are only styles
1109− None if token.key.starts_with('$') || token.prefixed.is_some() => {}
1110− None => {
1111− let value = token.value.as_deref().map(|v| v.trim_matches('"'));
1112− let value = match value {
1113− Some(v) if v.contains('$') => Some("$"),
1114− other => other,
1115− };
1116− check_page_attr(
1117− &token.key,
1118− token.html,
1119− value,
1120− line,
1121− Some(token.span.column),
1122− ctx,
1123− );
1124− }
1125− }
1126− }
1127−}
1128−
1129−fn literal_attrs(tokens: &[syntax::Attr]) -> Vec<syntax::Attr> {
1130− // A prefixed group is checked with its prefixes, as far as its own
1131− // attributes can be; a prefixed bundle or `if()` depends on what it holds
1132− let group = |a: &syntax::Attr| {
1133− let prefixed = a.prefixed.as_ref()?;
1134− let syntax::Branch::Group { list, trailing } = &prefixed.target else {
1135− return None;
1136− };
1137− let mut list = list.clone();
1138− list.attrs = literal_attrs(&list.attrs);
1139− let mut a = a.clone();
1140− a.prefixed = Some(Box::new(syntax::Prefixed {
1141− target: syntax::Branch::Group {
1142− list,
1143− trailing: trailing.clone(),
1144− },
1145− ..(**prefixed).clone()
1146− }));
1147− Some(a)
1148− };
1149− let groups = tokens.iter().filter_map(group);
1150− tokens
1151− .iter()
1152− .filter(|a| {
1153− let bundle = a.key.starts_with('$') && a.value.is_none() && !a.html;
1154− a.choice.is_none() && a.prefixed.is_none() && !bundle
1155− })
1156− .map(|a| {
1157− let mut a = a.clone();
1158− let variable = |v: &String| v.contains('$');
1159− if !a.key.contains('$') && a.value.as_ref().is_some_and(variable) {
1160− a.value = Some(String::new());
1161− a.raw = format!("{} ", a.key);
1162− }
1163− a
1164− })
1165− .chain(groups)
1166− .collect()
1167−}
1168−
1169−/// Check a call that was never evaluated: how it passes its parameters
1170−/// (none written `name=value`, and every one without a default passed,
1171−/// when no bundle or `if()` could pass it), and its other attributes, like
1172−/// those of an element.
1173−fn check_call(head: &syntax::Head, function: &FnDef, line: usize, ctx: &mut ParseContext) {
1174− let name = head.name.as_str();
1175− let attrs = head.attrs.as_ref().map_or(&[][..], |list| &list.attrs[..]);
1176− written_parameter_forms(name, function, attrs, line, ctx);
1177− if let Some(list) = &head.attrs {
1178− let params: Vec<String> = function.params.iter().map(|p| p.name.clone()).collect();
1179− check_attrs(&list.attrs, line, ctx, ¶ms);
1180− }
1181− let unknown = attrs
1182− .iter()
1183− .any(|a| a.choice.is_some() || (a.key.starts_with('$') && a.value.is_none()));
1184− if unknown {
1185− return;
1186− }
1187− for param in function.params.iter().filter(|p| p.default.is_none()) {
1188− if !attrs.iter().any(|a| a.key == param.name) {
1189− let column = name_column(head, line);
1190− ctx.push_once(missing_parameter(name, ¶m.name, line, column));
1191− }
1192− }
1193−}
1194−
1195−/// Report each parameter a call's list writes `name=value`, with the value
1196−/// as written and its column; returns their names, so the evaluated call
1197−/// doesn't report them again.
1198−fn written_parameter_forms(
1199− name: &str,
1200− function: &FnDef,
1201− attrs: &[syntax::Attr],
1202− line: usize,
1203− ctx: &mut ParseContext,
1204−) -> Vec<String> {
1205− let mut reported = Vec::new();
1206− for attr in attrs {
1207− if !(attr.html && function.is_param(&attr.key)) {
1208− continue;
1209− }
1210− let at = if attr.span.line == 0 {
1211− line
1212− } else {
1213− attr.span.line
1214− };
1215− let value = attr.value.as_deref().unwrap_or("");
1216− let diagnostic = parameter_form(name, &attr.key, value, at).column(attr.span.column);
1217− ctx.push_once(match &ctx.current_source {
1218− (current, Some(text)) if *current == at => diagnostic.source(text.clone()),
1219− _ => diagnostic,
1220− });
1221− reported.push(attr.key.clone());
1222− }
1223− reported
1224−}
1225−
1226−fn check_inline_heads(text: &syntax::Text, line: usize, ctx: &mut ParseContext) {
1227− for segment in &text.segments {
1228− if let Segment::Inline(inline) = segment {
1229− check_head(&inline.head, line, ctx);
1230− if let Some(text) = &inline.text {
1231− check_inline_heads(text, line, ctx);
1232− }
1233− }
1234− }
1235−}
1236−
1237−// ---------------------------------------------------------------------------
1238−// Evaluation
1239−// ---------------------------------------------------------------------------
1240−
1241−/// The `@else` lines that continue the `@if` or `@each` before `from`, and
1242−/// the position after them.
1243−fn else_branches(block: &[syntax::Node], from: usize, is_if: bool) -> (Vec<&syntax::Node>, usize) {
1244− let mut branches = Vec::new();
1245− let mut next = from;
1246− let mut i = from;
1247− while i < block.len() {
1248− let node = &block[i];
1249− i += 1;
1250− if node.is_trivia() {
1251− continue;
1252− }
1253− let condition = match node.directive().map(|d| &d.args) {
1254− Some(DirectiveArgs::Else { condition }) => condition.is_some(),
1255− _ => break,
1256− };
1257− if condition && !is_if {
1258− break;
1259− }
1260− branches.push(node);
1261− next = i;
1262− if !condition {
1263− break;
1264− }
1265− }
1266− (branches, next)
1267−}
1268−
1269−impl Evaluator {
1270− fn eval_block(&mut self, block: &[syntax::Node], ctx: &mut ParseContext) -> Vec<Node> {
1271− let mut nodes = Vec::new();
1272− let mut i = 0;
1273− while i < block.len() {
1274− let node = &block[i];
1275− i += 1;
1276− if node.is_trivia() {
1277− continue;
1278− }
1279− let result = match node.directive().map(|d| d.name()) {
1280− Some(name @ ("if" | "each")) => {
1281− let (branches, next) = else_branches(block, i, name == "if");
1282− i = next;
1283− if name == "if" {
1284− Ok(Some(self.eval_if(node, &branches, ctx)))
1285− } else {
1286− self.eval_each(node, branches.first().copied(), ctx)
1287− }
1288− }
1289− // Reported as a syntax error
1290− Some("else") => {
1291− ctx.visited.insert(node.id);
1292− Ok(None)
1293− }
1294− _ => self.eval(node, ctx),
1295− };
1296− match result {
1297− Ok(Some(new_nodes)) => nodes.extend(new_nodes),
1298− Ok(None) => {}
1299− // Record the error and go on, to report several in one pass
1300− Err(mut e) => {
1301− e.source_line
1302− .get_or_insert_with(|| node.source.as_str().into());
1303− ctx.diagnostics.push(e);
1304− }
1305− }
1306− }
1307− nodes
1308− }
1309−
1310− /// Evaluate a block in its own scope: what it defines is visible to
1311− /// the end of the block, and not after it.
1312− fn eval_scoped(&mut self, block: &[syntax::Node], ctx: &mut ParseContext) -> Vec<Node> {
1313− ctx.env.push();
1314− let nodes = self.eval_block(block, ctx);
1315− ctx.env.pop();
1316− nodes
1317− }
1318−
1319− /// `@if` with its `@else if` / `@else` branches. Every condition is
1320− /// checked (and its errors reported); the first that holds picks the
1321− /// branch.
1322− fn eval_if(
1323− &mut self,
1324− node: &syntax::Node,
1325− branches: &[&syntax::Node],
1326− ctx: &mut ParseContext,
1327− ) -> Vec<Node> {
1328− let mut chosen = None;
1329− for branch in std::iter::once(node).chain(branches.iter().copied()) {
1330− ctx.visited.insert(branch.id);
1331− ctx.enter(branch);
1332− let holds = match branch.directive().map(|d| &d.args) {
1333− Some(DirectiveArgs::Condition(condition))
1334− | Some(DirectiveArgs::Else {
1335− condition: Some(condition),
1336− }) => {
1337− !condition.raw.is_empty()
1338− && ctx.condition(
1339− &condition.raw,
1340− branch.span.line,
1341− Some(condition.span.column),
1342− )
1343− }
1344− Some(DirectiveArgs::Else { condition: None }) => true,
1345− // A syntax error, already reported
1346− _ => false,
1347− };
1348− if holds && chosen.is_none() {
1349− chosen = Some(&branch.children);
1350− }
1351− }
1352− chosen.map_or_else(Vec::new, |body| self.eval_scoped(body, ctx))
1353− }
1354−
1355− fn eval(
1356− &mut self,
1357− node: &syntax::Node,
1358− ctx: &mut ParseContext,
1359− ) -> Result<Option<Vec<Node>>, ParseError> {
1360− ctx.visited.insert(node.id);
1361− ctx.enter(node);
1362− match &node.kind {
1363− NodeKind::Blank | NodeKind::Comment => Ok(None),
1364− // `@code` and `@textarea` show their body as text; `@script`'s
1365− // goes into the page as it is
1366− NodeKind::Verbatim(body) if body.escaped => {
1367− let text = body.text.trim_matches('\n').to_string();
1368− Ok(Some(vec![Node::Text(vec![TextSegment::Plain(text)])]))
1369− }
1370− NodeKind::Verbatim(body) => Ok(Some(vec![Node::Raw(body.text.clone())])),
1371− NodeKind::Directive(directive) => {
1372− let mut nodes = self.eval_directive(node, directive, ctx)?;
1373− // A directive that takes no body: the lines indented under
1374− // it (a syntax error) are evaluated as its siblings. A
1375− // @let's body belongs to it even under a value (also an
1376− // error), so it is never evaluated in place.
1377− let takes_body = directive.spec.body != BodyKind::None;
1378− if !takes_body {
1379− let siblings = self.eval_block(&node.children, ctx);
1380− nodes.get_or_insert_with(Vec::new).extend(siblings);
1381− }
1382− Ok(nodes)
1383− }
1384− NodeKind::Element(element) => self.eval_element(node, element, ctx).map(Some),
1385− NodeKind::Text(text) => {
1386− let mut nodes = vec![Node::Text(text_segments(text, ctx))];
1387− // Text takes no body: lines indented under it are its
1388− // siblings
1389− nodes.extend(self.eval_block(&node.children, ctx));
1390− Ok(Some(nodes))
1391− }
1392− }
1393− }
1394−
1395− fn eval_directive(
1396− &mut self,
1397− node: &syntax::Node,
1398− directive: &syntax::Directive,
1399− ctx: &mut ParseContext,
1400− ) -> Result<Option<Vec<Node>>, ParseError> {
1401− let line_num = node.span.line;
1402− let content = &node.source;
1403− match (directive.name(), &directive.args) {
1404− // @page [lang=en, favicon /f.png, background #f8fafc] Title
1405− ("page", DirectiveArgs::Page { attrs, title }) => {
1406− let page = read_page(attrs.as_ref(), title.as_ref(), line_num, ctx);
1407− // A page has one root: a second `@page` (a layout called
1408− // twice, or one called after the page's own) is an error
1409− let here = match &ctx.current_file {
1410− Some(file) => format!("line {} of {}", line_num, file),
1411− None => format!("line {}", line_num),
1412− };
1413− if let Some(first) = &ctx.page_at {
1414− let again = if *first == here {
1415− "this @page runs a second time (in a loop, or in a function called \
1416− twice)"
1417− .to_string()
1418− } else {
1419− format!("a second @page (this page already has one, on {})", first)
1420− };
1421− let diagnostic = Diagnostic::error(
1422− code::DUPLICATE_PAGE,
1423− line_num,
1424− format!(
1425− "{}: a page has one @page, the root element that styles its <body>",
1426− again
1427− ),
1428− )
1429− .source(content.clone())
1430− .subject("@page");
1431− ctx.diagnostics.push(diagnostic);
1432− } else {
1433− ctx.page_at = Some(here);
1434− ctx.page = Some(page);
1435− }
1436− Ok(None)
1437− }
1438−
1439− ("let", DirectiveArgs::Let(def)) => {
1440− let name = def.name.as_str();
1441− // Values, bundles and functions share one namespace: a
1442− // definition replaces whatever the name meant in its block
1443− match &def.form {
1444− LetForm::Function(function) => {
1445− self.define_function(name, &function.params, node, ctx);
1446− }
1447− // `@let name = EXPR` computes its value (see expr.rs)
1448− LetForm::Computed(expression) => {
1449− let value = ctx
1450− .eval(&expression.raw, line_num, Some(expression.span.column))
1451− .unwrap_or_else(Value::empty);
1452− set_variable(name, value, line_num, ctx);
1453− }
1454− // Attribute bundle: @let name [attr1, attr2, ...]
1455− LetForm::Bundle(list) => {
1456− ctx.in_bundle = true;
1457− let attrs = parse_attr_list(&list.attrs, line_num, ctx, true, &[]);
1458− ctx.in_bundle = false;
1459− ctx.env.define(name, Binding::Bundle(Rc::new(attrs)));
1460− ctx.define_lines.entry(name.to_string()).or_insert(line_num);
1461− }
1462− // `@let size 16px`, `@let fruits apple, banana`,
1463− // `@let post $posts.0`: see `slot_value`
1464− LetForm::Value(value) => {
1465− let (value, _) =
1466− ctx.slot_value(&value.raw, value.span.line, Some(value.span.column));
1467− set_variable(name, value, line_num, ctx);
1468− }
1469− // Quoted text: `@let arrow "→ "`
1470− LetForm::Quoted(value) => {
1471− let raw = format!("\"{}\"", value.raw);
1472− let column = value.span.column.saturating_sub(1);
1473− let (text, quoted, _) =
1474− ctx.fill_value(&raw, value.span.line, Some(column), Sink::Text);
1475− let value = quoted.map_or(Value::Str(text), Value::Quoted);
1476− set_variable(name, value, line_num, ctx);
1477− }
1478− }
1479− Ok(None)
1480− }
1481−
1482− // @meta NAME VALUE; `og:` names become Open Graph property tags
1483− ("meta", DirectiveArgs::Text(Some(arg))) => {
1484− let Some((name, value)) = arg.raw.split_once(char::is_whitespace) else {
1485− ctx.diagnostics.push(
1486− Diagnostic::error(
1487− code::MISSING_ARGUMENT,
1488− line_num,
1489− format!("@meta needs a name and a value: `@meta {} VALUE`", arg.raw),
1490− )
1491− .source(content.clone()),
1492− );
1493− return Ok(None);
1494− };
1495− let value_column = arg.span.column + arg.raw.len() - value.trim_start().len();
1496− // An HTML attribute value: quoted text loses its quotes
1497− let (value, _, _) =
1498− ctx.fill_value(value.trim(), line_num, Some(value_column), Sink::Text);
1499− // The same tag twice says nothing more (a layout called
1500− // twice): it is written once
1501− let (tags, tag) = match name.trim().strip_prefix("og:") {
1502− Some(property) => (&mut ctx.og_tags, (property.to_string(), value)),
1503− None => (&mut ctx.meta_tags, (name.trim().to_string(), value)),
1504− };
1505− if !tags.contains(&tag) {
1506− tags.push(tag);
1507− }
1508− ctx.head_at.get_or_insert(line_num);
1509− Ok(None)
1510− }
1511−
1512− ("head", _) => {
1513− let text = verbatim_content(node);
1514− if !text.trim().is_empty() {
1515− ctx.head_blocks.push(text.trim().to_string());
1516− ctx.head_at.get_or_insert(line_num);
1517− }
1518− Ok(None)
1519− }
1520−
1521− // @style: raw CSS
1522− ("style", _) => {
1523− let text = verbatim_content(node);
1524− // Only the @style at the top of a function's body is
1525− // scoped; anywhere else `&` is `:scope`, the whole page
1526− if has_top_level_ampersand(&text) {
1527− ctx.push_once(Diagnostic::warning(
1528− code::INVALID_VALUE,
1529− node.span.line,
1530− "`&` in this @style is the whole page: only an @style at the top of a \
1531− function's body is scoped to the function, with `&` its root element"
1532− .to_string(),
1533− ));
1534− }
1535− if !text.trim().is_empty() {
1536− ctx.custom_css.push(text.trim().to_string());
1537− }
1538− Ok(None)
1539− }
1540−
1541− // @markdown: an indented block, or a file
1542− ("markdown", DirectiveArgs::Text(file)) => {
1543− let Some(file) = file else {
1544− let md_lines: Vec<String> = verbatim_text(&node.children)
1545− .lines()
1546− .map(String::from)
1547− .collect();
1548− return Ok(Some(vec![Node::Raw(markdown_to_html(&md_lines))]));
1549− };
1550− let filename = ctx.interpolate_text(&file.raw, line_num, Some(file.span.column));
1551− let resolved = ctx.resolve(&filename);
1552− let md_text = match ctx.read_file(&resolved) {
1553− Ok(text) => text,
1554− Err(e) => {
1555− ctx.diagnostics.push(
1556− Diagnostic::error(
1557− code::UNREADABLE_FILE,
1558− line_num,
1559− format!("cannot read markdown '{}': {}", filename, e),
1560− )
1561− .source(content.clone()),
1562− );
1563− return Ok(None);
1564− }
1565− };
1566− ctx.included_files.push(resolved);
1567− let md_lines: Vec<String> = md_text.lines().map(|l| l.to_string()).collect();
1568− Ok(Some(vec![Node::Raw(markdown_to_html(&md_lines))]))
1569− }
1570−
1571− ("include", DirectiveArgs::Text(Some(path))) => {
1572− self.eval_include(node.id, path, line_num, content, ctx)
1573− }
1574−
1575− ("data", DirectiveArgs::Data { name, source, .. }) => {
1576− self.eval_data(name, source, line_num, content, ctx);
1577− Ok(None)
1578− }
1579−
1580− // @raw: the rest of its line, or its indented body, verbatim
1581− ("raw", _) => {
1582− let text = verbatim_content(node);
1583− let text = text.trim_end_matches('\n');
1584− Ok((!text.is_empty()).then(|| vec![Node::Raw(text.to_string())]))
1585− }
1586−
1587− // A header with a syntax error (reported), or a directive
1588− // without its argument
1589− _ => Ok(None),
1590− }
1591− }
1592−
1593− fn eval_include(
1594− &mut self,
1595− id: usize,
1596− path: &syntax::Arg,
1597− line_num: usize,
1598− content: &str,
1599− ctx: &mut ParseContext,
1600− ) -> Result<Option<Vec<Node>>, ParseError> {
1601− let (filename, column) = match path.raw.strip_prefix('"').and_then(|f| f.strip_suffix('"'))
1602− {
1603− Some(quoted) => (quoted, path.span.column + 1),
1604− None => (path.raw.as_str(), path.span.column),
1605− };
1606− let filename = ctx.interpolate_text(filename, line_num, Some(column));
1607− let resolved = ctx.resolve(&filename);
1608−
1609− if ctx.include_stack.contains(&resolved) {
1610− let cycle_chain = format_include_chain(&ctx.include_stack);
1611− ctx.diagnostics.push(
1612− Diagnostic::error(
1613− code::CIRCULAR_INCLUDE,
1614− line_num,
1615− format!(
1616− "circular include '{}' (cycle: {} → {})",
1617− filename, cycle_chain, filename
1618− ),
1619− )
1620− .source(content),
1621− );
1622− return Ok(None);
1623− }
1624−
1625− let imported_text = match ctx.read_file(&resolved) {
1626− Ok(text) => text,
1627− Err(e) => {
1628− ctx.diagnostics.push(
1629− Diagnostic::error(
1630− code::UNREADABLE_FILE,
1631− line_num,
1632− format!("cannot include '{}': {}", filename, e),
1633− )
1634− .source(content),
1635− );
1636− return Ok(None);
1637− }
1638− };
1639−
1640− ctx.included_files.push(resolved.clone());
1641− ctx.include_stack.push(resolved.clone());
1642− let saved_base = ctx.base_path.clone();
1643− ctx.base_path = resolved.parent().map(|p| p.to_path_buf());
1644−
1645− let diag_count_before = ctx.diagnostics.len();
1646− let import_chain = format_include_chain(&ctx.include_stack);
1647− let tree = ctx.parse_tree(&imported_text);
1648− ctx.diagnostics.extend(tree.diagnostics.iter().cloned());
1649− ctx.trees.push((tree.clone(), Some(import_chain.clone())));
1650− let files = Rc::make_mut(&mut ctx.included_by).entry(id).or_default();
1651− if !files.iter().any(|(_, chain)| *chain == import_chain) {
1652− files.push((tree.clone(), import_chain.clone()));
1653− }
1654− let saved_file = ctx.current_file.replace(import_chain.clone());
1655− let defined_before: HashSet<String> = ctx
1656− .let_lines
1657− .keys()
1658− .chain(ctx.define_lines.keys())
1659− .chain(ctx.fn_lines.keys())
1660− .cloned()
1661− .collect();
1662− let included_nodes = self.eval_block(&tree.nodes, ctx);
1663− ctx.current_file = saved_file;
1664− // An included file's definitions aren't reported unused here, where
1665− // their lines aren't this file's: a library's are there to be
1666− // picked from, and any other file reports its own when checked
1667− let keep = |name: &String, _: &mut usize| defined_before.contains(name);
1668− ctx.let_lines.retain(keep);
1669− ctx.define_lines.retain(keep);
1670− ctx.fn_lines.retain(keep);
1671−
1672− // Annotate new diagnostics with import chain
1673− for d in &mut ctx.diagnostics[diag_count_before..] {
1674− d.message = format!("{}\n in {}", d.message, import_chain);
1675− }
1676−
1677− ctx.base_path = saved_base;
1678− ctx.include_stack.pop();
1679− Ok(Some(included_nodes))
1680− }
1681−
1682− /// @data $name file.json values as $name.key
1683− /// @data $name dir/*.json a list of the files' records
1684− /// @data $name [...] / {...} inline JSON
1685− /// @data $name env:NAME [DEFAULT] an environment variable
1686− fn eval_data(
1687− &mut self,
1688− prefix: &str,
1689− source: &syntax::Arg,
1690− line_num: usize,
1691− content: &str,
1692− ctx: &mut ParseContext,
1693− ) {
1694− let prefix = prefix.to_string();
1695− let filename = source.raw.as_str();
1696− if let Some(env) = filename.strip_prefix("env:") {
1697− let (var, default) = match env.split_once(char::is_whitespace) {
1698− Some((var, default)) => (var, Some(default.trim())),
1699− None => (env, None),
1700− };
1701− let default_column = default.map(|d| source.span.column + filename.len() - d.len());
1702− let value = std::env::var(var)
1703− .ok()
1704− .or_else(|| default.map(|d| ctx.interpolate_text(d, line_num, default_column)));
1705− if value.is_none() {
1706− ctx.diagnostics.push(
1707− Diagnostic::warning(
1708− code::UNSET_ENVIRONMENT,
1709− line_num,
1710− format!(
1711− "environment variable '{}' is not set and has no default",
1712− var
1713− ),
1714− )
1715− .source(content),
1716− );
1717− }
1718− ctx.bind(&prefix, Value::Str(value.unwrap_or_default()));
1719− return;
1720− }
1721−
1722− // Inline JSON: @data $links [{"label": "Home", "url": "/"}]
1723− let (json_text, source) = if filename.starts_with(['[', '{']) {
1724− (filename.to_string(), "the inline data".to_string())
1725− } else {
1726− let filename = ctx.interpolate_text(filename, line_num, Some(source.span.column));
1727− if filename.contains('*') {
1728− self.load_data_glob(&prefix, &filename, line_num, content, ctx);
1729− return;
1730− }
1731− let resolved = ctx.resolve(&filename);
1732− match std::fs::read_to_string(&resolved) {
1733− Ok(text) => {
1734− ctx.included_files.push(resolved);
1735− (text, format!("'{}'", filename))
1736− }
1737− Err(e) => {
1738− ctx.diagnostics.push(
1739− Diagnostic::error(
1740− code::UNREADABLE_FILE,
1741− line_num,
1742− format!("cannot load data '{}': {}", filename, e),
1743− )
1744− .source(content),
1745− );
1746− return;
1747− }
1748− }
1749− };
1750− match parse_json_with_error(&json_text) {
1751− Ok(json) => ctx.bind(&prefix, json_value(json)),
1752− Err(detail) => ctx.diagnostics.push(
1753− Diagnostic::error(
1754− code::INVALID_JSON,
1755− line_num,
1756− format!("invalid JSON in {}: {}", source, detail),
1757− )
1758− .source(content),
1759− ),
1760− }
1761− }
1762−
1763− /// `@data $name dir/*.json`: a list with one record per matching file
1764− /// (in name order), whose `file` is the file's name without extension.
1765− fn load_data_glob(
1766− &mut self,
1767− name: &str,
1768− pattern: &str,
1769− line_num: usize,
1770− content: &str,
1771− ctx: &mut ParseContext,
1772− ) {
1773− let base = ctx.base_path.clone().unwrap_or_else(|| PathBuf::from("."));
1774− let pattern_path = Path::new(pattern);
1775− let dir = match pattern_path.parent() {
1776− Some(dir) if !dir.as_os_str().is_empty() => base.join(dir),
1777− _ => base,
1778− };
1779− let file_pattern = pattern_path
1780− .file_name()
1781− .unwrap_or_default()
1782− .to_string_lossy()
1783− .to_string();
1784− let mut files: Vec<PathBuf> = match std::fs::read_dir(&dir) {
1785− Ok(entries) => entries
1786− .flatten()
1787− .map(|e| e.path())
1788− .filter(|p| {
1789− p.file_name()
1790− .is_some_and(|n| glob_match(&file_pattern, &n.to_string_lossy()))
1791− })
1792− .collect(),
1793− Err(e) => {
1794− ctx.diagnostics.push(
1795− Diagnostic::new(
1796− code::UNREADABLE_FILE,
1797− Severity::Error,
1798− line_num,
1799− format!("cannot read directory for '{}': {}", pattern, e),
1800− )
1801− .source(content.to_string()),
1802− );
1803− return;
1804− }
1805− };
1806− files.sort();
1807− let mut records = Vec::new();
1808− for file in files {
1809− let stem = file
1810− .file_stem()
1811− .unwrap_or_default()
1812− .to_string_lossy()
1813− .to_string();
1814− let text = match std::fs::read_to_string(&file) {
1815− Ok(text) => text,
1816− Err(e) => {
1817− ctx.diagnostics.push(
1818− Diagnostic::new(
1819− code::UNREADABLE_FILE,
1820− Severity::Error,
1821− line_num,
1822− format!("cannot load data '{}': {}", file.display(), e),
1823− )
1824− .source(content.to_string()),
1825− );
1826− continue;
1827− }
1828− };
1829− match parse_json_with_error(&text) {
1830− Ok(JsonValue::Object(mut pairs)) => {
1831− if !pairs.iter().any(|(key, _)| key == "file") {
1832− pairs.push(("file".to_string(), JsonValue::Str(stem)));
1833− }
1834− records.push(JsonValue::Object(pairs));
1835− }
1836− Ok(_) => ctx.diagnostics.push(
1837− Diagnostic::new(
1838− code::INVALID_JSON,
1839− Severity::Error,
1840− line_num,
1841− format!("'{}' should hold a JSON object", file.display()),
1842− )
1843− .source(content.to_string()),
1844− ),
1845− Err(detail) => ctx.diagnostics.push(
1846− Diagnostic::new(
1847− code::INVALID_JSON,
1848− Severity::Error,
1849− line_num,
1850− format!("invalid JSON in '{}': {}", file.display(), detail),
1851− )
1852− .source(content.to_string()),
1853− ),
1854− }
1855− ctx.included_files.push(file);
1856− }
1857− ctx.bind(name, json_value(JsonValue::Array(records)));
1858− }
1859−
1860− /// `@each $item in LIST` or `@each $item, $index in LIST`, with the
1861− /// `@else` that follows it. LIST is a value (see
1862− /// [`ParseContext::slot_value`]): a list written with commas, a range,
1863− /// or one `$name` or `${...}` that holds a list. Each item is bound
1864− /// whole to `$item`, and each iteration is a block of its own.
1865− fn eval_each(
1866− &mut self,
1867− node: &syntax::Node,
1868− empty_branch: Option<&syntax::Node>,
1869− ctx: &mut ParseContext,
1870− ) -> Result<Option<Vec<Node>>, ParseError> {
1871− ctx.visited.insert(node.id);
1872− if let Some(branch) = empty_branch {
1873− ctx.visited.insert(branch.id);
1874− }
1875− ctx.enter(node);
1876− // A malformed header is a syntax error, already reported
1877− let Some(DirectiveArgs::Each(header)) = node.directive().map(|d| &d.args) else {
1878− return Ok(None);
1879− };
1880− let body = &node.children;
1881− let empty: &[syntax::Node] = empty_branch.map_or(&[], |b| &b.children);
1882− let (item, index) = (header.item.as_str(), header.index.as_deref());
1883− let list = &header.list;
1884− // `[...]` is an attribute list or JSON elsewhere, not a list here
1885− let bracketed = list.raw.starts_with('[') && list.raw.ends_with(']');
1886− let (source, filled) = match bracketed {
1887− true => (Value::empty(), false),
1888− false => ctx.slot_value(&list.raw, list.span.line, Some(list.span.column)),
1889− };
1890− let not_a_list = |message: String, ctx: &ParseContext| {
1891− let diagnostic = Diagnostic::error(code::INVALID_LOOP, list.span.line, message)
1892− .column(list.span.column)
1893− .subject(list.raw.as_str());
1894− match &ctx.current_source {
1895− (current, Some(text)) if *current == list.span.line => {
1896− diagnostic.source(text.clone())
1897− }
1898− _ => diagnostic,
1899− }
1900− };
1901− if bracketed {
1902− let inner = list.raw[1..list.raw.len() - 1].trim().to_string();
1903− let diagnostic = not_a_list(
1904− format!(
1905− "@each takes a list written without brackets, `@each ${} in {}`; \
1906− JSON data goes in `@data`",
1907− item, inner
1908− ),
1909− ctx,
1910− )
1911− .suggest(Some(inner));
1912− ctx.push_once(diagnostic);
1913− }
1914− let items: Vec<Value> = match source {
1915− Value::List(list) => list.items.to_vec(),
1916− // Reported (an undefined `$name`, brackets): there is nothing
1917− // to repeat
1918− _ if !filled => Vec::new(),
1919− Value::Record(_) => {
1920− let diagnostic = not_a_list(
1921− format!(
1922− "@each repeats for the items of a list, and `{}` is a record: \
1923− loop over a list of records, or use its fields",
1924− list.raw
1925− ),
1926− ctx,
1927− );
1928− ctx.push_once(diagnostic);
1929− Vec::new()
1930− }
1931− // Empty text (a field a record doesn't have) is no items; any
1932− // other value is one
1933− value if value.to_string().is_empty() => Vec::new(),
1934− value => vec![value],
1935− };
1936−
1937− if body.iter().all(syntax::Node::is_trivia) {
1938− return Ok(Some(Vec::new()));
1939− }
1940− if items.is_empty() {
1941− return Ok(Some(self.eval_scoped(empty, ctx)));
1942− }
1943− let mut nodes = Vec::new();
1944− for (i, value) in items.into_iter().enumerate() {
1945− ctx.env.push();
1946− ctx.bind(item, value);
1947− if let Some(index) = index {
1948− ctx.bind(index, Value::Num(i as f64));
1949− }
1950− nodes.extend(self.eval_block(body, ctx));
1951− ctx.env.pop();
1952− }
1953− Ok(Some(nodes))
1954− }
1955−
1956− fn define_function(
1957− &mut self,
1958− name: &str,
1959− params: &[syntax::Param],
1960− node: &syntax::Node,
1961− ctx: &mut ParseContext,
1962− ) {
1963− let line_num = node.span.line;
1964− let body = &node.children;
1965− // An @style block at the top of the body is scoped to the
1966− // function: its rules apply inside a `.hl-fn-NAME-HASH` wrapper (a
1967− // generated class never has a second `-`, so the two can't meet).
1968− // The hash is the stylesheet's, so two functions of one name with
1969− // two stylesheets, in two files, don't style each other's elements
1970− // in a page that has both. It is written into the page when the
1971− // function is called.
1972− let (style, body): (Vec<&syntax::Node>, Vec<&syntax::Node>) =
1973− body.iter().partition(|node| node.is_directive("style"));
1974− let scoped = (!style.is_empty()).then(|| {
1975− let css: String = style
1976− .iter()
1977− .map(|node| {
1978− ctx.visited.insert(node.id);
1979− verbatim_content(node)
1980− })
1981− .collect();
1982− let digits = crate::codegen::CLASS_DIGITS;
1983− let hash = crate::codegen::hash_digits(crate::codegen::stable_hash(&css), digits);
1984− let class = format!("hl-fn-{}-{}", name, hash);
1985− // Nested under the scope class, so any CSS works (multi-line
1986− // rules, at-rules)
1987− let css = if css.trim().is_empty() {
1988− String::new()
1989− } else {
1990− format!(".{} {{\n{}}}", class, css)
1991− };
1992− (class, css)
1993− });
1994−
1995− // A default is filled in only when a call leaves its parameter
1996− // out, so the names in it count as used here
1997− for default in params.iter().filter_map(|p| p.default.as_ref()) {
1998− track_var_refs(default, &mut ctx.used_variables);
1999− }
2000− ctx.fn_lines.entry(name.to_string()).or_insert(line_num);
2001− let wraps_itself = ElementKind::from_name(name).is_some()
2002− && body.iter().any(|node| calls_unguarded(node, name));
2003− if wraps_itself {
2004− ctx.push_once(
2005− Diagnostic::error(
2006− code::RECURSIVE_CALL,
2007− line_num,
2008− format!(
2009− "@{0} in the body of `@let @{0}` calls the function itself, not the \
2010− element @{0}, so it would never stop: give the function another name \
2011− (such as @site-{0})",
2012− name
2013− ),
2014− )
2015− .subject(name),
2016− );
2017− }
2018− for node in &body {
2019− node.walk(&mut |node| {
2020− if let Some(d) = marker_in_text(node) {
2021− ctx.push_once(d);
2022− }
2023− });
2024− }
2025− let body: Vec<syntax::Node> = body.into_iter().cloned().collect();
2026− let (slots, has_children) = declared_slots(&body, ctx);
2027− let function = Rc::new(FnDef {
2028− params: params.to_vec(),
2029− line: line_num,
2030− source: ctx.current_source.1.clone(),
2031− node: node.id,
2032− body,
2033− file: ctx.current_file.clone(),
2034− slots,
2035− has_children,
2036− scoped,
2037− env: ctx.env.clone(),
2038− wraps_itself,
2039− });
2040− ctx.defined_functions
2041− .insert(name.to_string(), function.clone());
2042− ctx.env.define(name, Binding::Function(function));
2043− }
2044−
2045− /// An element line: a chain of elements and function calls, the last of
2046− /// which gets the indented children.
2047− fn eval_element(
2048− &mut self,
2049− node: &syntax::Node,
2050− element: &syntax::ElementLine,
2051− ctx: &mut ParseContext,
2052− ) -> Result<Vec<Node>, ParseError> {
2053− // An unclosed attribute list is a syntax error, already reported
2054− if element
2055− .chain
2056− .iter()
2057− .any(|h| h.attrs.as_ref().is_some_and(|a| !a.closed))
2058− {
2059− return Ok(Vec::new());
2060− }
2061− let line_num = node.span.line;
2062− let last = element.chain.len() - 1;
2063− // Each head is read where it is written, left to right. The
2064− // children belong to the last one, so the chain is built right to
2065− // left, each link wrapping the next.
2066− let mut links = Vec::new();
2067− for (i, head) in element.chain.iter().enumerate() {
2068− let text = if i == last {
2069− element.text.as_ref()
2070− } else {
2071− None
2072− };
2073− links.push(resolve(head, text, line_num, &node.source, ctx)?);
2074− }
2075− let calls: Vec<Option<(String, Rc<FnDef>)>> = links
2076− .iter()
2077− .map(|link| match link {
2078− Resolved::Call(call) => Some((call.name.clone(), call.function.clone())),
2079− Resolved::Element(_) => None,
2080− })
2081− .collect();
2082− let mut current = self.eval_scoped(&node.children, ctx);
2083− // After the lines under the call ran, so the files they include
2084− // are read
2085− check_fillers(node, element, &calls, ctx);
2086− for link in links.into_iter().rev() {
2087− current = self.complete(link, current, ctx)?;
2088− }
2089− Ok(current)
2090− }
2091−
2092− /// Give a resolved `@name` its children: an element holds them, and a
2093− /// function's body puts them where its `@children` is.
2094− fn complete(
2095− &mut self,
2096− resolved: Resolved,
2097− children: Vec<Node>,
2098− ctx: &mut ParseContext,
2099− ) -> Result<Vec<Node>, ParseError> {
2100− match resolved {
2101− Resolved::Element(mut element) => {
2102− element.children.extend(children);
2103− let line = element.line_num;
2104− Ok(vec![inline_svg(Node::Element(element), line, ctx)])
2105− }
2106− Resolved::Call(call) => self.expand_fn_call(*call, children, ctx),
2107− }
2108− }
2109−
2110− fn expand_fn_call(
2111− &mut self,
2112− call: Call,
2113− all_caller_children: Vec<Node>,
2114− ctx: &mut ParseContext,
2115− ) -> Result<Vec<Node>, ParseError> {
2116− let Call {
2117− name,
2118− function: fn_def,
2119− args,
2120− values,
2121− text: trailing_text,
2122− written_form,
2123− written_keys,
2124− line: line_num,
2125− name_at,
2126− source: content,
2127− } = call;
2128− let (name, content) = (name.as_str(), content.as_str());
2129−
2130− // Separate the caller's `@slot NAME` blocks from its other
2131− // children. A block for a slot the function doesn't declare was
2132− // reported where it is written (see `check_fillers`), like one
2133− // without a name.
2134− let mut slot_contents: HashMap<String, Vec<Node>> = HashMap::new();
2135− let mut caller_children = Vec::new();
2136− for child in all_caller_children {
2137− if let Node::Element(elem) = child {
2138− match elem.kind {
2139− ElementKind::Slot(slot_name) => {
2140− slot_contents
2141− .entry(slot_name)
2142− .or_default()
2143− .extend(elem.children);
2144− }
2145− kind => caller_children.push(Node::Element(Element { kind, ..elem })),
2146− }
2147− continue;
2148− }
2149− caller_children.push(child);
2150− }
2151− // Text after the call, as in `@card [color red] New`, is content:
2152− // it goes first among the caller's children, and like them it is
2153− // evaluated where the call is written.
2154− if let Some(text) = &trailing_text {
2155− caller_children.insert(0, Node::Text(text_segments(text, ctx)));
2156− }
2157− // Content goes where the body's `@children` is: without one, it
2158− // would be dropped
2159− if !fn_def.has_children && !caller_children.is_empty() {
2160− let (column, text) = match &name_at {
2161− Some((column, text)) => (Some(*column), text.as_str()),
2162− None => (None, content),
2163− };
2164− ctx.push_once(no_children(name, line_num, column).source(text));
2165− }
2166−
2167− if fn_def.wraps_itself {
2168− return Ok(Vec::new());
2169− }
2170− // Only the body is inside the call, so a function may appear in the
2171− // content its caller passes it. A function may call itself, under
2172− // a condition that stops it; one that doesn't stop goes too deep.
2173− if ctx.too_deep {
2174− return Ok(Vec::new());
2175− }
2176− if ctx.fn_call_stack.len() >= MAX_CALL_DEPTH {
2177− ctx.too_deep = true;
2178− return Err(too_deep(name, &ctx.fn_call_stack, line_num).source(content));
2179− }
2180− let caller = (
2181− ctx.current_line,
2182− ctx.current_source.clone(),
2183− ctx.current_node,
2184− );
2185− ctx.fn_call_stack.push(name.to_string());
2186−
2187− // The body runs where the function is defined: it sees what was
2188− // visible there, the function itself (so it can call itself), and
2189− // its parameters, bound by name in the order they are declared. A
2190− // default is filled in at the call, seeing the same, with the
2191− // parameters before it.
2192− let caller_env = std::mem::replace(&mut ctx.env, fn_def.env.clone());
2193− ctx.env.push();
2194− ctx.env.define(name, Binding::Function(fn_def.clone()));
2195− let mut consumed = vec![false; args.len()];
2196− for param in &fn_def.params {
2197− let mut passed = None;
2198− for (j, arg) in args.iter().enumerate() {
2199− if arg.key != param.name {
2200− continue;
2201− }
2202− consumed[j] = true;
2203− // The later one wins, as for any attribute: one written
2204− // after a bundle overrides it, and only one written twice
2205− // in the call's own list is reported
2206− if passed.is_some() && written_keys.iter().filter(|k| **k == param.name).count() > 1
2207− {
2208− ctx.push_once(
2209− Diagnostic::warning(
2210− code::DUPLICATE_ATTRIBUTE,
2211− line_num,
2212− format!(
2213− "parameter '{}' of @{} is passed twice: the later one wins",
2214− param.name, name
2215− ),
2216− )
2217− .source(content)
2218− .subject(param.name.as_str()),
2219− );
2220− }
2221− // Written `name=value` in the call's own list is reported
2222− // as written; this is one from a bundle
2223− if arg.html && !written_form.contains(&arg.key) {
2224− let value = arg.value.as_deref().unwrap_or("");
2225− ctx.push_once(parameter_form(name, &arg.key, value, line_num).source(content));
2226− }
2227− passed = Some(j);
2228− }
2229− let value = match passed {
2230− // A parameter's name alone is true: `@post-card [featured]`
2231− Some(j) if args[j].value.is_none() => Value::Bool(true),
2232− // What the call passed, with its type: a record, a list,
2233− // quoted text
2234− Some(j) => values[j].clone().unwrap_or_else(|| {
2235− let arg = &args[j];
2236− match &arg.quoted {
2237− Some(quoted) => Value::Quoted(quoted.clone()),
2238− None => Value::Str(arg.value.clone().unwrap_or_default()),
2239− }
2240− }),
2241− None => match ¶m.default {
2242− Some(default) => {
2243− let before = ctx.diagnostics.len();
2244− let value = fill_default(&fn_def, param, default, ctx);
2245− point_at_call(ctx, before, &fn_def, name, line_num, content);
2246− value
2247− }
2248− None => {
2249− let (column, text) = match &name_at {
2250− Some((column, text)) => (Some(*column), text.as_str()),
2251− None => (None, content),
2252− };
2253− ctx.push_once(
2254− missing_parameter(name, ¶m.name, line_num, column).source(text),
2255− );
2256− Value::empty()
2257− }
2258− },
2259− };
2260− ctx.bind(¶m.name, value);
2261− }
2262− // Arguments that aren't parameters are attributes for the
2263− // function's root element, so a function can be styled like an
2264− // element: `@card [background red] New`.
2265− let forwarded: Vec<Attribute> = args
2266− .iter()
2267− .zip(&consumed)
2268− .filter(|&(_, &used)| !used)
2269− .map(|(a, _)| a.clone())
2270− .collect();
2271−
2272− // Evaluate the body with the parameters in scope, as lines of the
2273− // file that defines the function
2274− let caller_file = std::mem::replace(&mut ctx.current_file, fn_def.file.clone());
2275− let before = ctx.diagnostics.len();
2276− let mut body_nodes = self.eval_block(&fn_def.body, ctx);
2277− ctx.current_file = caller_file;
2278− point_at_call(ctx, before, &fn_def, name, line_num, content);
2279−
2280− // Back to the caller's names and call stack
2281− ctx.env = caller_env;
2282− ctx.fn_call_stack.pop();
2283− if ctx.fn_call_stack.is_empty() {
2284− ctx.too_deep = false;
2285− }
2286− (ctx.current_line, ctx.current_source, ctx.current_node) = caller;
2287−
2288− // What the body wrote is the call's
2289− belongs_to_call(&mut body_nodes, name, line_num);
2290−
2291− // Replace @children with caller's children and @slot with slot content
2292− let mut result_nodes =
2293− replace_children_and_slots(body_nodes, &caller_children, &slot_contents);
2294−
2295− // Attributes that aren't parameters style the function's root
2296− // element, and a scoped @style's class goes on it too.
2297− let scope_class = fn_def.scoped.as_ref().map(|(class, _)| class.clone());
2298− if !forwarded.is_empty() || scope_class.is_some() {
2299− let mut roots = result_nodes.iter_mut().filter_map(|n| match n {
2300− Node::Element(e) => Some(e),
2301− _ => None,
2302− });
2303− let root = match (roots.next(), roots.next()) {
2304− (Some(root), None) => Some(root),
2305− _ => None,
2306− };
2307− let mut problems = Vec::new();
2308− match root {
2309− Some(root) => {
2310− // A call's `class=` adds to the root's own classes
2311− for attr in forwarded {
2312− let existing = (attr.html && attr.key == "class")
2313− .then(|| root.attrs.iter_mut().find(|a| a.html && a.key == "class"))
2314− .flatten();
2315− match existing {
2316− Some(class) => {
2317− let mut value = class.value.take().unwrap_or_default();
2318− for name in attr.value.as_deref().unwrap_or("").split_whitespace() {
2319− if !value.split_whitespace().any(|c| c == name) {
2320− value.push(' ');
2321− value.push_str(name);
2322− }
2323− }
2324− class.value = Some(value.trim().to_string());
2325− }
2326− None => root.attrs.push(attr),
2327− }
2328− }
2329− // The scoped `@style` goes into the page once, when the
2330− // function is first called
2331− if let Some((_, css)) = &fn_def.scoped
2332− && !css.is_empty()
2333− && !ctx.scoped_css.contains(css)
2334− {
2335− ctx.scoped_css.push(css.clone());
2336− }
2337− if let Some(class) = scope_class {
2338− match root.attrs.iter_mut().find(|a| a.html && a.key == "class") {
2339− Some(attr) => {
2340− let existing = attr.value.take().unwrap_or_default();
2341− attr.value =
2342− Some(format!("{} {}", existing, class).trim().to_string());
2343− }
2344− None => root.attrs.push(Attribute {
2345− key: "class".to_string(),
2346− value: Some(class),
2347− html: true,
2348− quoted: None,
2349− }),
2350− }
2351− }
2352− }
2353− None => {
2354− if !forwarded.is_empty() {
2355− problems.push(format!(
2356− "attributes {} on @{} are not parameters, and its body has no single \
2357− root element to receive them",
2358− forwarded
2359− .iter()
2360− .map(|a| format!("'{}'", a.key))
2361− .collect::<Vec<_>>()
2362− .join(", "),
2363− name
2364− ));
2365− }
2366− if scope_class.is_some() {
2367− problems.push(format!(
2368− "@{} has a scoped @style, but its body has no single root element \
2369− to scope it to",
2370− name
2371− ));
2372− }
2373− }
2374− }
2375− for message in problems {
2376− ctx.diagnostics.push(
2377− Diagnostic::error(code::NO_SINGLE_ROOT, line_num, message)
2378− .source(content)
2379− .subject(name),
2380− );
2381− }
2382− }
2383−
2384− Ok(result_nodes)
2385− }
2386−}
2387−
2388−/// A `@name` read where it is written: a built-in element, or a call.
2389−enum Resolved {
2390− Element(Element),
2391− Call(Box<Call>),
2392−}
2393−
2394−/// A call of a function, with its arguments evaluated where it is written.
2395−struct Call {
2396− name: String,
2397− function: Rc<FnDef>,
2398− args: Vec<Attribute>,
2399− /// The value of each argument that passes a parameter, with its type
2400− /// (see [`ParseContext::slot_value`]), in the order of `args`.
2401− values: Vec<Option<Value>>,
2402− /// Text after the attributes, which is content.
2403− text: Option<syntax::Text>,
2404− /// Parameters written `name=value`, already reported.
2405− written_form: Vec<String>,
2406− /// The keys written in the call's own list, not from a bundle.
2407− written_keys: Vec<String>,
2408− line: usize,
2409− /// The column of the call's name and the line it is on, for a missing
2410− /// parameter.
2411− name_at: Option<(usize, String)>,
2412− /// The line as written, for diagnostics.
2413− source: String,
2414−}
2415−
2416−/// What `@name` is where it is written: a call of the function `name`
2417−/// when one is defined, else the built-in element. A whole line, each link
2418−/// of a chain and an inline element in text all resolve here.
2419−fn resolve(
2420− head: &syntax::Head,
2421− text: Option<&syntax::Text>,
2422− line: usize,
2423− source: &str,
2424− ctx: &mut ParseContext,
2425−) -> Result<Resolved, ParseError> {
2426− let Some(function) = ctx.env.function(&head.name).cloned() else {
2427− return parse_single_element(head, text, line, ctx).map(Resolved::Element);
2428− };
2429− ctx.used_functions.insert(head.name.clone());
2430− let params: Vec<String> = function.params.iter().map(|p| p.name.clone()).collect();
2431− let written = head.attrs.as_ref().map_or(&[][..], |list| &list.attrs[..]);
2432− let written_form = written_parameter_forms(&head.name, &function, written, line, ctx);
2433− let written_keys = written.iter().map(|a| a.key.clone()).collect();
2434− // Parameters are bound by name; every other attribute goes to the
2435− // root element, and is checked like any attribute
2436− let (args, values) = parse_attrs(written, line, ctx, true, ¶ms)
2437− .into_iter()
2438− .unzip();
2439− let name_at = name_column(head, line).zip(match &ctx.current_source {
2440− (current, Some(text)) if *current == line => Some(text.clone()),
2441− _ => None,
2442− });
2443− Ok(Resolved::Call(Box::new(Call {
2444− name: head.name.clone(),
2445− function,
2446− args,
2447− values,
2448− text: text.cloned(),
2449− written_form,
2450− written_keys,
2451− line,
2452− name_at,
2453− source: source.to_string(),
2454− })))
2455−}
2456−
2457−/// A line of another file (the standard library, an included file) means
2458−/// nothing in this one: the problems reported since `before` while
2459−/// evaluating the function (its body, a default) are moved to the call.
2460−fn point_at_call(
2461− ctx: &mut ParseContext,
2462− before: usize,
2463− function: &FnDef,
2464− name: &str,
2465− line: usize,
2466− source: &str,
2467−) {
2468− if function.file == ctx.current_file {
2469− return;
2470− }
2471− let defined_in = function
2472− .file
2473− .as_deref()
2474− .unwrap_or("the file being compiled");
2475− for d in &mut ctx.diagnostics[before..] {
2476− d.message = format!(
2477− "{}\n in @{} (line {} of {})",
2478− d.message, name, d.line, defined_in
2479− );
2480− d.line = line;
2481− d.column = None;
2482− d.subject = None;
2483− d.suggestion = None;
2484− d.source_line = Some(source.into());
2485− }
2486−}
2487−
2488−/// A call nested deeper than [`MAX_CALL_DEPTH`].
2489−fn too_deep(name: &str, stack: &[String], line: usize) -> Diagnostic {
2490− let message = if stack.iter().any(|n| n == name) {
2491− format!(
2492− "recursive function call to @{} goes more than {} calls deep: a function that \
2493− calls itself needs a condition that stops it (`@if`)",
2494− name, MAX_CALL_DEPTH
2495− )
2496− } else {
2497− format!(
2498− "function calls nest more than {} deep at @{} (starting with {})",
2499− MAX_CALL_DEPTH,
2500− name,
2501− stack
2502− .iter()
2503− .take(3)
2504− .map(|n| format!("@{}", n))
2505− .collect::<Vec<_>>()
2506− .join(" → ")
2507− )
2508− };
2509− Diagnostic::error(code::RECURSIVE_CALL, line, message).subject(name)
2510−}
2511−
2512−/// Mark what a function's body wrote as the call's: it gets the call's
2513−/// line, so what is reported about it points at the call, and the name of
2514−/// the function, unless a call inside the body already claimed it.
2515−fn belongs_to_call(nodes: &mut [Node], function: &str, line: usize) {
2516− fn claim(element: &mut Element, function: &str, line: usize) {
2517− element.line_num = line;
2518− element.function.get_or_insert_with(|| function.to_string());
2519− belongs_to_call(&mut element.children, function, line);
2520− }
2521− for node in nodes {
2522− match node {
2523− Node::Element(element) => claim(element, function, line),
2524− Node::Text(segments) => {
2525− for segment in segments {
2526− if let TextSegment::Inline(element) = segment {
2527− claim(element, function, line);
2528− }
2529− }
2530− }
2531− Node::Raw(_) => {}
2532− }
2533− }
2534−}
2535−
2536−/// What an inline `{@name ...}` stands for in its line of text: an
2537−/// element; the text of a function whose body is text; or, for a body with
2538−/// several roots, its nodes as a fragment.
2539−fn inline_segments(mut nodes: Vec<Node>, line: usize) -> Vec<TextSegment> {
2540− if let [Node::Element(_)] = nodes.as_slice()
2541− && let Some(Node::Element(element)) = nodes.pop()
2542− {
2543− return vec![TextSegment::Inline(element)];
2544− }
2545− if nodes.iter().all(|n| matches!(n, Node::Text(_))) {
2546− let mut segments = Vec::new();
2547− for node in nodes {
2548− if let Node::Text(run) = node {
2549− if !segments.is_empty() {
2550− segments.push(TextSegment::Plain(" ".to_string()));
2551− }
2552− segments.extend(run);
2553− }
2554− }
2555− return segments;
2556− }
2557− vec![TextSegment::Inline(Element {
2558− kind: ElementKind::Fragment,
2559− attrs: Vec::new(),
2560− argument: None,
2561− children: nodes,
2562− line_num: line,
2563− function: None,
2564− })]
2565−}
2566−
2567−/// Fill in the default of a parameter that a call leaves out, like the
2568−/// value of an attribute passed for it: variables are filled in, one
2569−/// `$name` keeps its type and one `"..."` is quoted text. It sees what the
2570−/// body sees: the names visible where the function is defined, and the
2571−/// parameters before it. Its problems are reported at the definition, once.
2572−fn fill_default(
2573− fn_def: &FnDef,
2574− param: &syntax::Param,
2575− default: &str,
2576− ctx: &mut ParseContext,
2577−) -> Value {
2578− // A default that uses a later parameter is an error in the
2579− // definition; the later one isn't bound yet, so don't report it again
2580− let later = fn_def
2581− .params
2582− .iter()
2583− .skip_while(|p| p.name != param.name)
2584− .skip(1);
2585− let names = interp::names(default);
2586− if later.clone().any(|p| names.contains(&p.name.as_str())) {
2587− return Value::empty();
2588− }
2589− let line = param.span.line;
2590− let at_head = line == fn_def.line && fn_def.source.is_some();
2591− let column =
2592− at_head.then(|| param.span.column + (param.span.end - param.span.start) - default.len());
2593− let caller = (
2594− std::mem::replace(
2595− &mut ctx.current_source,
2596− (fn_def.line, fn_def.source.clone()),
2597− ),
2598− std::mem::replace(&mut ctx.current_node, fn_def.node),
2599− );
2600− let (value, _) = ctx.slot_value(default, line, column);
2601− (ctx.current_source, ctx.current_node) = caller;
2602− value
2603−}
2604−
2605−/// Read `@page`'s attribute list and title. The page is the root element,
2606−/// and its attributes are checked like any element's: `key=value` (and a
2607−/// bare boolean HTML attribute) go on `<html>`, styles on `<body>`, and
2608−/// `favicon FILE` is its one word of htmlang's own.
2609−fn read_page(
2610− attrs: Option<&syntax::AttrList>,
2611− title: Option<&syntax::Arg>,
2612− line: usize,
2613− ctx: &mut ParseContext,
2614−) -> Page {
2615− let mut page = Page::default();
2616− if let Some(list) = attrs {
2617− let words: Vec<String> = crate::vocab::PAGE_WORDS
2618− .iter()
2619− .map(|w| w.to_string())
2620− .collect();
2621− ctx.in_page = true;
2622− let read = parse_attr_list(&list.attrs, line, ctx, true, &words);
2623− ctx.in_page = false;
2624− // How many of each name have been read, to find where the next
2625− // one is written
2626− let mut seen: HashMap<String, usize> = HashMap::new();
2627− for attr in read {
2628− let boolean = attr.value.is_none() && crate::vocab::is_html_flag(&attr.key);
2629− // Where it is written, when it is written in the list itself
2630− let nth = seen.entry(attr.key.clone()).or_default();
2631− let column = list
2632− .attrs
2633− .iter()
2634− .filter(|token| token.key == attr.key)
2635− .nth(*nth)
2636− .map(|token| token.span.column);
2637− *nth += 1;
2638− let value = attr
2639− .quoted
2640− .as_ref()
2641− .map(|q| q.text.clone())
2642− .or(attr.value.clone());
2643− if !check_page_attr(&attr.key, attr.html, value.as_deref(), line, column, ctx) {
2644− continue;
2645− }
2646− if words.contains(&attr.key) {
2647− if page.favicon.is_some() {
2648− let diagnostic = Diagnostic::warning(
2649− code::DUPLICATE_ATTRIBUTE,
2650− line,
2651− "duplicate attribute 'favicon': the later one wins".to_string(),
2652− )
2653− .subject("favicon");
2654− ctx.diagnostics.push(at_attribute(diagnostic, column, ctx));
2655− }
2656− // The file itself goes into the page when it can be read
2657− // (relative to the file); otherwise it is linked
2658− page.favicon = value.map(|path| match std::fs::read(ctx.resolve(&path)) {
2659− Ok(data) => crate::codegen::data_uri(&path, &data),
2660− Err(_) => path,
2661− });
2662− } else if attr.html || boolean {
2663− page.html_attrs.push(attr);
2664− } else {
2665− page.styles.push(attr);
2666− }
2667− }
2668− }
2669− page.title = match title {
2670− Some(title) => ctx.interpolate_text(&title.raw, title.span.line, Some(title.span.column)),
2671− None => String::new(),
2672− };
2673− page
2674−}
2675−
2676−/// `@page`'s own rules for one of its attributes, checked where the
2677−/// `@page` runs and where it doesn't (a layout that isn't called): its
2678−/// word is written `favicon FILE`, and `inline` belongs to `@image`.
2679−/// Returns whether the attribute can be used (a `favicon` with its file,
2680−/// or any other attribute but `inline`).
2681−fn check_page_attr(
2682− key: &str,
2683− html: bool,
2684− value: Option<&str>,
2685− line: usize,
2686− column: Option<usize>,
2687− ctx: &mut ParseContext,
2688−) -> bool {
2689− let report = |ctx: &mut ParseContext, diagnostic: Diagnostic| {
2690− let diagnostic = at_attribute(diagnostic, column, ctx);
2691− ctx.diagnostics.push(diagnostic);
2692− };
2693− if crate::vocab::PAGE_WORDS.contains(&key) {
2694− if html {
2695− report(
2696− ctx,
2697− Diagnostic::error(
2698− code::PARAMETER_FORM,
2699− line,
2700− format!(
2701− "'{0}' is @page's own word, not an HTML attribute: write `{0} {1}`",
2702− key,
2703− value.filter(|v| !v.is_empty()).unwrap_or("FILE")
2704− ),
2705− )
2706− .subject(format!("{}=", key))
2707− .suggest(Some(format!("{} ", key))),
2708− );
2709− }
2710− if value.is_none_or(|v| v.trim().is_empty()) {
2711− report(
2712− ctx,
2713− Diagnostic::error(
2714− code::MISSING_VALUE,
2715− line,
2716− format!("'{0}' needs its file: `{0} favicon.png`", key),
2717− )
2718− .subject(key),
2719− );
2720− return false;
2721− }
2722− return true;
2723− }
2724− if !html && crate::vocab::base_attribute(key) == "inline" {
2725− report(
2726− ctx,
2727− Diagnostic::error(
2728− code::UNEXPECTED_ARGUMENT,
2729− line,
2730− "`inline` puts an image's file into the page, and @page has none: it only \
2731− goes on @image"
2732− .to_string(),
2733− )
2734− .subject("inline"),
2735− );
2736− return false;
2737− }
2738− true
2739−}
2740−
2741−/// A parameter passed `name=value`, the form of an HTML attribute.
2742−fn parameter_form(function: &str, key: &str, value: &str, line: usize) -> Diagnostic {
2743− Diagnostic::error(
2744− code::PARAMETER_FORM,
2745− line,
2746− format!(
2747− "'{}' is a parameter of @{}: parameters are written `name value`, so write `{} {}`",
2748− key, function, key, value
2749− ),
2750− )
2751− .subject(format!("{}=", key))
2752− .suggest(Some(format!("{} ", key)))
2753−}
2754−
2755−/// A call that leaves out a parameter without a default.
2756−fn missing_parameter(
2757− function: &str,
2758− param: &str,
2759− line: usize,
2760− column: Option<usize>,
2761−) -> Diagnostic {
2762− let diagnostic = Diagnostic::error(
2763− code::MISSING_PARAMETER,
2764− line,
2765− format!(
2766− "@{} needs '{}': the parameter has no default, so pass it as `{} VALUE`",
2767− function, param, param
2768− ),
2769− )
2770− .subject(param);
2771− match column {
2772− Some(column) => diagnostic.column(column),
2773− None => diagnostic,
2774− }
2775−}
2776−
2777−/// The column of a call's `@name`, when it is on the call's line.
2778−fn name_column(head: &syntax::Head, line: usize) -> Option<usize> {
2779− (head.name_span.line == line).then_some(head.name_span.column)
2780−}
2781−
2782−/// Define `$name`, or, for `--name`, the CSS custom property on `:root`
2783−/// (which gets quoted text with its quotes, and is read with
2784−/// `var(--name)`, never as a variable). `@let name.field value` gives the
2785−/// record `$name` that field (or the list `$name` a new item at that
2786−/// index), as a new value in this block.
2787−fn set_variable(name: &str, value: Value, line_num: usize, ctx: &mut ParseContext) {
2788− if name.starts_with("--") {
2789− let css = value
2790− .quoted_css()
2791− .map_or_else(|| value.to_string(), str::to_string);
2792− let at_line = |diagnostic: Diagnostic, ctx: &ParseContext| match &ctx.current_source {
2793− (current, Some(text)) if *current == line_num => diagnostic.source(text.clone()),
2794− _ => diagnostic,
2795− };
2796− // `:root` is one place for the whole page: a declaration inside a
2797− // block (an element, a loop, a function's body) would not be
2798− // kept to it, and each run would replace the last
2799− if ctx.env.frames.len() > FILE_FRAMES {
2800− let diagnostic = Diagnostic::error(
2801− code::INVALID_DEFINITION,
2802− line_num,
2803− format!(
2804− "`@let {name}` declares {name} on :root, for the whole page, so it goes at \
2805− the top level of the file: to set it on an element and what is inside \
2806− it, write `[{name} value]` on that element"
2807− ),
2808− )
2809− .subject(name);
2810− ctx.push_once(at_line(diagnostic, ctx));
2811− return;
2812− }
2813− match css_breakout(&css) {
2814− Some(reason) => {
2815− let diagnostic = Diagnostic::error(
2816− code::INVALID_VALUE,
2817− line_num,
2818− format!(
2819− "the value of '{}' has {}: `{}` can't be written into the page's CSS",
2820− name, reason, css
2821− ),
2822− )
2823− .subject(css.as_str());
2824− ctx.push_once(at_line(diagnostic, ctx));
2825− }
2826− None => match ctx.css_vars.iter_mut().find(|(n, _)| n == name) {
2827− Some(declared) => {
2828− let diagnostic = Diagnostic::warning(
2829− code::DUPLICATE_ATTRIBUTE,
2830− line_num,
2831− format!(
2832− "{name} is declared again: :root has one value for the whole page, \
2833− so every element gets this one, also above this line (a theme \
2834− redefines a token on an element: `[dark:{name} {css}]`)"
2835− ),
2836− )
2837− .subject(name);
2838− declared.1 = css;
2839− ctx.push_once(at_line(diagnostic, ctx));
2840− }
2841− None => ctx.css_vars.push((name.to_string(), css)),
2842− },
2843− }
2844− return;
2845− }
2846− let mut path = name.split('.');
2847− let root = path.next().unwrap_or(name);
2848− let fields: Vec<&str> = path.collect();
2849− let value = match fields.is_empty() {
2850− true => value,
2851− false => match with_field(ctx.env.value(root).cloned(), root, &fields, value) {
2852− Ok(value) => value,
2853− Err(message) => {
2854− let diagnostic =
2855− Diagnostic::error(code::INVALID_DEFINITION, line_num, message).subject(name);
2856− let diagnostic = match &ctx.current_source {
2857− (current, Some(text)) if *current == line_num => {
2858− diagnostic.source(text.clone())
2859− }
2860− _ => diagnostic,
2861− };
2862− ctx.push_once(diagnostic);
2863− // Reported: the name keeps what it held
2864− ctx.let_lines.entry(root.to_string()).or_insert(line_num);
2865− return;
2866− }
2867− },
2868− };
2869− ctx.bind(root, value);
2870− ctx.let_lines.entry(root.to_string()).or_insert(line_num);
2871−}
2872−
2873−/// `value` (the value of `$name`) with the field at `path` set to `new`:
2874−/// a record's field, or the item of a list at an index it has. A name
2875−/// without a value, or one whose value is empty (a field a record doesn't
2876−/// have), becomes a record; any other value has no fields to set.
2877−fn with_field(
2878− value: Option<Value>,
2879− name: &str,
2880− path: &[&str],
2881− new: Value,
2882−) -> Result<Value, String> {
2883− let Some((field, rest)) = path.split_first() else {
2884− return Ok(new);
2885− };
2886− let inner = format!("{}.{}", name, field);
2887− match value {
2888− Some(Value::Record(fields)) => {
2889− let mut fields = fields.as_ref().clone();
2890− match fields.iter().position(|(key, _)| key == field) {
2891− Some(i) => {
2892− let old = std::mem::replace(&mut fields[i].1, Value::empty());
2893− fields[i].1 = with_field(Some(old), &inner, rest, new)?;
2894− }
2895− None => fields.push((field.to_string(), with_field(None, &inner, rest, new)?)),
2896− }
2897− Ok(Value::Record(Rc::new(fields)))
2898− }
2899− Some(Value::List(list)) => {
2900− let count = list.items.len();
2901− let Some(i) = field.parse::<usize>().ok().filter(|&i| i < count) else {
2902− return Err(format!(
2903− "`${}` is {}, so `.{}` isn't one of its items (they are `.0` to `.{}`)",
2904− name,
2905− Value::List(list).describe(),
2906− field,
2907− count.saturating_sub(1)
2908− ));
2909− };
2910− let mut items = list.items.as_ref().clone();
2911− let old = std::mem::replace(&mut items[i], Value::empty());
2912− items[i] = with_field(Some(old), &inner, rest, new)?;
2913− // Its items changed, so it no longer prints as written
2914− Ok(Value::list(items))
2915− }
2916− None => Ok(Value::Record(Rc::new(vec![(
2917− field.to_string(),
2918− with_field(None, &inner, rest, new)?,
2919− )]))),
2920− Some(value) if value.to_string().is_empty() => with_field(None, name, path, new),
2921− Some(value) => Err(format!(
2922− "`@let {}.{}` sets a field of a record, but `${}` is {} (`{}`), which has no fields",
2923− name,
2924− path.join("."),
2925− name,
2926− value.describe(),
2927− value
2928− )),
2929− }
2930−}
2931−
2932−/// What a verbatim directive holds (`@head`, `@style`, `@raw`): the rest
2933−/// of its line (`@style .a { color: red }`), or else its indented block.
2934−/// The two together are a syntax error, reported by the tree; the line
2935−/// wins.
2936−fn verbatim_content(node: &syntax::Node) -> String {
2937− match node.directive().map(|d| &d.args) {
2938− Some(DirectiveArgs::Text(Some(line))) => format!("{}\n", line.raw),
2939− _ => verbatim_text(&node.children),
2940− }
2941−}
2942−
2943−/// The text of a verbatim body (`@head`, `@style`, `@markdown`, `@raw`).
2944−fn verbatim_text(children: &[syntax::Node]) -> String {
2945− let mut text = String::new();
2946− for child in children {
2947− if let NodeKind::Verbatim(body) = &child.kind {
2948− text.push_str(&body.text);
2949− text.push('\n');
2950− }
2951− }
2952− text
2953−}
2954−
2955−// ---------------------------------------------------------------------------
2956−// @children replacement
2957−// ---------------------------------------------------------------------------
2958−
2959−fn replace_children_and_slots(
2960− nodes: Vec<Node>,
2961− caller_children: &[Node],
2962− slot_contents: &HashMap<String, Vec<Node>>,
2963−) -> Vec<Node> {
2964− let mut result = Vec::new();
2965− for node in nodes {
2966− match node {
2967− Node::Element(elem) if elem.kind == ElementKind::Children => {
2968− if caller_children.is_empty() && !elem.children.is_empty() {
2969− // Use @children's own children as default/fallback content
2970− result.extend(elem.children);
2971− } else {
2972− result.extend(caller_children.iter().cloned());
2973− }
2974− }
2975− Node::Element(elem) if matches!(&elem.kind, ElementKind::Slot(name) if !name.is_empty()) =>
2976− {
2977− if let ElementKind::Slot(ref name) = elem.kind {
2978− if let Some(content) = slot_contents.get(name) {
2979− result.extend(content.iter().cloned());
2980− }
2981− // If no content provided for this slot, use the slot's own children as default
2982− else if !elem.children.is_empty() {
2983− result.extend(elem.children);
2984− }
2985− }
2986− }
2987− Node::Element(mut elem) => {
2988− elem.children =
2989− replace_children_and_slots(elem.children, caller_children, slot_contents);
2990− result.push(Node::Element(elem));
2991− }
2992− other => result.push(other),
2993− }
2994− }
2995− result
2996−}
2997−
2998−// ---------------------------------------------------------------------------
2999−// Where @slot and @children are written
3000−// ---------------------------------------------------------------------------
3001−
3002−/// The files each `@include` line brought in, by the line's node id, with
3003−/// the include chain that leads to each.
3004−type IncludedBy = HashMap<usize, Vec<(Rc<Tree>, String)>>;
3005−
3006−/// The lines of the files an `@include` line brings in, and the include
3007−/// chain of each (for diagnostics).
3008−type Included<'a, 'f> = &'f dyn Fn(&syntax::Node) -> Vec<(&'a [syntax::Node], Option<&'a str>)>;
3009−
3010−/// Whether `name` is a function here: defined so far, or anywhere in the
3011−/// file and the files it includes.
3012−fn is_function(name: &str, ctx: &ParseContext) -> bool {
3013− ctx.env.function(name).is_some() || ctx.namespace.contains(name)
3014−}
3015−
3016−/// Whether `name` is one slot name: letters, digits, `-` and `_`,
3017−/// starting with a letter (like a function's name).
3018−fn is_slot_name(name: &str) -> bool {
3019− name.chars().next().is_some_and(char::is_alphabetic)
3020− && name
3021− .chars()
3022− .all(|c| c.is_alphanumeric() || c == '-' || c == '_')
3023−}
3024−
3025−/// What a `@slot` or `@children` line is written in.
3026−#[derive(Clone, Copy)]
3027−enum Place<'a> {
3028− /// The top of a file or of a function's body, or a built-in element
3029− /// (by its name).
3030− Element(Option<&'a str>),
3031− /// A call: its content.
3032− Call,
3033−}
3034−
3035−/// Where a line is, for [`slot_uses`].
3036−#[derive(Clone, Copy)]
3037−struct At<'a> {
3038− /// Inside a function's body.
3039− body: bool,
3040− place: Place<'a>,
3041− /// Outside a body: the call (and its line) whose content it is in.
3042− call: Option<(&'a str, usize)>,
3043− /// The include chain of the file it is in, when that isn't the file
3044− /// being compiled.
3045− file: Option<&'a str>,
3046−}
3047−
3048−impl At<'_> {
3049− /// The top of a file, or of a function's body.
3050− fn top(body: bool) -> Self {
3051− At {
3052− body,
3053− place: Place::Element(None),
3054− call: None,
3055− file: None,
3056− }
3057− }
3058−}
3059−
3060−/// What [`slot_uses`] knows about the names and files it walks.
3061−struct Scan<'a, 'f> {
3062− is_function: &'f dyn Fn(&str) -> bool,
3063− included: Included<'a, 'f>,
3064− /// Visit the bodies of the functions defined in the lines too.
3065− into_lets: bool,
3066−}
3067−
3068−/// A `@slot` or `@children` written in a file, and where.
3069−struct SlotUse<'a> {
3070− node: &'a syntax::Node,
3071− head: &'a syntax::Head,
3072− /// The text after it, which is a slot's name; `None` when it isn't
3073− /// the last head of its chain.
3074− text: Option<&'a syntax::Text>,
3075− /// Written inline in a line of text, `{@slot x}`.
3076− inline: bool,
3077− at: At<'a>,
3078−}
3079−
3080−impl SlotUse<'_> {
3081− fn is_slot(&self) -> bool {
3082− self.head.name == "slot"
3083− }
3084−
3085− /// The slot's name as written.
3086− fn name(&self) -> &str {
3087− self.text.map_or("", |t| t.raw.trim())
3088− }
3089−
3090− /// A `@slot NAME` that marks a place in a function's body (not one
3091− /// that fills a slot of a call).
3092− fn declares(&self) -> bool {
3093− self.is_slot() && !self.inline && !matches!(self.at.place, Place::Call)
3094− }
3095−}
3096−
3097−/// Where each `@slot` and `@children` in `block` is written. A `@slot`
3098−/// directly under a call (under its `@if`, `@else` and `@each` too) fills
3099−/// one of its slots; anywhere else in a function's body it declares one.
3100−/// An included file's lines are where its `@include` is.
3101−fn slot_uses<'a>(
3102− block: &'a [syntax::Node],
3103− at: At<'a>,
3104− scan: &Scan<'a, '_>,
3105− out: &mut Vec<SlotUse<'a>>,
3106−) {
3107− fn inline<'a>(
3108− text: &'a syntax::Text,
3109− node: &'a syntax::Node,
3110− at: At<'a>,
3111− scan: &Scan<'a, '_>,
3112− out: &mut Vec<SlotUse<'a>>,
3113− ) {
3114− for segment in &text.segments {
3115− if let Segment::Inline(inline_element) = segment {
3116− let head = &inline_element.head;
3117− if matches!(head.name.as_str(), "slot" | "children")
3118− && !(scan.is_function)(&head.name)
3119− {
3120− out.push(SlotUse {
3121− node,
3122− head,
3123− text: inline_element.text.as_ref(),
3124− inline: true,
3125− at,
3126− });
3127− }
3128− if let Some(text) = &inline_element.text {
3129− inline(text, node, at, scan, out);
3130− }
3131− }
3132− }
3133− }
3134− for node in block {
3135− match &node.kind {
3136− NodeKind::Directive(directive) => match &directive.args {
3137− DirectiveArgs::Let(def) if matches!(def.form, LetForm::Function(_)) => {
3138− if scan.into_lets {
3139− let top = At {
3140− file: at.file,
3141− ..At::top(true)
3142− };
3143− slot_uses(&node.children, top, scan, out);
3144− }
3145− }
3146− // A value's body is an error of its own
3147− DirectiveArgs::Let(_) => {}
3148− _ if directive.spec.body == BodyKind::Verbatim => {}
3149− // `@if`, `@else` and `@each` put their lines in place, and
3150− // `@include` its file's; the lines under a directive that
3151− // takes no body are its siblings
3152− _ => {
3153− for (lines, file) in (scan.included)(node) {
3154− slot_uses(lines, At { file, ..at }, scan, out);
3155− }
3156− slot_uses(&node.children, at, scan, out);
3157− }
3158− },
3159− NodeKind::Element(line) => {
3160− let mut at = at;
3161− let last = line.chain.len() - 1;
3162− for (i, head) in line.chain.iter().enumerate() {
3163− let text = if i == last { line.text.as_ref() } else { None };
3164− let function = (scan.is_function)(&head.name);
3165− if !function && matches!(head.name.as_str(), "slot" | "children") {
3166− out.push(SlotUse {
3167− node,
3168− head,
3169− text,
3170− inline: false,
3171− at,
3172− });
3173− } else if let Some(text) = text {
3174− inline(text, node, at, scan, out);
3175− }
3176− if function {
3177− at.place = Place::Call;
3178− if !at.body {
3179− at.call = Some((&head.name, node.span.line));
3180− }
3181− } else {
3182− at.place = Place::Element(Some(&head.name));
3183− }
3184− }
3185− slot_uses(&node.children, at, scan, out);
3186− }
3187− NodeKind::Text(text) => {
3188− inline(text, node, at, scan, out);
3189− slot_uses(&node.children, at, scan, out);
3190− }
3191− NodeKind::Blank | NodeKind::Comment | NodeKind::Verbatim(_) => {}
3192− }
3193− }
3194−}
3195−
3196−/// The slots a function's body declares, and whether it has a
3197−/// `@children`, when it is defined. The files its `@include` lines bring
3198−/// in count too: they are read now, since they run only at a call.
3199−fn declared_slots(body: &[syntax::Node], ctx: &mut ParseContext) -> (Vec<String>, bool) {
3200− let mut files = HashMap::new();
3201− read_includes(
3202− body,
3203− ctx.base_path.clone(),
3204− &mut Vec::new(),
3205− ctx,
3206− &mut files,
3207− );
3208− let included = |node: &syntax::Node| match files.get(&node.id) {
3209− Some(tree) => vec![(&tree.nodes[..], None)],
3210− None => Vec::new(),
3211− };
3212− let is_function = |name: &str| is_function(name, ctx);
3213− slots_of(body, &is_function, &included)
3214−}
3215−
3216−/// Read and parse the files the `@include` lines in `nodes` bring in (by
3217−/// a literal path, relative to `base`), and the files those include, by
3218−/// the node id of each `@include` line.
3219−fn read_includes(
3220− nodes: &[syntax::Node],
3221− base: Option<PathBuf>,
3222− stack: &mut Vec<PathBuf>,
3223− ctx: &mut ParseContext,
3224− files: &mut HashMap<usize, Rc<Tree>>,
3225−) {
3226− let mut includes = Vec::new();
3227− for node in nodes {
3228− node.walk(&mut |node| {
3229− if let Some(DirectiveArgs::Text(Some(path))) = node.directive().map(|d| &d.args)
3230− && node.is_directive("include")
3231− {
3232− includes.push((node.id, path.raw.clone()));
3233− }
3234− });
3235− }
3236− for (id, path) in includes {
3237− let path = path.trim_matches('"');
3238− if path.contains('$') {
3239− continue;
3240− }
3241− let resolved = match &base {
3242− Some(base) => base.join(path),
3243− None => PathBuf::from(path),
3244− };
3245− if stack.contains(&resolved) {
3246− continue;
3247− }
3248− let Ok(text) = ctx.read_file(&resolved) else {
3249− continue;
3250− };
3251− let tree = ctx.parse_tree(&text);
3252− stack.push(resolved.clone());
3253− let parent = resolved.parent().map(Path::to_path_buf);
3254− read_includes(&tree.nodes, parent, stack, ctx, files);
3255− stack.pop();
3256− files.insert(id, tree);
3257− }
3258−}
3259−
3260−/// The slots a function's body declares (`@slot NAME`, in order), and
3261−/// whether it has a `@children` for the content of a call. A `@slot`
3262−/// directly under a call in the body fills that call's slot instead, so
3263−/// `is_function` says which names are functions. The files the body
3264−/// includes aren't read.
3265−pub fn function_slots(
3266− body: &[syntax::Node],
3267− is_function: &dyn Fn(&str) -> bool,
3268−) -> (Vec<String>, bool) {
3269− slots_of(body, is_function, &|_| Vec::new())
3270−}
3271−
3272−fn slots_of<'a>(
3273− body: &'a [syntax::Node],
3274− is_function: &dyn Fn(&str) -> bool,
3275− included: Included<'a, '_>,
3276−) -> (Vec<String>, bool) {
3277− let scan = Scan {
3278− is_function,
3279− included,
3280− into_lets: false,
3281− };
3282− let mut uses = Vec::new();
3283− slot_uses(body, At::top(true), &scan, &mut uses);
3284− let mut slots: Vec<String> = Vec::new();
3285− for slot in uses.iter().filter(|u| u.declares()) {
3286− let name = slot.name();
3287− if is_slot_name(name) && !slots.iter().any(|s| s == name) {
3288− slots.push(name.to_string());
3289− }
3290− }
3291− let has_children = uses.iter().any(|u| !u.is_slot() && !u.inline);
3292− (slots, has_children)
3293−}
3294−
3295−/// The line as written, indented, when it is one physical line, so a
3296−/// column points into it.
3297−fn written_line(node: &syntax::Node) -> String {
3298− match node.line_count <= 1 {
3299− true => format!("{}{}", " ".repeat(node.indent), node.source),
3300− false => node.source.clone(),
3301− }
3302−}
3303−
3304−/// The lines of the files an `@include` line brought in when it ran, from
3305−/// `included_by`.
3306−fn ran_includes<'a>(
3307− included_by: &'a IncludedBy,
3308− node: &syntax::Node,
3309−) -> Vec<(&'a [syntax::Node], Option<&'a str>)> {
3310− match included_by.get(&node.id) {
3311− Some(files) => files
3312− .iter()
3313− .map(|(tree, chain)| (&tree.nodes[..], Some(chain.as_str())))
3314− .collect(),
3315− None => Vec::new(),
3316− }
3317−}
3318−
3319−/// Check where every `@slot` and `@children` of the file and the files it
3320−/// includes is written, whether or not it runs: a slot has one name, a
3321−/// function's body marks places with them, and a call fills its slots
3322−/// with `@slot` blocks directly under it. An included file's lines are
3323−/// where its `@include` is (in a body, under a call), so an `@include`
3324−/// that never ran leaves its file unchecked.
3325−fn check_slot_places(ctx: &mut ParseContext) {
3326− let trees = std::mem::take(&mut ctx.trees);
3327− let included_by = ctx.included_by.clone();
3328− let is_function = |name: &str| is_function(name, ctx);
3329− let scan = Scan {
3330− is_function: &is_function,
3331− included: &|node| ran_includes(&included_by, node),
3332− into_lets: true,
3333− };
3334− let mut uses = Vec::new();
3335− for (tree, _) in trees.iter().filter(|(_, chain)| chain.is_none()) {
3336− slot_uses(&tree.nodes, At::top(false), &scan, &mut uses);
3337− }
3338− let found: Vec<Diagnostic> = uses
3339− .iter()
3340− .filter_map(|slot| {
3341− let mut d = slot_problem(slot)?;
3342− if d.column.is_none() {
3343− d = d.column(slot.head.name_span.column);
3344− }
3345− d = d.source(written_line(slot.node));
3346− if let Some(file) = slot.at.file {
3347− d.message = format!("{}\n in {}", d.message, file);
3348− }
3349− Some(d)
3350− })
3351− .collect();
3352− ctx.diagnostics.extend(found);
3353− ctx.trees = trees;
3354−}
3355−
3356−/// What is wrong with a `@slot` or `@children` where it is written.
3357−fn slot_problem(slot: &SlotUse) -> Option<Diagnostic> {
3358− let line = slot.node.span.line;
3359− let what = if slot.is_slot() {
3360− match slot.name() {
3361− "" => "@slot".to_string(),
3362− name => format!("@slot {}", name),
3363− }
3364− } else {
3365− "@children".to_string()
3366− };
3367− if slot.inline {
3368− return Some(Diagnostic::error(
3369− code::MISPLACED_SLOT,
3370− line,
3371− format!(
3372− "{} goes on a line of its own: inline in text it marks and fills nothing",
3373− what
3374− ),
3375− ));
3376− }
3377− if let Some(list) = &slot.head.attrs {
3378− return Some(
3379− Diagnostic::error(
3380− code::UNEXPECTED_ARGUMENT,
3381− line,
3382− format!(
3383− "{} takes no attributes: it is replaced by content, so style the \
3384− element around it",
3385− what
3386− ),
3387− )
3388− .column(list.span.column),
3389− );
3390− }
3391− if slot.is_slot() {
3392− let name = slot.name();
3393− if name.is_empty() {
3394− return Some(Diagnostic::error(
3395− code::MISSING_ARGUMENT,
3396− line,
3397− "@slot needs a name: `@slot footer` (the caller's content without a \
3398− name goes where `@children` is)"
3399− .to_string(),
3400− ));
3401− }
3402− if !is_slot_name(name) {
3403− let joined = name.split_whitespace().collect::<Vec<_>>().join("-");
3404− let suggestion = is_slot_name(&joined).then_some(joined);
3405− let column = slot.text.map(|t| t.span.column);
3406− let d = Diagnostic::error(
3407− code::INVALID_SLOT_NAME,
3408− line,
3409− format!(
3410− "'{}' is not a slot name: a slot's name is one word of letters, digits, \
3411− `-` and `_`, starting with a letter, and its content goes on the lines \
3412− under it",
3413− name
3414− ),
3415− )
3416− .subject(name)
3417− .suggest(suggestion);
3418− return Some(match column {
3419− Some(column) => d.column(column),
3420− None => d,
3421− });
3422− }
3423− if matches!(slot.at.place, Place::Call) || slot.at.body {
3424− return None;
3425− }
3426− let message = match (slot.at.call, slot.at.place) {
3427− (Some((call, call_line)), Place::Element(Some(element))) => format!(
3428− "{} is inside @{}, so it fills nothing: a @slot block that fills a slot of \
3429− @{} (line {}) goes directly under the call",
3430− what, element, call, call_line
3431− ),
3432− _ => format!(
3433− "{} is outside a function's body: `@slot NAME` marks a place in a body \
3434− (`@let @name`), and directly under a call it fills one",
3435− what
3436− ),
3437− };
3438− return Some(Diagnostic::error(code::MISPLACED_SLOT, line, message));
3439− }
3440− if slot.at.body {
3441− return None;
3442− }
3443− let message = match slot.at.call {
3444− Some((call, _)) => format!(
3445− "@children is outside a function's body, so it stands for nothing: the content \
3446− for @{} is written directly under the call",
3447− call
3448− ),
3449− None => "@children is outside a function's body: it marks where a body puts the \
3450− content of each call"
3451− .to_string(),
3452− };
3453− Some(Diagnostic::error(code::MISPLACED_SLOT, line, message))
3454−}
3455−
3456−/// A `@slot NAME` block that fills a slot of a call.
3457−struct Filler<'a> {
3458− node: &'a syntax::Node,
3459− text: &'a syntax::Text,
3460− /// The include chain of the file it is in, when that isn't the file
3461− /// being compiled.
3462− file: Option<&'a str>,
3463−}
3464−
3465−/// Whether `@slot` is the built-in element here, and not a function
3466−/// defined so far that took its name.
3467−fn slot_is_built_in(ctx: &ParseContext) -> bool {
3468− ctx.env.function("slot").is_none()
3469−}
3470−
3471−/// The `@slot NAME` blocks directly under a call, in `block` (under its
3472−/// `@if`, `@else` and `@each` too, and in the files its `@include` lines
3473−/// brought in).
3474−fn fillers<'a>(
3475− block: &'a [syntax::Node],
3476− file: Option<&'a str>,
3477− included: &'a IncludedBy,
3478− out: &mut Vec<Filler<'a>>,
3479−) {
3480− for node in block {
3481− match &node.kind {
3482− NodeKind::Directive(directive)
3483− if matches!(directive.name(), "if" | "else" | "each") =>
3484− {
3485− fillers(&node.children, file, included, out);
3486− }
3487− NodeKind::Directive(directive) if directive.name() == "include" => {
3488− for (lines, file) in ran_includes(included, node) {
3489− fillers(lines, file, included, out);
3490− }
3491− }
3492− NodeKind::Element(line) if line.chain.len() == 1 && line.chain[0].name == "slot" => {
3493− if let Some(text) = &line.text {
3494− out.push(Filler { node, text, file });
3495− }
3496− }
3497− _ => {}
3498− }
3499− }
3500−}
3501−
3502−/// Whether `block`, the lines under a call, holds content other than
3503−/// `@slot` blocks (under `@if`, `@else` and `@each` too): text, an
3504−/// element, raw HTML, Markdown or an included file. For code that doesn't
3505−/// run.
3506−fn holds_content(block: &[syntax::Node], ctx: &ParseContext) -> bool {
3507− block.iter().any(|node| match &node.kind {
3508− NodeKind::Directive(directive) => match directive.name() {
3509− "if" | "else" | "each" => holds_content(&node.children, ctx),
3510− name => matches!(name, "raw" | "markdown" | "include"),
3511− },
3512− NodeKind::Element(line) => {
3513− line.chain[0].name != "slot" || !slot_is_built_in(ctx) || line.chain.len() > 1
3514− }
3515− NodeKind::Text(_) => true,
3516− _ => false,
3517− })
3518−}
3519−
3520−/// Check the `@slot NAME` blocks passed to each call of a line against
3521−/// the slots its function declares. `calls` has the function of each head
3522−/// of the chain that is a call.
3523−fn check_fillers(
3524− node: &syntax::Node,
3525− element: &syntax::ElementLine,
3526− calls: &[Option<(String, Rc<FnDef>)>],
3527− ctx: &mut ParseContext,
3528−) {
3529− if !slot_is_built_in(ctx) {
3530− return;
3531− }
3532− let included = ctx.included_by.clone();
3533− let last = element.chain.len() - 1;
3534− for (i, call) in calls.iter().enumerate() {
3535− let Some((name, function)) = call else {
3536− continue;
3537− };
3538− let mut found = Vec::new();
3539− if i == last {
3540− fillers(&node.children, None, &included, &mut found);
3541− } else if i + 1 == last
3542− && element.chain[last].name == "slot"
3543− && let Some(text) = &element.text
3544− {
3545− // `@card > @slot footer`
3546− found.push(Filler {
3547− node,
3548− text,
3549− file: None,
3550− });
3551− }
3552− for filler in found {
3553− let slot = filler.text.raw.trim();
3554− if !is_slot_name(slot) || function.slots.iter().any(|s| s == slot) {
3555− continue;
3556− }
3557− let mut d = unknown_slot(name, slot, &function.slots, filler.text.span.line)
3558− .column(filler.text.span.column)
3559− .source(written_line(filler.node));
3560− if let Some(file) = filler.file {
3561− d.message = format!("{}\n in {}", d.message, file);
3562− }
3563− ctx.push_once(d);
3564− }
3565− }
3566−}
3567−
3568−/// A `@slot NAME` block for a slot the function doesn't declare.
3569−fn unknown_slot(function: &str, slot: &str, slots: &[String], line: usize) -> Diagnostic {
3570− let candidates: Vec<&str> = slots.iter().map(String::as_str).collect();
3571− let suggestion = suggest_closest(slot, &candidates);
3572− let message = match (slots.is_empty(), suggestion) {
3573− (true, _) => format!(
3574− "@{} has no slot '{}': its body declares no slots (`@slot NAME`)",
3575− function, slot
3576− ),
3577− (false, Some(close)) => format!(
3578− "@{} has no slot '{}', did you mean '{}'? (its slots: {})",
3579− function,
3580− slot,
3581− close,
3582− slots.join(", ")
3583− ),
3584− (false, None) => format!(
3585− "@{} has no slot '{}' (its slots: {})",
3586− function,
3587− slot,
3588− slots.join(", ")
3589− ),
3590− };
3591− Diagnostic::error(code::UNKNOWN_SLOT, line, message)
3592− .subject(slot)
3593− .suggest(suggestion)
3594−}
3595−
3596−/// Content passed to a function whose body has no `@children`.
3597−fn no_children(function: &str, line: usize, column: Option<usize>) -> Diagnostic {
3598− let d = Diagnostic::error(
3599− code::UNEXPECTED_CONTENT,
3600− line,
3601− format!(
3602− "@{0} takes no content: its body has no `@children`, so the text and lines \
3603− passed to it would be dropped (pass text as a parameter, `@{0} [name value]`, \
3604− or add `@children` to the body)",
3605− function
3606− ),
3607− )
3608− .subject(function);
3609− match column {
3610− Some(column) => d.column(column),
3611− None => d,
3612− }
3613−}
3614−
3615−// ---------------------------------------------------------------------------
3616−// Element parsing
3617−// ---------------------------------------------------------------------------
3618−
3619−/// Build the element for `@name [attrs] text` (on its own line, in a chain,
3620−/// or inline in text).
3621−fn parse_single_element(
3622− head: &syntax::Head,
3623− text: Option<&syntax::Text>,
3624− line_num: usize,
3625− ctx: &mut ParseContext,
3626−) -> Result<Element, ParseError> {
3627− let kind = parse_element_kind(&head.name, line_num, ctx)?;
3628− let mut attrs = head.attrs.as_ref().map_or_else(Vec::new, |list| {
3629− parse_attr_list(&list.attrs, line_num, ctx, true, &[])
3630− });
3631−
3632− // The leading argument: for an element whose row names a leading
3633− // attribute (`@link`'s href, `@image`'s src, `@form`'s action, ...),
3634− // the first token of the text fills it, split before anything is
3635− // filled in, and the rest is content (an error on an element without
3636− // content). `@slot`'s whole text is its name. Any other element's text
3637− // is content, parsed like any line of text, as in `@el [padding 8]
3638− // Hello` or `@h2 Meet {@text htmlang}`; its layout decides how it
3639− // combines with the lines under it.
3640− let mut children = Vec::new();
3641− let mut argument = None;
3642− let leading = kind.arg().attributes();
3643− match text {
3644− Some(text) if !leading.is_empty() => {
3645− let (token, rest) = text.split_leading();
3646− let given = attrs
3647− .iter()
3648− .find(|a| a.html && leading.contains(&a.key.as_str()))
3649− .map(|a| (a.key.clone(), a.value.clone().unwrap_or_default()));
3650− if let Some((key, value)) = given {
3651− // The attribute wins; the text is content, as if the
3652− // element had no leading argument
3653− ctx.push_once(leading_twice(&kind, &token, &key, &value, text, ctx));
3654− if !takes_no_text(&kind) {
3655− children.push(Node::Text(text_segments(text, ctx)));
3656− }
3657− } else if let Some(d) = bad_leading_token(&kind, &token, &text.raw, ctx) {
3658− // Nothing is taken as the argument; the line is content
3659− ctx.push_once(d);
3660− if !takes_no_text(&kind) {
3661− children.push(Node::Text(text_segments(text, ctx)));
3662− }
3663− } else {
3664− let column = Some(token.span.column);
3665− if let Some(d) = text_as_url(&kind, &token, ctx) {
3666− ctx.push_once(d);
3667− }
3668− argument = Some(
3669− ctx.fill_value(&token.raw, text.span.line, column, Sink::Text)
3670− .0,
3671− );
3672− if let Some(rest) = rest {
3673− if let Some(d) = chain_after_argument(&kind, &token.raw, &rest, ctx) {
3674− ctx.push_once(d);
3675− }
3676− if takes_no_text(&kind) {
3677− let d = after_the_leading_argument(&kind, &token.raw, &rest);
3678− let d = at_attribute(d, Some(rest.span.column), ctx);
3679− ctx.push_once(d);
3680− } else {
3681− children.push(Node::Text(text_segments(&rest, ctx)));
3682− }
3683− }
3684− }
3685− }
3686− Some(text) if matches!(kind, ElementKind::Slot(_)) => {
3687− argument =
3688− Some(ctx.interpolate_text(&text.raw, text.span.line, Some(text.span.column)));
3689− }
3690− Some(text) => children.push(Node::Text(text_segments(text, ctx))),
3691− // `@link [href=/about]`: the attribute is the leading argument, so
3692− // both forms compile the same (`@image [src=a.svg, inline]`). Not
3693− // for `@source`, whose attribute depends on where it is.
3694− None if leading.len() == 1 => {
3695− if let Some(i) = attrs.iter().position(|a| a.html && a.key == leading[0]) {
3696− argument = Some(attrs.remove(i).value.unwrap_or_default());
3697− }
3698− }
3699− None => {}
3700− }
3701−
3702− // For @slot, the argument is the slot name
3703− let kind = if let ElementKind::Slot(_) = kind {
3704− ElementKind::Slot(argument.clone().unwrap_or_default())
3705− } else {
3706− kind
3707− };
3708−
3709− Ok(Element {
3710− kind,
3711− attrs,
3712− argument,
3713− children,
3714− line_num,
3715− function: None,
3716− })
3717−}
3718−
3719−/// Whether `node` or a line inside it calls `@name` outside any `@if`
3720−/// (in a chain, or inline in text).
3721−fn calls_unguarded(node: &syntax::Node, name: &str) -> bool {
3722− if node.is_directive("if") || node.is_directive("else") {
3723− return false;
3724− }
3725− let text_calls = |text: &syntax::Text| {
3726− text.segments
3727− .iter()
3728− .any(|s| matches!(s, Segment::Inline(inline) if inline.head.name == name))
3729− };
3730− let here = match &node.kind {
3731− NodeKind::Element(element) => {
3732− element.chain.iter().any(|head| head.name == name)
3733− || element.text.as_ref().is_some_and(text_calls)
3734− }
3735− NodeKind::Text(text) => text_calls(text),
3736− _ => false,
3737− };
3738− here || node
3739− .children
3740− .iter()
3741− .any(|child| calls_unguarded(child, name))
3742−}
3743−
3744−/// `@td [padding 8] @children`: `@children` and `@slot NAME` mark where a
3745−/// call's content goes only on a line of their own; after an element's
3746−/// attributes, or in a verbatim body, they are text.
3747−fn marker_in_text(node: &syntax::Node) -> Option<Diagnostic> {
3748− let is_marker = |text: &str| {
3749− let text = text.trim();
3750− text == "@children" || text == "@slot" || text.starts_with("@slot ")
3751− };
3752− let mut line = node.span.line;
3753− let mut source = written_line(node);
3754− let (marker, message) = match &node.kind {
3755− NodeKind::Element(element) => {
3756− let text = element.text.as_ref()?;
3757− if !is_marker(&text.raw) {
3758− return None;
3759− }
3760− let name = &element.chain.last()?.name;
3761− let marker = text.raw.trim().to_string();
3762− let message = format!(
3763− "`{marker}` after @{name}'s attributes is text: it marks where a call's content \
3764− goes only on a line of its own, so write it on the next line, indented under \
3765− @{name}"
3766− );
3767− (marker, message)
3768− }
3769− NodeKind::Verbatim(verbatim) if verbatim.escaped => {
3770− let (i, written) = verbatim
3771− .text
3772− .lines()
3773− .enumerate()
3774− .find(|(_, l)| is_marker(l))?;
3775− let marker = written.trim().to_string();
3776− line += i;
3777− source = written.to_string();
3778− let message = format!(
3779− "`{marker}` in a verbatim body is text: the body is written as it is, so it can't \
3780− hold a call's content (pass the text as a parameter instead)"
3781− );
3782− (marker, message)
3783− }
3784− _ => return None,
3785− };
3786− Some(
3787− Diagnostic::error(code::MISPLACED_SLOT, line, message)
3788− .subject(marker)
3789− .source(source),
3790− )
3791−}
3792−
3793−/// A first word that can't be a leading argument: an inline element
3794−/// (`@link {@b x} y`), or a quote that isn't closed (`@link "a b`).
3795−fn bad_leading_token(
3796− kind: &ElementKind,
3797− token: &syntax::Arg,
3798− text: &str,
3799− ctx: &ParseContext,
3800−) -> Option<Diagnostic> {
3801− let what = leading_name(kind);
3802− let name = kind.name();
3803− let message = if token.raw.starts_with("{@") {
3804− format!(
3805− "@{0} takes its {1} first, before any text: write `@{0} VALUE {2}`, or give it as \
3806− `[{1}=VALUE]`",
3807− name,
3808− what,
3809− text.trim()
3810− )
3811− } else if token.raw.starts_with('"') && syntax::quoted_string(&token.raw).is_none() {
3812− format!(
3813− "@{}'s {} starts with a `\"` that isn't closed: close it (`\"...\"`), or write \
3814− `\\\"` for a quote in the value",
3815− name, what
3816− )
3817− } else {
3818− return None;
3819− };
3820− let d = Diagnostic::error(code::UNEXPECTED_ARGUMENT, token.span.line, message)
3821− .subject(token.raw.clone());
3822− Some(at_attribute(d, Some(token.span.column), ctx))
3823−}
3824−
3825−/// A first word taken as a URL that reads as text: a word with a capital
3826−/// and nothing a URL or a file name has, as in `@link [hx-get=/panel] Open
3827−/// panel`, whose href would be `Open`. It still is (a relative URL can be
3828−/// such a word), with a warning.
3829−fn text_as_url(kind: &ElementKind, token: &syntax::Arg, ctx: &ParseContext) -> Option<Diagnostic> {
3830− const URLS: &[&str] = &["href", "src", "srcset", "action", "data"];
3831− let word = token.raw.as_str();
3832− let reads_as_text = word.starts_with(char::is_uppercase)
3833− && !word.contains([
3834− '/', '.', ':', '#', '?', '=', '&', '%', '~', '$', '{', '\\', '"',
3835− ]);
3836− if !reads_as_text || !kind.arg().attributes().iter().any(|a| URLS.contains(a)) {
3837− return None;
3838− }
3839− let name = kind.name();
3840− let attr = leading_name(kind);
3841− let text = if takes_no_text(kind) {
3842− String::new()
3843− } else {
3844− format!(": write the {attr} before the text, or put the text on the lines under it")
3845− };
3846− let message = format!(
3847− "@{name} takes '{word}', its first word, as its {attr}{text}. A relative URL that \
3848− starts with a capital is written `./{word}`"
3849− );
3850− let d = Diagnostic::warning(code::TEXT_AS_URL, token.span.line, message).subject(word);
3851− Some(at_attribute(d, Some(token.span.column), ctx))
3852−}
3853−
3854−/// `@link /a > @image logo.png`: a `>` chains only after an element's
3855−/// name or its `[attributes]`, so after a leading argument it is text.
3856−/// Said when what follows names an element or a function.
3857−fn chain_after_argument(
3858− kind: &ElementKind,
3859− token: &str,
3860− rest: &syntax::Text,
3861− ctx: &ParseContext,
3862−) -> Option<Diagnostic> {
3863− let after = rest.raw.strip_prefix('>')?;
3864− let name_start = after.trim_start().strip_prefix('@')?;
3865− if after.len() == after.trim_start().len() {
3866− return None;
3867− }
3868− let name: String = name_start
3869− .chars()
3870− .take_while(|c| c.is_ascii_alphanumeric() || *c == '-')
3871− .collect();
3872− if ElementKind::from_name(&name).is_none() && ctx.env.function(&name).is_none() {
3873− return None;
3874− }
3875− let attr = leading_name(kind);
3876− let d = Diagnostic::warning(
3877− code::UNEXPECTED_ARGUMENT,
3878− rest.span.line,
3879− format!(
3880− "`{}` after @{}'s {} is text, not a chain: `>` chains after an element's name or \
3881− its [attributes], so write `@{} [{}={}] {}`",
3882− rest.raw.trim_end(),
3883− kind.name(),
3884− attr,
3885− kind.name(),
3886− attr,
3887− token,
3888− rest.raw.trim_end()
3889− ),
3890− )
3891− .subject(rest.raw.trim_end());
3892− Some(at_attribute(d, Some(rest.span.column), ctx))
3893−}
3894−
3895−/// A leading argument given twice, as the first token and as its
3896−/// attribute: `@link [href=/a] About`.
3897−fn leading_twice(
3898− kind: &ElementKind,
3899− token: &syntax::Arg,
3900− key: &str,
3901− value: &str,
3902− text: &syntax::Text,
3903− ctx: &ParseContext,
3904−) -> Diagnostic {
3905− let name = kind.name();
3906− let what = leading_name(kind);
3907− // The value as one token: quoted when it is empty or has a space in it
3908− let value = if !value.is_empty() && syntax::leading_token_len(value) == value.len() {
3909− value.to_string()
3910− } else {
3911− format!("\"{}\"", value.replace('\\', "\\\\").replace('"', "\\\""))
3912− };
3913− let written = if takes_no_text(kind) {
3914− format!("@{} {}", name, value)
3915− } else {
3916− format!("@{} {} {}", name, value, text.raw)
3917− };
3918− let d = Diagnostic::error(
3919− code::DUPLICATE_ATTRIBUTE,
3920− text.span.line,
3921− format!(
3922− "@{} takes its first word '{}' as its {}, and it also has {}=: give it once, \
3923− as `{}`",
3924− name, token.raw, what, key, written
3925− ),
3926− )
3927− .subject(token.raw.clone());
3928− at_attribute(d, Some(token.span.column), ctx)
3929−}
3930−
3931−/// The attribute an element's leading argument fills, for messages.
3932−fn leading_name(kind: &ElementKind) -> &'static str {
3933− match kind.arg() {
3934− TagArg::Source => "srcset in @picture or src elsewhere",
3935− arg => arg.attribute(false).unwrap_or("argument"),
3936− }
3937−}
3938−
3939−/// Whether text after an element's leading argument has nowhere to go:
3940−/// an element without content (`@image`, `@source`, ...), or `@optgroup`,
3941−/// which holds only `@option` lines, so `@optgroup Citrus fruits` would
3942−/// otherwise make `Citrus` the label and drop `fruits`.
3943−fn takes_no_text(kind: &ElementKind) -> bool {
3944− kind.layout() == Layout::Void || kind.is_tag("optgroup")
3945−}
3946−
3947−/// Text after the leading argument of an element without content:
3948−/// `@image logo.png Our logo`.
3949−fn after_the_leading_argument(kind: &ElementKind, token: &str, rest: &syntax::Text) -> Diagnostic {
3950− let name = kind.name();
3951− let attr = leading_name(kind);
3952− let alt = if matches!(kind, ElementKind::Image) || kind.is_tag("area") {
3953− " For a text alternative, write `alt=...`."
3954− } else {
3955− ""
3956− };
3957− let holds = if kind.layout() == Layout::Void {
3958− "it has no content"
3959− } else {
3960− "it holds only the elements on the lines under it"
3961− };
3962− let bare = syntax::quoted_string(token).unwrap_or(token);
3963− Diagnostic::error(
3964− code::UNEXPECTED_ARGUMENT,
3965− rest.span.line,
3966− format!(
3967− "@{0} takes one word after its attributes, its {1} ('{2}'), and {5}, so '{3}' \
3968− would go nowhere. A value with a space in it is quoted: `\"{6} {3}\"`.{4}",
3969− name, attr, token, rest.raw, alt, holds, bare
3970− ),
3971− )
3972− .subject(rest.raw.clone())
3973−}
3974−
3975−/// The element named `name`, or an "unknown element" error that suggests
3976−/// the closest element, directive or function.
3977−fn parse_element_kind(
3978− name: &str,
3979− line_num: usize,
3980− ctx: &mut ParseContext,
3981−) -> Result<ElementKind, ParseError> {
3982− if let Some(kind) = ElementKind::from_name(name) {
3983− return Ok(kind);
3984− }
3985− // A known name in a place it can't go: say why instead of suggesting
3986− // the name itself.
3987− let misplaced = if crate::ast::directive(name).is_some() {
3988− Some(format!(
3989− "unknown element @{}: @{} is a directive, which goes at the start of its own line",
3990− name, name
3991− ))
3992− } else if ctx.env.bundle(name).is_some() {
3993− Some(format!(
3994− "unknown element @{}: '{}' is an attribute bundle, used as `[${}]` \
3995− (a function is defined with `@let @{}`)",
3996− name, name, name, name
3997− ))
3998− } else if ctx.env.value(name).is_some() {
3999− Some(format!(
4000− "unknown element @{}: '{}' is a value, used as `${}` \
4001− (a function is defined with `@let @{}`)",
4002− name, name, name, name
4003− ))
4004− } else if ctx.namespace.contains(name) {
4005− ctx.used_functions.insert(name.to_string());
4006− Some(format!(
4007− "unknown element @{}: the function @{} isn't visible here. A definition is \
4008− visible from its line to the end of its block, and a function's body sees what \
4009− is defined above the function, so define @{} above this line, outside the block \
4010− it is in",
4011− name, name, name
4012− ))
4013− } else if matches!(name, "svg" | "math" | "template") {
4014− Some(format!(
4015− "unknown element @{}: htmlang doesn't write <{}>; put its markup in the page with \
4016− @raw{}",
4017− name,
4018− name,
4019− if name == "svg" {
4020− " (or an SVG file with `@image [inline] file.svg`)"
4021− } else {
4022− ""
4023− }
4024− ))
4025− } else {
4026− None
4027− };
4028− if let Some(message) = misplaced {
4029− return Err(Diagnostic::error(code::UNKNOWN_ELEMENT, line_num, message).subject(name));
4030− }
4031− let all_known: Vec<&str> = ElementKind::all_names()
4032− .chain(DIRECTIVES.iter().map(|d| d.name))
4033− .collect();
4034− // An HTML element htmlang writes under its own name (`@a` is `@link`).
4035− let written_otherwise = crate::ast::HTML_NAMES_WRITTEN_OTHERWISE
4036− .iter()
4037− .find(|(html, _)| *html == name)
4038− .map(|(_, htmlang)| *htmlang);
4039− let closest = written_otherwise.or_else(|| suggest_closest(name, &all_known));
4040− let mut message = match (closest, written_otherwise) {
4041− (Some(closest), Some(_)) => format!(
4042− "unknown element @{}, did you mean @{}? (@{} writes <{}>)",
4043− name, closest, closest, name
4044− ),
4045− (Some(closest), None) => format!("unknown element @{}, did you mean @{}?", name, closest),
4046− (None, _) => format!("unknown element @{}", name),
4047− };
4048− let function = suggest_fn_name(name, ctx);
4049− if let Some(function) = &function {
4050− message = format!("{}, or did you mean @{}?", message, function);
4051− }
4052− Err(Diagnostic::error(code::UNKNOWN_ELEMENT, line_num, message)
4053− .subject(name)
4054− .suggest(closest.map(str::to_string).or(function)))
4055−}
4056−
4057−/// Format include/import stack as a readable chain for error messages.
4058−fn format_include_chain(stack: &[PathBuf]) -> String {
4059− stack
4060− .iter()
4061− .map(|p| {
4062− p.file_name()
4063− .unwrap_or_default()
4064− .to_string_lossy()
4065− .to_string()
4066− })
4067− .collect::<Vec<_>>()
4068− .join(" → ")
4069−}
4070−
4071−/// Levenshtein distance with a rolling two-row buffer (O(min(a,b)) memory) and an
4072−/// early-exit cutoff: if every cell in a row exceeds `cutoff`, no further cell can
4073−/// be <= `cutoff`, so we return `cutoff + 1` immediately. Used for typo-suggestion
4074−/// hot paths where we only care about distances <= 2.
4075−fn levenshtein_bounded(a: &[char], b: &[char], cutoff: usize) -> usize {
4076− let (a, b) = if a.len() > b.len() { (b, a) } else { (a, b) };
4077− if b.len() - a.len() > cutoff {
4078− return cutoff + 1;
4079− }
4080− if a.is_empty() {
4081− return b.len();
4082− }
4083−
4084− let mut prev: Vec<usize> = (0..=a.len()).collect();
4085− let mut curr: Vec<usize> = vec![0; a.len() + 1];
4086−
4087− for (j, &bc) in b.iter().enumerate() {
4088− curr[0] = j + 1;
4089− let mut row_min = curr[0];
4090− for (i, &ac) in a.iter().enumerate() {
4091− let cost = if ac == bc { 0 } else { 1 };
4092− curr[i + 1] = (prev[i + 1] + 1).min(curr[i] + 1).min(prev[i] + cost);
4093− row_min = row_min.min(curr[i + 1]);
4094− }
4095− if row_min > cutoff {
4096− return cutoff + 1;
4097− }
4098− std::mem::swap(&mut prev, &mut curr);
4099− }
4100− prev[a.len()]
4101−}
4102−
4103−fn suggest_closest<'a>(input: &str, candidates: &[&'a str]) -> Option<&'a str> {
4104− let input_chars: Vec<char> = input.chars().collect();
4105− let max_allowed = 2usize.min(input_chars.len().saturating_sub(1));
4106− let mut best = None;
4107− let mut best_dist = usize::MAX;
4108− for &candidate in candidates {
4109− // Cheap length-based prune before allocating chars.
4110− let clen = candidate.chars().count();
4111− let diff = clen.abs_diff(input_chars.len());
4112− if diff > max_allowed {
4113− continue;
4114− }
4115− let cand_chars: Vec<char> = candidate.chars().collect();
4116− let dist = levenshtein_bounded(&input_chars, &cand_chars, max_allowed);
4117− if dist < best_dist && dist <= max_allowed {
4118− best_dist = dist;
4119− best = Some(candidate);
4120− }
4121− }
4122− best
4123−}
4124−
4125−/// Suggest the closest user-defined function name for typos, from the
4126−/// functions defined so far and those defined anywhere in the file.
4127−fn suggest_fn_name(input: &str, ctx: &ParseContext) -> Option<String> {
4128− let input_chars: Vec<char> = input.chars().collect();
4129− let max_allowed = 2usize.min(input_chars.len().saturating_sub(1));
4130− let mut best: Option<(usize, &String)> = None;
4131− let visible: Vec<&String> = ctx.defined_functions.keys().collect();
4132− for name in visible.into_iter().chain(ctx.namespace.iter()) {
4133− let nlen = name.chars().count();
4134− if nlen.abs_diff(input_chars.len()) > max_allowed {
4135− continue;
4136− }
4137− let name_chars: Vec<char> = name.chars().collect();
4138− let dist = levenshtein_bounded(&input_chars, &name_chars, max_allowed);
4139− if dist <= max_allowed && best.is_none_or(|b| (dist, name) < b) {
4140− best = Some((dist, name));
4141− }
4142− }
4143− best.map(|(_, name)| name.clone())
4144−}
4145−
4146−/// Suggest the closest variable name for undefined `$var` references.
4147−fn suggest_var_name(input: &str, vars: &[&str]) -> Option<String> {
4148− let input_chars: Vec<char> = input.chars().collect();
4149− let max_allowed = 2usize.min(input_chars.len().saturating_sub(1));
4150− let mut best: Option<String> = None;
4151− let mut best_dist = usize::MAX;
4152− let mut vars = vars.to_vec();
4153− // The same answer every time, whatever the order of the names
4154− vars.sort_unstable();
4155− for name in vars {
4156− let nlen = name.chars().count();
4157− if nlen.abs_diff(input_chars.len()) > max_allowed {
4158− continue;
4159− }
4160− let name_chars: Vec<char> = name.chars().collect();
4161− let dist = levenshtein_bounded(&input_chars, &name_chars, max_allowed);
4162− if dist < best_dist && dist <= max_allowed {
4163− best_dist = dist;
4164− best = Some(name.to_string());
4165− }
4166− }
4167− best
4168−}
4169−
4170−// ---------------------------------------------------------------------------
4171−// Attribute parsing
4172−// ---------------------------------------------------------------------------
4173−
4174−/// The quoted strings of a CSS value, without their quotes.
4175−fn css_strings(value: &str) -> Vec<&str> {
4176− let mut strings = Vec::new();
4177− let mut start = None;
4178− let mut escaped = false;
4179− for (i, c) in value.char_indices() {
4180− match (c, start) {
4181− _ if escaped => escaped = false,
4182− ('\\', Some(_)) => escaped = true,
4183− ('"', None) => start = Some(i + 1),
4184− ('"', Some(from)) => {
4185− strings.push(&value[from..i]);
4186− start = None;
4187− }
4188− _ => {}
4189− }
4190− }
4191− strings
4192−}
4193−
4194−/// An `if(...)` in a CSS value that isn't CSS's if(): CSS writes each
4195−/// branch `CONDITION: VALUE`, so an if() without a `:` is something else.
4196−/// Quoted CSS strings are text, not calls.
4197−fn not_css_if(value: &str) -> Option<&str> {
4198− let mut quote = None;
4199− let mut prev = None;
4200− let mut chars = value.char_indices();
4201− while let Some((at, c)) = chars.next() {
4202− match quote {
4203− Some(_) if c == '\\' => {
4204− chars.next();
4205− }
4206− Some(q) if c == q => quote = None,
4207− Some(_) => {}
4208− None if matches!(c, '"' | '\'') => quote = Some(c),
4209− None => {
4210− let word_before =
4211− prev.is_some_and(|p: char| p.is_alphanumeric() || matches!(p, '-' | '_'));
4212− if !word_before && value[at..].starts_with("if(") {
4213− let mut depth = 0;
4214− let close = value[at + 2..].char_indices().find_map(|(i, c)| {
4215− match c {
4216− '(' => depth += 1,
4217− ')' => depth -= 1,
4218− _ => {}
4219− }
4220− (depth == 0).then_some(at + 2 + i)
4221− });
4222− let end = close.map_or(value.len(), |c| c + 1);
4223− if !value[at + 3..end].contains(':') {
4224− return Some(&value[at..end]);
4225− }
4226− }
4227− }
4228− }
4229− prev = Some(c);
4230− }
4231− None
4232−}
4233−
4234−/// Why a CSS value can't be written into a rule as it is, whatever it
4235−/// means: a `;` (outside parentheses, where CSS's own `if()` uses it), a
4236−/// `{` or a `}` would end the declaration or the rule, and an unclosed
4237−/// quote or parenthesis would run on into the rules after it. Quoted
4238−/// strings are text, and a backslash escapes the character after it, as
4239−/// in CSS. A `</style` anywhere, even in a string, would end the page's
4240−/// `<style>` element and start HTML.
4241−fn css_breakout(value: &str) -> Option<&'static str> {
4242− if value.to_ascii_lowercase().contains("</style") {
4243− return Some("a `</style`, which would end the page's style element");
4244− }
4245− let mut quote = None;
4246− let mut depth = 0usize;
4247− let mut chars = value.chars();
4248− while let Some(c) = chars.next() {
4249− match (quote, c) {
4250− (_, '\\') => {
4251− chars.next();
4252− }
4253− (Some(q), c) if c == q => quote = None,
4254− (Some(_), _) => {}
4255− (None, '"' | '\'') => quote = Some(c),
4256− (None, '(') => depth += 1,
4257− (None, ')') if depth == 0 => return Some("a `)` that closes nothing"),
4258− (None, ')') => depth -= 1,
4259− (None, ';') if depth == 0 => return Some("a `;`, which would end the declaration"),
4260− (None, '{' | '}') => return Some("a `{` or `}`, which would end the CSS rule"),
4261− _ => {}
4262− }
4263− }
4264− match (quote, depth) {
4265− (Some('"'), _) => Some("a `\"` that isn't closed"),
4266− (Some(_), _) => Some("a `'` that isn't closed"),
4267− (None, 0) => None,
4268− (None, _) => Some("a `(` that isn't closed"),
4269− }
4270−}
4271−
4272−/// The hex colors of a CSS value that don't have 3, 4, 6 or 8 hex
4273−/// digits. A `#` word in a CSS value is a color, except inside `url(...)`
4274−/// and quoted strings.
4275−fn bad_hex_colors(value: &str) -> Vec<&str> {
4276− let mut bad = Vec::new();
4277− let mut quote = None;
4278− let mut in_url = 0usize;
4279− let mut depth = 0usize;
4280− let mut chars = value.char_indices().peekable();
4281− while let Some((at, c)) = chars.next() {
4282− match (quote, c) {
4283− (_, '\\') => {
4284− chars.next();
4285− }
4286− (Some(q), c) if c == q => quote = None,
4287− (Some(_), _) => {}
4288− (None, '"' | '\'') => quote = Some(c),
4289− (None, '(') => {
4290− depth += 1;
4291− if value[..at].ends_with("url") && in_url == 0 {
4292− in_url = depth;
4293− }
4294− }
4295− (None, ')') => {
4296− if in_url == depth {
4297− in_url = 0;
4298− }
4299− depth = depth.saturating_sub(1);
4300− }
4301− (None, '#') if in_url == 0 => {
4302− let end = value[at + 1..]
4303− .find(|c: char| !(c.is_alphanumeric() || c == '-' || c == '_'))
4304− .map_or(value.len(), |n| at + 1 + n);
4305− let hex = &value[at + 1..end];
4306− if !(matches!(hex.len(), 3 | 4 | 6 | 8)
4307− && hex.chars().all(|c| c.is_ascii_hexdigit()))
4308− {
4309− bad.push(&value[at..end]);
4310− }
4311− }
4312− _ => {}
4313− }
4314− }
4315− bad
4316−}
4317−
4318−/// A diagnostic about an attribute, with its column and source line when
4319−/// it is on the line being evaluated.
4320−fn at_attribute(diagnostic: Diagnostic, column: Option<usize>, ctx: &ParseContext) -> Diagnostic {
4321− match (&ctx.current_source, column) {
4322− ((current, Some(text)), Some(column)) if *current == diagnostic.line => {
4323− diagnostic.column(column).source(text.clone())
4324− }
4325− _ => diagnostic,
4326− }
4327−}
4328−
4329−/// Check a style's value. Values go to the CSS as written, so only what
4330−/// can't be wrong in any CSS is checked: a value that would break out of
4331−/// its rule is an error (and it is left out); a hex color without 3, 4, 6
4332−/// or 8 digits, an `if()` that isn't CSS's and a quoted font stack are
4333−/// warnings. Returns whether the value can be written.
4334−fn check_css_value(
4335− attr: &Attribute,
4336− base: &str,
4337− line: usize,
4338− column: Option<usize>,
4339− ctx: &mut ParseContext,
4340−) -> bool {
4341− let Some(value) = &attr.value else {
4342− return true;
4343− };
4344− if let Some(reason) = css_breakout(value) {
4345− let diagnostic = Diagnostic::error(
4346− code::INVALID_VALUE,
4347− line,
4348− format!(
4349− "the value of '{}' has {}: `{}` can't be written into the page's CSS",
4350− attr.key, reason, value
4351− ),
4352− )
4353− .subject(value.as_str());
4354− ctx.diagnostics.push(at_attribute(diagnostic, column, ctx));
4355− return false;
4356− }
4357− if crate::vocab::is_custom_property(base) {
4358− return true;
4359− }
4360−
4361− let warn = |ctx: &mut ParseContext, diagnostic: Diagnostic| {
4362− let diagnostic = at_attribute(diagnostic, column, ctx);
4363− ctx.diagnostics.push(diagnostic);
4364− };
4365− // In CSS, a quoted font-family is one family, commas and all
4366− if base == "font-family"
4367− && let Some(family) = css_strings(value).into_iter().find(|s| s.contains(','))
4368− {
4369− let stack = family
4370− .split(',')
4371− .map(str::trim)
4372− .collect::<Vec<_>>()
4373− .join("\\, ");
4374− warn(
4375− ctx,
4376− Diagnostic::warning(
4377− code::INVALID_VALUE,
4378− line,
4379− format!(
4380− "font-family \"{}\" is one family, whose name has a comma in it: \
4381− for a font stack, write `font-family {}`",
4382− family, stack
4383− ),
4384− )
4385− .subject(format!("\"{}\"", family))
4386− .suggest(Some(stack)),
4387− );
4388− }
4389− if let Some(call) = not_css_if(value) {
4390− warn(
4391− ctx,
4392− Diagnostic::warning(
4393− code::INVALID_VALUE,
4394− line,
4395− format!(
4396− "'{}' is not CSS's if(), whose branches are written \
4397− `if(CONDITION: VALUE; else: VALUE)`",
4398− call
4399− ),
4400− )
4401− .subject(call),
4402− );
4403− }
4404− for color in bad_hex_colors(value) {
4405− warn(
4406− ctx,
4407− Diagnostic::warning(
4408− code::INVALID_COLOR,
4409− line,
4410− format!(
4411− "invalid hex color '{}': a hex color has 3, 4, 6 or 8 hex digits",
4412− color
4413− ),
4414− )
4415− .subject(color),
4416− );
4417− }
4418− true
4419−}
4420−
4421−/// An unknown prefix: the message, the text it is about, and what to write
4422−/// instead, when something is close enough.
4423−struct PrefixProblem {
4424− message: String,
4425− subject: String,
4426− suggestion: Option<String>,
4427−}
4428−
4429−/// What is wrong with the prefix `rest` starts with, when the known
4430−/// prefixes are already split off it and what is left still starts with
4431−/// one: a word and a `:` (`hovr:`), or a word and a parenthesised argument
4432−/// and a `:` (`nth-chld(2):`). Selector prefixes are CSS's pseudo-classes
4433−/// and pseudo-elements under their CSS names, so an unknown one gets the
4434−/// closest name as a suggestion. Only names with the same first letter are
4435−/// suggested: `odd:` is two edits from `md:`, which it doesn't mean.
4436−fn unknown_prefix(rest: &str) -> Option<PrefixProblem> {
4437− use crate::vocab::{self, Pseudo};
4438− let name_len = rest.find(|c: char| !(c.is_ascii_alphanumeric() || c == '-'))?;
4439− let name = &rest[..name_len];
4440− if name.is_empty() {
4441− return None;
4442− }
4443− if rest[name_len..].starts_with('(') {
4444− // `name(...):`: a pseudo-class with an argument
4445− let close = vocab::closing_paren(rest, name_len)?;
4446− if !rest[close + 1..].starts_with(':') {
4447− return None;
4448− }
4449− let written = &rest[..close + 2];
4450− if matches!(vocab::pseudo(name), Some(Pseudo::Class | Pseudo::Element)) {
4451− let bare = format!("{}:", name);
4452− return Some(PrefixProblem {
4453− message: format!(
4454− "'{}': `{}` takes no argument: write `{}`",
4455− written,
4456− vocab::pseudo_selector(&bare).unwrap_or_default(),
4457− bare
4458− ),
4459− subject: written.to_string(),
4460− suggestion: Some(bare),
4461− });
4462− }
4463− let functional: Vec<&str> = vocab::functional_pseudos()
4464− .into_iter()
4465− .filter(|p| p.chars().next() == name.chars().next())
4466− .collect();
4467− let suggestion = suggest_closest(name, &functional)
4468− .filter(|&closest| closest != name)
4469− .map(|closest| format!("{}(", closest));
4470− let written = format!("{}(", name);
4471− let message = match &suggestion {
4472− Some(closest) => format!("unknown prefix '{}', did you mean '{}'?", written, closest),
4473− None => format!("unknown prefix '{}'", written),
4474− };
4475− return Some(PrefixProblem {
4476− message,
4477− subject: written,
4478− suggestion,
4479− });
4480− }
4481− if !rest[name_len..].starts_with(':') {
4482− return None;
4483− }
4484− let written = &rest[..name_len + 1];
4485− // `has:`: its argument is missing
4486− if vocab::pseudo(name) == Some(Pseudo::Function) {
4487− return Some(PrefixProblem {
4488− message: format!(
4489− "'{}': `:{}()` takes an argument, in parentheses, as in CSS: `{}(...):`",
4490− written, name, name
4491− ),
4492− subject: written.to_string(),
4493− suggestion: None,
4494− });
4495− }
4496− let prefixes = vocab::all_prefixes();
4497− let candidates: Vec<&str> = prefixes
4498− .iter()
4499− .map(String::as_str)
4500− .filter(|p| p.chars().next() == written.chars().next())
4501− .collect();
4502− // The closest name that starts with the same letter (`hvoer:` →
4503− // `hover:`), else the first that starts with the word written and a `-`
4504− // (`first:` → `first-child:`)
4505− let suggestion = suggest_closest(written, &candidates)
4506− .or_else(|| {
4507− let longer = format!("{}-", name);
4508− candidates.iter().copied().find(|p| p.starts_with(&longer))
4509− })
4510− .filter(|&closest| closest != written)
4511− .map(str::to_string);
4512− let message = match &suggestion {
4513− Some(closest) => format!("unknown prefix '{}', did you mean '{}'?", written, closest),
4514− None => format!("unknown prefix '{}'", written),
4515− };
4516− Some(PrefixProblem {
4517− message,
4518− subject: written.to_string(),
4519− suggestion,
4520− })
4521−}
4522−
4523−/// Check an attribute's element prefix (`@td:padding 8`), when it has one:
4524−/// it names a built-in element that has an HTML tag of its own (not a
4525−/// function, and not `@el`, whose `<div>` other elements write too), there
4526−/// is one, not with `children:`, and what it styles is a CSS property, not
4527−/// one of htmlang's words, which compile against each element's layout and
4528−/// its parent's. Returns false, after reporting, when the attribute can't
4529−/// be written.
4530−fn check_element_prefixes(
4531− attr: &Attribute,
4532− prefixes: &[&str],
4533− base: &str,
4534− line: usize,
4535− column: Option<usize>,
4536− ctx: &mut ParseContext,
4537−) -> bool {
4538− use crate::ast::ElementKind;
4539− use crate::vocab;
4540− let elements: Vec<&str> = prefixes
4541− .iter()
4542− .copied()
4543− .filter(|p| vocab::element_prefix(p).is_some())
4544− .collect();
4545− let Some(&prefix) = elements.first() else {
4546− return true;
4547− };
4548− let fail = |ctx: &mut ParseContext,
4549− code: &'static str,
4550− message: String,
4551− subject: &str,
4552− suggestion: Option<String>| {
4553− let diagnostic = Diagnostic::error(code, line, message)
4554− .subject(subject)
4555− .suggest(suggestion);
4556− let diagnostic = at_attribute(diagnostic, column, ctx);
4557− ctx.diagnostics.push(diagnostic);
4558− false
4559− };
4560− let name = vocab::element_prefix(prefix).unwrap_or_default();
4561− if is_function(name, ctx) {
4562− return fail(
4563− ctx,
4564− code::INVALID_PREFIX,
4565− format!(
4566− "'{}': @{} is a function, and `{}` would pick elements out by their HTML tag, \
4567− which a function doesn't have: style what @{} writes in its body, or pass it \
4568− attributes",
4569− attr.key, name, prefix, name
4570− ),
4571− prefix,
4572− None,
4573− );
4574− }
4575− match ElementKind::from_name(name) {
4576− None => {
4577− let own: Vec<&str> = ElementKind::all_names()
4578− .filter(|n| ElementKind::from_name(n).is_some_and(|k| k.own_tag().is_some()))
4579− .collect();
4580− // An HTML name htmlang writes under another (`@a:` is `@link:`)
4581− let (written_otherwise, shared) = match crate::ast::HTML_NAMES_WRITTEN_OTHERWISE
4582− .iter()
4583− .find(|(html, _)| *html == name)
4584− {
4585− Some((_, htmlang)) if own.contains(htmlang) => (Some(*htmlang), false),
4586− Some(_) => (None, true),
4587− None => (None, false),
4588− };
4589− // `@each:`, `@markdown:`: a directive, which is no element
4590− if crate::ast::directive(name).is_some() {
4591− return fail(
4592− ctx,
4593− code::UNKNOWN_PREFIX,
4594− format!(
4595− "unknown element @{} in '{}': @{} is a directive, and an element \
4596− prefix names an element with an HTML tag of its own, such as `@td:`",
4597− name, prefix, name
4598− ),
4599− prefix,
4600− None,
4601− );
4602− }
4603− // `@div:`, `@span:`: several elements write it
4604− if shared {
4605− return fail(
4606− ctx,
4607− code::UNKNOWN_PREFIX,
4608− format!(
4609− "unknown element @{} in '{}': htmlang writes <{}> for several \
4610− elements, so no element prefix picks it out",
4611− name, prefix, name
4612− ),
4613− prefix,
4614− None,
4615− );
4616− }
4617− // A name with the same first letter first (`@tdd:` is `@td:`)
4618− let same_letter: Vec<&str> = own
4619− .iter()
4620− .copied()
4621− .filter(|n| n.chars().next() == name.chars().next())
4622− .collect();
4623− let closest = written_otherwise
4624− .or_else(|| suggest_closest(name, &same_letter))
4625− .or_else(|| suggest_closest(name, &own));
4626− let message = match (closest, written_otherwise) {
4627− (Some(closest), Some(_)) => format!(
4628− "unknown element @{} in '{}', did you mean '@{}:'? (@{} writes <{}>)",
4629− name, prefix, closest, closest, name
4630− ),
4631− (Some(closest), None) => format!(
4632− "unknown element @{} in '{}', did you mean '@{}:'?",
4633− name, prefix, closest
4634− ),
4635− (None, _) => format!("unknown element @{} in '{}'", name, prefix),
4636− };
4637− let suggestion = closest.map(|c| format!("@{}:", c));
4638− fail(ctx, code::UNKNOWN_PREFIX, message, prefix, suggestion)
4639− }
4640− Some(kind) if kind.own_tag().is_none() => {
4641− let reason = match kind.tag() {
4642− None => format!(
4643− "@{} writes no element of its own, so there is nothing for `{}` to style",
4644− name, prefix
4645− ),
4646− Some(_) if kind.is_verbatim() => {
4647− format!("@{} isn't shown, so there is nothing to style", name)
4648− }
4649− Some("span") => format!(
4650− "@{} writes a <span>, as every line of text in a row or column does, so \
4651− `{}` can't pick it out",
4652− name, prefix
4653− ),
4654− Some(tag) => {
4655− let others: Vec<String> = ElementKind::all_names()
4656− .filter(|n| {
4657− *n != name
4658− && ElementKind::from_name(n).and_then(|k| k.tag()) == Some(tag)
4659− })
4660− .map(|n| format!("@{}", n))
4661− .collect();
4662− let others = match others.split_last() {
4663− Some((last, [])) => last.clone(),
4664− Some((last, rest)) => format!("{} and {}", rest.join(", "), last),
4665− None => String::new(),
4666− };
4667− format!(
4668− "@{} writes a <{}>, as {} do, so `{}` can't pick it out",
4669− name, tag, others, prefix
4670− )
4671− }
4672− };
4673− fail(
4674− ctx,
4675− code::INVALID_PREFIX,
4676− format!(
4677− "'{}': {}. Give those elements their styles themselves, or a bundle \
4678− (`@let name [...]`, used as `[$name]`)",
4679− attr.key, reason
4680− ),
4681− prefix,
4682− None,
4683− )
4684− }
4685− Some(_) if elements.len() > 1 => fail(
4686− ctx,
4687− code::INVALID_PREFIX,
4688− format!(
4689− "'{}': a style takes one element prefix, which styles every such element \
4690− inside this one, at any depth",
4691− attr.key
4692− ),
4693− &attr.key,
4694− None,
4695− ),
4696− Some(_) if prefixes.contains(&vocab::CHILDREN) => fail(
4697− ctx,
4698− code::INVALID_PREFIX,
4699− format!(
4700− "'{}': `children:` and `{}` each say which elements the style is for: write \
4701− one of them",
4702− attr.key, prefix
4703− ),
4704− &attr.key,
4705− None,
4706− ),
4707− Some(_) if vocab::is_htmlang_word(base, attr.value.as_deref()) => {
4708− let value = attr.value.as_deref().map(str::trim);
4709− let css = match (base, value) {
4710− ("spacing", _) => " (`gap`)",
4711− ("wrap", _) => " (`flex-wrap wrap`)",
4712− ("grid-cols", _) => " (`grid-template-columns`)",
4713− ("grid-rows", _) => " (`grid-template-rows`)",
4714− ("col-span", _) => " (`grid-column span N`)",
4715− ("row-span", _) => " (`grid-row span N`)",
4716− ("width", Some("fill")) => " (`flex 1` in a row, `width 100%` otherwise)",
4717− ("height", Some("fill")) => " (`flex 1` in a column, `height 100%` otherwise)",
4718− ("width", _) => " (`flex-shrink 0` in a row, `width fit-content` otherwise)",
4719− ("height", _) => " (`flex-shrink 0` in a column, `height fit-content` otherwise)",
4720− ("center-x", _) => " (`margin-inline auto`)",
4721− ("center-y", _) => " (`margin-block auto`)",
4722− _ => "",
4723− };
4724− let word = match value {
4725− Some(v) if matches!(base, "width" | "height") => format!("{} {}", base, v),
4726− _ => base.to_string(),
4727− };
4728− fail(
4729− ctx,
4730− code::INVALID_PREFIX,
4731− format!(
4732− "'{}': `{}` is one of htmlang's layout words, which compile against each \
4733− element's layout and its parent's, and `{}` styles elements whose \
4734− parents it doesn't know: write `{}` on the elements themselves, or the \
4735− CSS you mean{}",
4736− attr.key, word, prefix, word, css
4737− ),
4738− &attr.key,
4739− None,
4740− )
4741− }
4742− Some(_) => true,
4743− }
4744−}
4745−
4746−/// Check an attribute's prefixes: each is known, their selector prefixes
4747−/// read left to right with a pseudo-element (`before:`) last, the argument
4748−/// of `has(...)` or `nth-child(...)` can be written into the CSS, and a word that
4749−/// places an element in its parent (`width fill`, `center-x`, `align-*`)
4750−/// isn't under `children:`, whose styles go on the children. Media,
4751−/// container and width prefixes go anywhere. Returns false, after
4752−/// reporting, when the attribute can't be written.
4753−fn check_prefixes(
4754− attr: &Attribute,
4755− line: usize,
4756− column: Option<usize>,
4757− ctx: &mut ParseContext,
4758−) -> bool {
4759− use crate::vocab;
4760− let (prefixes, base) = vocab::split_prefixes(&attr.key);
4761− let fail =
4762− |ctx: &mut ParseContext, message: String, subject: &str, suggestion: Option<String>| {
4763− let diagnostic = Diagnostic::error(code::INVALID_PREFIX, line, message)
4764− .subject(subject)
4765− .suggest(suggestion);
4766− let diagnostic = at_attribute(diagnostic, column, ctx);
4767− ctx.diagnostics.push(diagnostic);
4768− false
4769− };
4770−
4771− if let Some(problem) = unknown_prefix(base) {
4772− let diagnostic = Diagnostic::error(code::UNKNOWN_PREFIX, line, problem.message)
4773− .subject(problem.subject)
4774− .suggest(problem.suggestion);
4775− let diagnostic = at_attribute(diagnostic, column, ctx);
4776− ctx.diagnostics.push(diagnostic);
4777− return false;
4778− }
4779− if !check_element_prefixes(attr, &prefixes, base, line, column, ctx) {
4780− return false;
4781− }
4782− // The argument of `has(...)` or `nth-child(...)` goes into the CSS as
4783− // written
4784− for prefix in &prefixes {
4785− if let Some(reason) = css_breakout(prefix.trim_end_matches(':')) {
4786− return fail(
4787− ctx,
4788− format!(
4789− "the prefix '{}' has {}: it can't be written into the page's CSS",
4790− prefix, reason
4791− ),
4792− prefix,
4793− None,
4794− );
4795− }
4796− }
4797− // `nth-child():` or `has( ):`: CSS has no pseudo-class with an empty
4798− // argument
4799− let empty_argument = |prefix: &str| {
4800− prefix
4801− .strip_suffix("):")
4802− .and_then(|p| p.split_once('('))
4803− .is_some_and(|(_, argument)| argument.trim().is_empty())
4804− };
4805− if let Some(empty) = prefixes.iter().find(|p| empty_argument(p)) {
4806− return fail(
4807− ctx,
4808− format!(
4809− "'{}': `:{}()` takes an argument between its parentheses, as in CSS",
4810− attr.key,
4811− vocab::pseudo_name(empty)
4812− ),
4813− empty,
4814− None,
4815− );
4816− }
4817− // A pseudo-element is the last selector prefix: CSS has no
4818− // `::before:hover`
4819− let selectors: Vec<&str> = prefixes
4820− .iter()
4821− .copied()
4822− .filter(|p| vocab::at_rule_rank(p).is_none())
4823− .collect();
4824− // Only one: an element has one `::before`, which has no `::after`
4825− let elements: Vec<&str> = selectors
4826− .iter()
4827− .copied()
4828− .filter(|p| vocab::is_pseudo_element(p))
4829− .collect();
4830− if elements.len() > 1 {
4831− return fail(
4832− ctx,
4833− format!(
4834− "'{}': `{}` and `{}` each select a pseudo-element, and a style applies to one \
4835− of them",
4836− attr.key, elements[0], elements[1]
4837− ),
4838− &attr.key,
4839− None,
4840− );
4841− }
4842− if let Some(at) = selectors.iter().position(|p| vocab::is_pseudo_element(p))
4843− && at + 1 < selectors.len()
4844− {
4845− let element = selectors[at];
4846− // The same prefixes, with the pseudo-element moved after the other
4847− // selector prefixes
4848− let mut order: Vec<&str> = prefixes.iter().copied().filter(|p| *p != element).collect();
4849− let last_selector = order
4850− .iter()
4851− .rposition(|p| vocab::at_rule_rank(p).is_none())
4852− .map_or(order.len(), |i| i + 1);
4853− order.insert(last_selector, element);
4854− let fixed = format!("{}{}", order.concat(), base);
4855− return fail(
4856− ctx,
4857− format!(
4858− "'{}': `{}` selects a pseudo-element, which comes after the other selector \
4859− prefixes, as in CSS: write `{}`",
4860− attr.key, element, fixed
4861− ),
4862− &attr.key,
4863− Some(fixed),
4864− );
4865− }
4866− // Under `children:` the styles go on the children, whose parent is this
4867− // element: a word that places an element in its parent can't say where
4868− if prefixes.contains(&"children:") && vocab::places_in_parent(base, attr.value.as_deref()) {
4869− // The CSS of `fill` and `shrink` depends on the direction: along
4870− // it, they are flex properties
4871− let (word, css) = match (base, attr.value.as_deref().map(str::trim)) {
4872− ("width", Some("fill")) => (
4873− "width fill",
4874− " (`children:flex 1` in a row, `children:width 100%` otherwise)",
4875− ),
4876− ("height", Some("fill")) => (
4877− "height fill",
4878− " (`children:flex 1` in a column, `children:height 100%` otherwise)",
4879− ),
4880− ("width", Some(_)) => (
4881− "width shrink",
4882− " (`children:flex-shrink 0` in a row, `children:width fit-content` otherwise)",
4883− ),
4884− ("height", Some(_)) => (
4885− "height shrink",
4886− " (`children:flex-shrink 0` in a column, `children:height fit-content` \
4887− otherwise)",
4888− ),
4889− _ => (base, ""),
4890− };
4891− return fail(
4892− ctx,
4893− format!(
4894− "'{}{}': `{}` places an element in its parent, and under `children:` that \
4895− parent is this element: write `{}` on the children themselves, or the CSS \
4896− you mean{}",
4897− attr.key,
4898− attr.value
4899− .as_deref()
4900− .map_or(String::new(), |v| format!(" {}", v.trim())),
4901− word,
4902− word,
4903− css
4904− ),
4905− &attr.key,
4906− None,
4907− );
4908− }
4909− true
4910−}
4911−
4912−/// Check an attribute written as a style or a flag (not `key=value`): its
4913−/// prefix, its name, and, for a style, its value. A name htmlang doesn't
4914−/// know but CSS could have (`corner-shape`) is passed to the CSS as written,
4915−/// with a warning; custom properties (`--brand`) and vendor-prefixed ones
4916−/// (`-webkit-...`) without one. Anything that can't be written into the
4917−/// page is an error; returns false then, and the attribute is left out.
4918−fn check_attribute(
4919− attr: &Attribute,
4920− line: usize,
4921− column: Option<usize>,
4922− before: Option<&Attribute>,
4923− ctx: &mut ParseContext,
4924−) -> bool {
4925− use crate::vocab;
4926− let (prefixes, base) = vocab::split_prefixes(&attr.key);
4927− let fail = |ctx: &mut ParseContext, code: &'static str, message: String, subject: &str| {
4928− let diagnostic = Diagnostic::error(code, line, message).subject(subject);
4929− let diagnostic = at_attribute(diagnostic, column, ctx);
4930− ctx.diagnostics.push(diagnostic);
4931− false
4932− };
4933−
4934− if !check_prefixes(attr, line, column, ctx) {
4935− return false;
4936− }
4937− let prefixed = !prefixes.is_empty();
4938− // `md:id=x`: `=` makes an HTML attribute, which has no states
4939− if prefixed && let Some((name, _)) = base.split_once('=') {
4940− return fail(
4941− ctx,
4942− code::INVALID_PREFIX,
4943− format!(
4944− "'{}': a prefix applies to a style, and `{}=` is an HTML attribute",
4945− attr.key, name
4946− ),
4947− &attr.key,
4948− );
4949− }
4950− let Some(value) = &attr.value else {
4951− // `inline` puts a file into the page as it compiles, which no
4952− // state or media condition can undo
4953− if base == "inline" && prefixed {
4954− return fail(
4955− ctx,
4956− code::INVALID_PREFIX,
4957− format!(
4958− "'{}': `inline` puts the image's file into the page, which can't depend \
4959− on a prefix",
4960− attr.key
4961− ),
4962− &attr.key,
4963− );
4964− }
4965− if vocab::HTMLANG_FLAGS.contains(&base) {
4966− return true;
4967− }
4968− if vocab::is_html_flag(base) {
4969− if !prefixed {
4970− return true;
4971− }
4972− return fail(
4973− ctx,
4974− code::INVALID_PREFIX,
4975− format!(
4976− "'{}': a prefix applies to a style, and '{}' is an HTML attribute",
4977− attr.key, base
4978− ),
4979− &attr.key,
4980− );
4981− }
4982− if vocab::is_style_attribute(base)
4983− || vocab::is_custom_property(base)
4984− || vocab::is_vendor_property(base)
4985− {
4986− return fail(
4987− ctx,
4988− code::MISSING_VALUE,
4989− format!("'{}' needs a value: `{} VALUE`", attr.key, attr.key),
4990− &attr.key,
4991− );
4992− }
4993− if vocab::is_html_attribute(base) && !prefixed {
4994− return fail(
4995− ctx,
4996− code::HTML_ATTRIBUTE_FORM,
4997− format!(
4998− "'{}' is an HTML attribute that isn't a flag: write `{}=VALUE`",
4999− base, base
5000− ),
5001− base,
5002− );
5003− }
5004− return unknown_attribute(attr, base, line, column, before, true, ctx);
5005− };
5006−
5007− if vocab::HTMLANG_FLAGS.contains(&base) {
5008− return fail(
5009− ctx,
5010− code::INVALID_VALUE,
5011− format!(
5012− "'{}' is a flag and takes no value: write `{}` alone",
5013− base, attr.key
5014− ),
5015− &attr.key,
5016− );
5017− }
5018− if vocab::is_style_attribute(base)
5019− || vocab::is_custom_property(base)
5020− || vocab::is_vendor_property(base)
5021− {
5022− return check_css_value(attr, base, line, column, ctx);
5023− }
5024− if vocab::is_html_attribute(base) && !prefixed {
5025− let diagnostic = Diagnostic::error(
5026− code::HTML_ATTRIBUTE_FORM,
5027− line,
5028− format!(
5029− "'{}' is an HTML attribute: write `{}={}`",
5030− attr.key, attr.key, value
5031− ),
5032− )
5033− .subject(attr.key.as_str());
5034− let diagnostic = at_attribute(diagnostic, column, ctx);
5035− ctx.diagnostics.push(diagnostic);
5036− return false;
5037− }
5038− let passes = vocab::is_property_name(base);
5039− unknown_attribute(attr, base, line, column, before, !passes, ctx)
5040− && check_css_value(attr, base, line, column, ctx)
5041−}
5042−
5043−/// Whether an attribute of a bundle could pass a parameter to a function
5044−/// it is spliced into (`@let t [title Hello]`): a name without a prefix
5045−/// that isn't a style or a flag. Such a name is checked where the bundle is
5046−/// used.
5047−fn could_be_parameter(attr: &Attribute) -> bool {
5048− use crate::vocab;
5049− let key = attr.key.as_str();
5050− let flag =
5051− attr.value.is_none() && (vocab::HTMLANG_FLAGS.contains(&key) || vocab::is_html_flag(key));
5052− !attr.html
5053− && !flag
5054− && !vocab::is_style_attribute(key)
5055− && key.starts_with(|c: char| c.is_alphabetic())
5056− && key
5057− .chars()
5058− .all(|c| c.is_alphanumeric() || matches!(c, '-' | '_'))
5059−}
5060−
5061−/// At a call, a name close to one of the function's parameters is a
5062−/// misspelled parameter, not an attribute for its root: report it, and
5063−/// return true (it is left out).
5064−fn misspelled_parameter(
5065− attr: &Attribute,
5066− text_keys: &[String],
5067− line: usize,
5068− column: Option<usize>,
5069− ctx: &mut ParseContext,
5070−) -> bool {
5071− if text_keys.is_empty() || !could_be_parameter(attr) {
5072− return false;
5073− }
5074− let params: Vec<&str> = text_keys.iter().map(String::as_str).collect();
5075− let Some(closest) = suggest_closest(&attr.key, ¶ms) else {
5076− return false;
5077− };
5078− let what = if ctx.in_page {
5079− "@page word"
5080− } else {
5081− "parameter"
5082− };
5083− let diagnostic = Diagnostic::error(
5084− code::UNKNOWN_ATTRIBUTE,
5085− line,
5086− format!(
5087− "unknown {} '{}', did you mean '{}'?",
5088− what, attr.key, closest
5089− ),
5090− )
5091− .subject(attr.key.as_str())
5092− .suggest(Some(closest));
5093− let diagnostic = at_attribute(diagnostic, column, ctx);
5094− ctx.diagnostics.push(diagnostic);
5095− true
5096−}
5097−
5098−/// An attribute name htmlang doesn't know. A style whose name CSS could
5099−/// have goes to the CSS as written, with a warning; anything else (a flag,
5100−/// a name that isn't a word) is an error. Returns whether it is kept.
5101−fn unknown_attribute(
5102− attr: &Attribute,
5103− base: &str,
5104− line: usize,
5105− column: Option<usize>,
5106− before: Option<&Attribute>,
5107− error: bool,
5108− ctx: &mut ParseContext,
5109−) -> bool {
5110− // `@td padding 8`: an element prefix without its colon
5111− if let Some(name) = base.strip_prefix('@')
5112− && crate::ast::ElementKind::from_name(name).is_some()
5113− {
5114− let example = match attr.value.as_deref() {
5115− Some(value) => format!("{}:{}", attr.key, value.trim()),
5116− None => format!("{}:padding 8", attr.key),
5117− };
5118− let diagnostic = Diagnostic::error(
5119− code::UNKNOWN_ATTRIBUTE,
5120− line,
5121− format!(
5122− "unknown attribute '{}': an element prefix ends in a colon, as in `{}`",
5123− attr.key, example
5124− ),
5125− )
5126− .subject(base);
5127− let diagnostic = at_attribute(diagnostic, column, ctx);
5128− ctx.diagnostics.push(diagnostic);
5129− return false;
5130− }
5131− // `[card]` where `card` is a bundle: it is used as `$card`
5132− if attr.value.is_none() && ctx.env.bundle(base).is_some() && base == attr.key {
5133− ctx.used_defines.insert(base.to_string());
5134− let diagnostic = Diagnostic::error(
5135− code::UNKNOWN_ATTRIBUTE,
5136− line,
5137− format!(
5138− "unknown attribute '{}': '{}' is an attribute bundle, used as `${}`",
5139− base, base, base
5140− ),
5141− )
5142− .subject(base)
5143− .suggest(Some(format!("${}", base)));
5144− let diagnostic = at_attribute(diagnostic, column, ctx);
5145− ctx.diagnostics.push(diagnostic);
5146− return false;
5147− }
5148− // `hover:title x`: an HTML attribute's name is not a suggestion for
5149− // itself
5150− let suggestion =
5151− suggest_closest(base, &crate::vocab::all_attributes()).filter(|&closest| closest != base);
5152− // `hx-trigger=load, every 2s`: right after a `key=value`, a name that
5153− // isn't close to one htmlang knows is the rest of that value, which
5154− // the comma ended. It is left out.
5155− let cut = before.filter(|b| b.html && b.value.is_some());
5156− let rest = match &attr.value {
5157− Some(value) => format!("{} {}", attr.key, value),
5158− None => attr.key.clone(),
5159− };
5160− let joined = cut.map(|cut| {
5161− let value = cut.value.as_deref().unwrap_or("");
5162− (
5163− format!("{}={}", cut.key, value),
5164− format!("{}={}\\, {}", cut.key, value, rest),
5165− )
5166− });
5167− if let (Some((cut, joined)), None) = (&joined, suggestion) {
5168− let diagnostic = Diagnostic::error(
5169− code::SPLIT_VALUE,
5170− line,
5171− format!(
5172− "unknown attribute '{}' after `{}`: if '{}' is the rest of its value, the comma \
5173− ended it. To keep a comma in a value, write `\\,`: `{}`",
5174− base, cut, rest, joined
5175− ),
5176− )
5177− .subject(base);
5178− let diagnostic = at_attribute(diagnostic, column, ctx);
5179− ctx.diagnostics.push(diagnostic);
5180− return false;
5181− }
5182− let mut message = match (&suggestion, error) {
5183− (Some(closest), true) => {
5184− format!(
5185− "unknown attribute '{}', did you mean '{}'?",
5186− attr.key, closest
5187− )
5188− }
5189− (None, true) => format!("unknown attribute '{}'", attr.key),
5190− (Some(closest), false) => format!(
5191− "unknown CSS property '{}', did you mean '{}'? It is written to the CSS as it is",
5192− base, closest
5193− ),
5194− (None, false) => format!(
5195− "unknown CSS property '{}': it is written to the CSS as it is",
5196− base
5197− ),
5198− };
5199− // `box-shadow 0 1px red, 0 2px blue` or `font-family Inter,
5200− // sans-serif`: the comma ended the attribute, and the rest of the
5201− // value became one
5202− let rest_of_a_value = !base.starts_with(|c: char| c.is_ascii_alphabetic() || c == '-')
5203− || (suggestion.is_none() && attr.value.is_none() && before.is_some());
5204− if joined.is_some() || (rest_of_a_value && error) {
5205− if !message.ends_with('?') {
5206− message.push('.');
5207− }
5208− match &joined {
5209− Some((cut, joined)) => message.push_str(&format!(
5210− " If it is the rest of `{}`, the comma ended it: write `{}`",
5211− cut, joined
5212− )),
5213− None => message
5214− .push_str(" A comma separates attributes: to keep one in a value, write `\\,`"),
5215− }
5216− }
5217− let severity = if error {
5218− Severity::Error
5219− } else {
5220− Severity::Warning
5221− };
5222− let diagnostic = Diagnostic::new(code::UNKNOWN_ATTRIBUTE, severity, line, message)
5223− .subject(base)
5224− .suggest(suggestion);
5225− let diagnostic = at_attribute(diagnostic, column, ctx);
5226− ctx.diagnostics.push(diagnostic);
5227− !error
5228−}
5229−
5230−/// Evaluate the attributes of a list: bundles are spliced in, `if()`
5231−/// chooses, and variables fill values. A variable fills only the value it
5232−/// is written in: attributes come from bundles, never from text. With
5233−/// `validate`, unknown names and invalid values are reported. `text_keys`
5234−/// are a called function's parameters: their values are text rather than
5235−/// CSS, and they aren't checked as attributes.
5236−fn parse_attr_list(
5237− tokens: &[syntax::Attr],
5238− line_num: usize,
5239− ctx: &mut ParseContext,
5240− validate: bool,
5241− text_keys: &[String],
5242−) -> Vec<Attribute> {
5243− parse_attrs(tokens, line_num, ctx, validate, text_keys)
5244− .into_iter()
5245− .map(|(attr, _)| attr)
5246− .collect()
5247−}
5248−
5249−/// [`parse_attr_list`], with the value of each attribute whose key is one
5250−/// of `text_keys` (a call's parameters) as a value with its type (see
5251−/// [`ParseContext::slot_value`]), so a parameter can get a list or a
5252−/// record.
5253−fn parse_attrs(
5254− tokens: &[syntax::Attr],
5255− line_num: usize,
5256− ctx: &mut ParseContext,
5257− validate: bool,
5258− text_keys: &[String],
5259−) -> Vec<(Attribute, Option<Value>)> {
5260− let mut read = ReadAttrs::default();
5261− read_attrs(tokens, "", line_num, ctx, validate, text_keys, &mut read);
5262− read.attrs
5263−}
5264−
5265−/// The attributes of a list read so far, and the keys written (for the
5266−/// duplicate check).
5267−#[derive(Default)]
5268−struct ReadAttrs {
5269− attrs: Vec<(Attribute, Option<Value>)>,
5270− seen_keys: Vec<(String, bool)>,
5271−}
5272−
5273−/// [`parse_attrs`] for the attributes of `tokens`, each under the prefixes
5274−/// `prefix` (`md:` for those of `md:[...]`), which distribute over a
5275−/// group, a bundle and the branch an `if()` takes. Only styles take a
5276−/// prefix, so an HTML attribute there is an error.
5277−fn read_attrs(
5278− tokens: &[syntax::Attr],
5279− prefix: &str,
5280− line_num: usize,
5281− ctx: &mut ParseContext,
5282− validate: bool,
5283− text_keys: &[String],
5284− out: &mut ReadAttrs,
5285−) {
5286− let mut chosen = Vec::new();
5287− choose_attrs(
5288− tokens,
5289− prefix,
5290− line_num,
5291− ctx,
5292− validate,
5293− text_keys,
5294− &mut chosen,
5295− );
5296−
5297− for token in &chosen {
5298− let line = if token.span.line == 0 {
5299− line_num
5300− } else {
5301− token.span.line
5302− };
5303− let (key, value, html) = (token.key.clone(), token.value.clone(), token.html);
5304− let column = |at: usize| Some(token.span.column + at);
5305−
5306− // `md:[...]`, `md:$card`, `md:if(...)`: the prefixes apply to each
5307− // attribute there, and a prefix a parameter can't have
5308− if let Some(prefixed) = &token.prefixed {
5309− if let Some(inner) = group_prefix(token, prefixed, prefix, line, ctx) {
5310− read_attrs(
5311− prefixed.target.attrs(),
5312− &inner,
5313− line_num,
5314− ctx,
5315− validate,
5316− text_keys,
5317− out,
5318− );
5319− }
5320− continue;
5321− }
5322−
5323− // `$name` (or `${name}`) alone: an attribute bundle, spliced in
5324− let bundle = key.strip_prefix('$').filter(|_| value.is_none() && !html);
5325− let bundle = bundle.and_then(|after| match interp::reference(after, &ctx.env)? {
5326− (interp::Reference::Var(name), len) if len == after.len() => Some(name),
5327− _ => None,
5328− });
5329− if let Some(name) = bundle {
5330− if let Some(define_attrs) = ctx.env.bundle(&name).cloned() {
5331− ctx.used_defines.insert(name.clone());
5332− for attr in define_attrs.iter() {
5333− if !prefix.is_empty() {
5334− let prefixed = Attribute {
5335− key: format!("{}{}", prefix, attr.key),
5336− ..attr.clone()
5337− };
5338− if prefixed_parameter(&prefixed, text_keys, line, column(0), validate, ctx)
5339− {
5340− continue;
5341− }
5342− if let Some(attr) =
5343− prefixed_member(attr, prefix, &name, line, column(0), validate, ctx)
5344− {
5345− out.attrs.push((attr, None));
5346− }
5347− continue;
5348− }
5349− let attrs = &out.attrs;
5350− // Checked here, where it is either a parameter or not
5351− let checked_here = validate
5352− && !ctx.in_bundle
5353− && could_be_parameter(attr)
5354− && !text_keys.contains(&attr.key);
5355− if checked_here
5356− && (misspelled_parameter(attr, text_keys, line, column(0), ctx)
5357− || !check_attribute(
5358− attr,
5359− line,
5360− column(0),
5361− attrs.last().map(|(a, _)| a),
5362− ctx,
5363− ))
5364− {
5365− continue;
5366− }
5367− out.attrs.push((attr.clone(), None));
5368− }
5369− } else {
5370− not_a_bundle(&name, line, column(0), ctx);
5371− }
5372− continue;
5373− }
5374− // A name never comes from a variable
5375− if key.contains('$') {
5376− track_var_refs(&key, &mut ctx.used_variables);
5377− ctx.diagnostics.push(
5378− Diagnostic::error(
5379− code::ATTRIBUTE_FROM_VARIABLE,
5380− line,
5381− format!(
5382− "'{}': an attribute's name can't come from a variable. A variable \
5383− fills a value (`padding $size`), and whole attributes come from a \
5384− bundle (`@let name [padding 8]`, used as `[$name]`)",
5385− key
5386− ),
5387− )
5388− .subject(key.as_str()),
5389− );
5390− continue;
5391− }
5392−
5393− // Only a style has states: `md:[id=x]`, `md:id=x`
5394− if html && (!prefix.is_empty() || !crate::vocab::split_prefixes(&key).0.is_empty()) {
5395− let written = format!("{}{}", prefix, key);
5396− let (name, _) = crate::vocab::split_prefixes(&written);
5397− let diagnostic = Diagnostic::error(
5398− code::INVALID_PREFIX,
5399− line,
5400− format!(
5401− "'{}=': a prefix applies to a style, and `{}=` is an HTML attribute, \
5402− which has no states",
5403− written,
5404− &written[name.concat().len()..]
5405− ),
5406− )
5407− .subject(token.key.as_str());
5408− let diagnostic = at_attribute(diagnostic, column(0), ctx);
5409− ctx.diagnostics.push(diagnostic);
5410− continue;
5411− }
5412− let key = if prefix.is_empty() {
5413− key
5414− } else {
5415− format!("{}{}", prefix, key)
5416− };
5417−
5418− // A value's variables are filled in. A style's value is CSS, where
5419− // quoted text keeps its quotes; an HTML attribute's (and a
5420− // parameter's) is text, where it loses them.
5421− let sink = if html || text_keys.contains(&key) {
5422− Sink::Text
5423− } else {
5424− Sink::Css
5425− };
5426− let mut filled = true;
5427− let mut quoted = None;
5428− let mut typed = None;
5429− let value = match value {
5430− None => None,
5431− // A parameter's value keeps its type
5432− Some(value) if !html && text_keys.contains(&key) => {
5433− let at = column(token.raw.len() - value.len());
5434− let (value, ok) = ctx.slot_value(&value, line, at);
5435− filled = ok;
5436− if let Value::Quoted(q) = &value {
5437− quoted = Some(q.clone());
5438− }
5439− let text = value.to_string();
5440− typed = Some(value);
5441− Some(text)
5442− }
5443− Some(value) => {
5444− let at = column(token.raw.len() - value.len());
5445− let (text, is_quoted, ok) = ctx.fill_value(&value, line, at, sink);
5446− filled = ok;
5447− quoted = is_quoted;
5448− Some(text)
5449− }
5450− };
5451− let attr = Attribute {
5452− key,
5453− value,
5454− html,
5455− quoted,
5456− };
5457− // A value that couldn't be filled in is already reported, and a
5458− // parameter's value is text for the function
5459− let validate = validate && filled && !text_keys.contains(&attr.key);
5460−
5461− // A duplicate is reported (compare the full key, so `border` and
5462− // `hover:border` differ, and the form, so `width=800` and
5463− // `width 200` do too), and the later one wins
5464− if validate {
5465− let seen = (normal_key(&attr.key), attr.html);
5466− if out.seen_keys.contains(&seen) {
5467− let written = if attr.html { "=" } else { "" };
5468− let message = format!(
5469− "duplicate attribute '{}{}': the later one wins",
5470− attr.key, written
5471− );
5472− let diagnostic = Diagnostic::warning(code::DUPLICATE_ATTRIBUTE, line, message)
5473− .subject(attr.key.as_str());
5474− let diagnostic = at_attribute(diagnostic, column(0), ctx);
5475− ctx.diagnostics.push(diagnostic);
5476− } else {
5477− out.seen_keys.push(seen);
5478− }
5479− }
5480−
5481− if validate && misspelled_parameter(&attr, text_keys, line, column(0), ctx) {
5482− continue;
5483− }
5484− if prefixed_parameter(&attr, text_keys, line, column(0), validate, ctx) {
5485− continue;
5486− }
5487− if validate && attr.html && attr.key == "class" {
5488− reserved_class(&attr, line, column(0), ctx);
5489− }
5490− // `padding=4`: a style written as an HTML attribute, which the
5491− // browser ignores (`width=` and `height=` are real on some
5492− // elements, see `validate_tree`)
5493− if validate
5494− && attr.html
5495− && crate::vocab::is_style_attribute(&attr.key)
5496− && !crate::vocab::HTML_ATTRIBUTES.contains(&attr.key.as_str())
5497− {
5498− let value = token.value.as_deref().unwrap_or("").trim();
5499− let diagnostic = Diagnostic::warning(
5500− code::HTML_ATTRIBUTE_FORM,
5501− line,
5502− format!(
5503− "'{0}={1}' is an HTML attribute, but {0} is a style: write `{0} {1}`",
5504− attr.key, value
5505− ),
5506− )
5507− .subject(token.raw.as_str())
5508− .suggest(Some(format!("{} {}", attr.key, value)));
5509− let diagnostic = at_attribute(diagnostic, column(0), ctx);
5510− ctx.diagnostics.push(diagnostic);
5511− }
5512−
5513− // A style or a flag: its name is checked, and what can't be
5514− // written into the page is an error and left out
5515− let checked = validate && !attr.html && !(ctx.in_bundle && could_be_parameter(&attr));
5516− let before = out.attrs.last().map(|(a, _)| a);
5517− if checked && !check_attribute(&attr, line, column(0), before, ctx) {
5518− continue;
5519− }
5520−
5521− out.attrs.push((attr, typed));
5522− }
5523−}
5524−
5525−/// At a call, a parameter under prefixes (`md:title x`, `md:[title x]`):
5526−/// a parameter has one value, with no states, so it is reported (with
5527−/// `validate`) and left out; returns true then. A parameter named like a
5528−/// style (`color`) is a style under a prefix, for the root element.
5529−fn prefixed_parameter(
5530− attr: &Attribute,
5531− text_keys: &[String],
5532− line: usize,
5533− column: Option<usize>,
5534− validate: bool,
5535− ctx: &mut ParseContext,
5536−) -> bool {
5537− let (prefixes, name) = crate::vocab::split_prefixes(&attr.key);
5538− if attr.html
5539− || prefixes.is_empty()
5540− || !text_keys.iter().any(|k| k == name)
5541− || crate::vocab::is_style_attribute(name)
5542− {
5543− return false;
5544− }
5545− if validate {
5546− let what = if ctx.in_page {
5547− "@page's own word"
5548− } else {
5549− "a parameter"
5550− };
5551− let diagnostic = Diagnostic::error(
5552− code::INVALID_PREFIX,
5553− line,
5554− format!(
5555− "'{}': `{}` is {}, which has one value, and a prefix applies to a style, \
5556− which has states",
5557− attr.key, name, what
5558− ),
5559− )
5560− .subject(attr.key.as_str());
5561− let diagnostic = at_attribute(diagnostic, column, ctx);
5562− ctx.diagnostics.push(diagnostic);
5563− }
5564− true
5565−}
5566−
5567−/// The prefixes of a prefixed group, bundle or `if()` inside `outer` (the
5568−/// prefixes of the groups it is in), when they are all known; else the
5569−/// unknown one is reported. Text after a group's `]` is an error too.
5570−fn group_prefix(
5571− token: &syntax::Attr,
5572− prefixed: &syntax::Prefixed,
5573− outer: &str,
5574− line: usize,
5575− ctx: &mut ParseContext,
5576−) -> Option<String> {
5577− let at = |ctx: &ParseContext, diagnostic: Diagnostic, span: syntax::Span| match &ctx
5578− .current_source
5579− {
5580− (current, Some(text)) if span.line != 0 && *current == span.line => {
5581− diagnostic.column(span.column).source(text.clone())
5582− }
5583− _ => diagnostic,
5584− };
5585− if let syntax::Branch::Group {
5586− trailing: Some(trailing),
5587− ..
5588− } = &prefixed.target
5589− {
5590− let diagnostic = Diagnostic::error(
5591− code::UNEXPECTED_ARGUMENT,
5592− line,
5593− format!(
5594− "'{}' after the `]` of `{}[...]`: the prefixes apply to the attributes in the \
5595− group, so it goes inside it",
5596− trailing.raw, prefixed.prefix
5597− ),
5598− )
5599− .subject(trailing.raw.as_str());
5600− let diagnostic = at(ctx, diagnostic, trailing.span);
5601− ctx.push_once(diagnostic);
5602− }
5603− let (known, rest) = crate::vocab::split_prefixes(&prefixed.prefix);
5604− if !rest.is_empty() {
5605− let problem = unknown_prefix(rest).unwrap_or_else(|| {
5606− let written = rest.split_inclusive(':').next().unwrap_or(rest);
5607− PrefixProblem {
5608− message: format!("unknown prefix '{}'", written),
5609− subject: written.to_string(),
5610− suggestion: None,
5611− }
5612− });
5613− let diagnostic = Diagnostic::error(code::UNKNOWN_PREFIX, line, problem.message)
5614− .subject(problem.subject)
5615− .suggest(problem.suggestion);
5616− let diagnostic = at(ctx, diagnostic, token.span);
5617− ctx.push_once(diagnostic);
5618− return None;
5619− }
5620− Some(format!("{}{}", outer, known.concat()))
5621−}
5622−
5623−/// An attribute of the bundle `bundle`, spliced in under `prefix`
5624−/// (`md:$card`): the same attribute with the prefixes in front, when it can
5625−/// take them. An HTML attribute can't; a style's prefixes are checked, as
5626−/// is a flag or a name that isn't a style (a bundle's parameter), which
5627−/// under a prefix are attributes like any other.
5628−fn prefixed_member(
5629− attr: &Attribute,
5630− prefix: &str,
5631− bundle: &str,
5632− line: usize,
5633− column: Option<usize>,
5634− validate: bool,
5635− ctx: &mut ParseContext,
5636−) -> Option<Attribute> {
5637− let key = format!("{}{}", prefix, attr.key);
5638− if attr.html {
5639− if validate {
5640− let diagnostic = Diagnostic::error(
5641− code::INVALID_PREFIX,
5642− line,
5643− format!(
5644− "'{}${}': the bundle has `{}=`, an HTML attribute, and a prefix applies to \
5645− styles, which have states",
5646− prefix, bundle, attr.key
5647− ),
5648− )
5649− .subject(format!("{}${}", prefix, bundle));
5650− let diagnostic = at_attribute(diagnostic, column, ctx);
5651− ctx.diagnostics.push(diagnostic);
5652− }
5653− return None;
5654− }
5655− let prefixed = Attribute {
5656− key,
5657− ..attr.clone()
5658− };
5659− if validate {
5660− let fine = if attr.value.is_none() || could_be_parameter(attr) {
5661− check_attribute(&prefixed, line, column, None, ctx)
5662− } else {
5663− check_prefixes(&prefixed, line, column, ctx)
5664− };
5665− if !fine {
5666− return None;
5667− }
5668− }
5669− Some(prefixed)
5670−}
5671−
5672−/// `class=hl-x`: the `hl-` prefix is htmlang's, for its generated classes,
5673−/// whose rules would then apply to the element too. It goes into the page
5674−/// as written, so this is a warning.
5675−fn reserved_class(attr: &Attribute, line: usize, column: Option<usize>, ctx: &mut ParseContext) {
5676− let classes = attr.value.as_deref().unwrap_or_default();
5677− for class in classes.split_whitespace() {
5678− if class.starts_with(crate::codegen::CLASS_PREFIX) {
5679− let diagnostic = Diagnostic::warning(
5680− code::INVALID_VALUE,
5681− line,
5682− format!(
5683− "class '{}' starts with `{}`, which htmlang keeps for the classes it \
5684− generates, so their styles could apply to this element: give it \
5685− another name",
5686− class,
5687− crate::codegen::CLASS_PREFIX
5688− ),
5689− )
5690− .subject(class);
5691− let diagnostic = at_attribute(diagnostic, column, ctx);
5692− ctx.diagnostics.push(diagnostic);
5693− }
5694− }
5695−}
5696−
5697−/// A style's key as the CSS reads it, for finding duplicates: its at-rule
5698−/// prefixes in one order (`dark:md:` is `md:dark:`), then its selector
5699−/// prefixes as written, whose order is the selector's.
5700−fn normal_key(key: &str) -> String {
5701− let (prefixes, name) = crate::vocab::split_prefixes(key);
5702− let mut at: Vec<(usize, &str)> = prefixes
5703− .iter()
5704− .filter_map(|p| crate::vocab::at_rule_rank(p).map(|rank| (rank, *p)))
5705− .collect();
5706− at.sort_unstable();
5707− at.dedup();
5708− let mut normal: String = at.iter().map(|(_, p)| *p).collect();
5709− for prefix in prefixes
5710− .iter()
5711− .filter(|p| crate::vocab::at_rule_rank(p).is_none())
5712− {
5713− normal.push_str(prefix);
5714− }
5715− normal.push_str(name);
5716− normal
5717−}
5718−
5719−/// `[$name]` where `$name` isn't an attribute bundle.
5720−fn not_a_bundle(name: &str, line: usize, column: Option<usize>, ctx: &mut ParseContext) {
5721− track_var_refs(&format!("${}", name), &mut ctx.used_variables);
5722− let is_value = interp::name_len(name) > 0 && interp::resolve(name, &ctx.env).is_some();
5723− let diagnostic = if is_value {
5724− Diagnostic::error(
5725− code::ATTRIBUTE_FROM_VARIABLE,
5726− line,
5727− format!(
5728− "'${}' is a value, not an attribute: attributes come from a bundle \
5729− (`@let name [padding 8]`, used as `[$name]`), and a value fills an \
5730− attribute's value (`padding ${}`)",
5731− name, name
5732− ),
5733− )
5734− .subject(name)
5735− } else if ctx.env.function(name).is_some() {
5736− ctx.used_functions.insert(name.to_string());
5737− Diagnostic::error(
5738− code::UNDEFINED_VARIABLE,
5739− line,
5740− format!(
5741− "'${}' is a function, not an attribute bundle: it is called as an element, \
5742− `@{}`",
5743− name, name
5744− ),
5745− )
5746− .subject(name)
5747− } else {
5748− let mut bundles = ctx.env.bundle_names();
5749− bundles.sort_unstable();
5750− let suggestion = suggest_closest(name, &bundles);
5751− let message = match suggestion {
5752− Some(closest) => format!(
5753− "undefined attribute bundle '${}', did you mean '${}'?",
5754− name, closest
5755− ),
5756− None => format!("undefined attribute bundle '${}'", name),
5757− };
5758− Diagnostic::error(code::UNDEFINED_VARIABLE, line, message)
5759− .subject(name)
5760− .suggest(suggestion)
5761− };
5762− let diagnostic = match (&ctx.current_source, column) {
5763− ((current, Some(text)), Some(column)) if *current == line => {
5764− diagnostic.column(column).source(text.clone())
5765− }
5766− _ => diagnostic,
5767− };
5768− ctx.diagnostics.push(diagnostic);
5769−}
5770−
5771−// ---------------------------------------------------------------------------
5772−// Text segment parsing (inline {...} elements)
5773−// ---------------------------------------------------------------------------
5774−
5775−/// While a slot is filled in, each escape (see [`syntax::ESCAPES`]) is a
5776−/// private-use placeholder, U+E000 plus its place in the table, so it
5777−/// can't start a variable, a quote or an inline element. Afterwards it
5778−/// becomes what it stands for.
5779−fn protect_escapes(text: &str) -> String {
5780− if !text.contains('\\') {
5781− return text.to_string();
5782− }
5783− let mut out = String::with_capacity(text.len());
5784− let mut i = 0;
5785− while let Some(c) = text[i..].chars().next() {
5786− let len = syntax::escape_len(&text[i..]);
5787− if len == 0 {
5788− out.push(c);
5789− i += c.len_utf8();
5790− continue;
5791− }
5792− let escape = &text[i..i + len];
5793− let index = syntax::ESCAPES.iter().position(|e| *e == escape);
5794− out.extend(index.and_then(|n| char::from_u32(0xE000 + n as u32)));
5795− i += len;
5796− }
5797− out
5798−}
5799−
5800−/// The escape a placeholder stands for, as written (`\,`).
5801−fn escape_of(c: char) -> Option<&'static str> {
5802− let index = (c as u32).checked_sub(0xE000)?;
5803− syntax::ESCAPES.get(index as usize).copied()
5804−}
5805−
5806−fn restore_escapes(text: &str) -> String {
5807− text.chars()
5808− .fold(String::with_capacity(text.len()), |mut out, c| {
5809− match escape_of(c) {
5810− // What the escape stands for: what follows the backslash
5811− Some(escape) => out.push_str(&escape[1..]),
5812− None => out.push(c),
5813− }
5814− out
5815− })
5816−}
5817−
5818−/// Inside the quoted strings of a CSS value, `\"` and `\\` mean in CSS what
5819−/// they mean in htmlang, so they stay as written there.
5820−fn keep_css_string_escapes(protected: &str) -> String {
5821− let mut out = String::with_capacity(protected.len());
5822− let mut inside = false;
5823− for c in protected.chars() {
5824− match escape_of(c) {
5825− Some(escape @ ("\\\"" | "\\\\")) if inside => out.push_str(escape),
5826− _ => {
5827− if c == '"' {
5828− inside = !inside;
5829− }
5830− out.push(c);
5831− }
5832− }
5833− }
5834− out
5835−}
5836−
5837−/// Evaluate text: fill in the variables of its plain runs and build its
5838−/// inline elements. Each run is one slot, so a value can't make markup.
5839−fn text_segments(text: &syntax::Text, ctx: &mut ParseContext) -> Vec<TextSegment> {
5840− let mut segments = Vec::new();
5841− // The plain text so far, and where it starts
5842− let mut plain = String::new();
5843− let mut start: Option<syntax::Span> = None;
5844− let flush = |plain: &mut String,
5845− start: &mut Option<syntax::Span>,
5846− segments: &mut Vec<TextSegment>,
5847− ctx: &mut ParseContext| {
5848− if !plain.is_empty() {
5849− let at = start.unwrap_or(text.span);
5850− let filled = ctx.interpolate_text(plain, at.line, Some(at.column));
5851− segments.push(TextSegment::Plain(filled));
5852− plain.clear();
5853− }
5854− *start = None;
5855− };
5856− for segment in &text.segments {
5857− match segment {
5858− Segment::Plain { raw, span } => {
5859− start.get_or_insert(*span);
5860− plain.push_str(raw);
5861− }
5862− Segment::Inline(inline) => {
5863− let line = ctx.current_line;
5864− match resolve(&inline.head, inline.text.as_ref(), line, &text.raw, ctx) {
5865− Ok(resolved) => {
5866− if !inline.closed {
5867− let d = Diagnostic::warning(
5868− code::UNCLOSED_BRACKET,
5869− inline.span.line,
5870− format!(
5871− "unclosed `{{`: the inline @{} runs to the end of the line. \
5872− An inline element ends with `}}` (a brace that is text is \
5873− written `\\{{`)",
5874− inline.head.name
5875− ),
5876− );
5877− let d = at_attribute(d, Some(inline.span.column), ctx);
5878− ctx.push_once(d);
5879− }
5880− flush(&mut plain, &mut start, &mut segments, ctx);
5881− // A function called inline gets no children: its
5882− // content is the text after its attributes
5883− match Evaluator.complete(resolved, Vec::new(), ctx) {
5884− Ok(nodes) => segments.extend(inline_segments(nodes, line)),
5885− Err(mut e) => {
5886− e.source_line
5887− .get_or_insert_with(|| text.raw.as_str().into());
5888− ctx.diagnostics.push(e);
5889− }
5890− }
5891− }
5892− Err(mut e) => {
5893− // A misspelled element is an error inline too (a
5894− // brace that is text is written `\{`); the braces
5895− // stay as written
5896− e.source_line = Some(text.raw.as_str().into());
5897− ctx.diagnostics.push(e);
5898− start.get_or_insert(inline.span);
5899− plain.push('{');
5900− plain.push_str(&inline.raw);
5901− if inline.closed {
5902− plain.push('}');
5903− }
5904− }
5905− }
5906− }
5907− }
5908− }
5909− flush(&mut plain, &mut start, &mut segments, ctx);
5910− segments
5911−}
5912−
5913−/// The variable `raw` is, when it is exactly one `$name` or `${name}`.
5914−fn whole_reference(raw: &str, env: &Env) -> Option<String> {
5915− let after = raw.trim().strip_prefix('$')?;
5916− match interp::reference(after, env)? {
5917− (interp::Reference::Var(path), len) if len == after.len() => Some(path),
5918− _ => None,
5919− }
5920−}
5921−
5922−/// The attributes of `tokens` after each whole-attribute `if()` has
5923−/// chosen (see [`syntax::Choice`]), in order, into `out`. The branch not
5924−/// taken isn't evaluated; with `validate`, its attribute names are checked
5925−/// like code that doesn't run, under the prefixes `prefix` the `if()` is
5926−/// under (`hover:if(...)`).
5927−fn choose_attrs(
5928− tokens: &[syntax::Attr],
5929− prefix: &str,
5930− line_num: usize,
5931− ctx: &mut ParseContext,
5932− validate: bool,
5933− text_keys: &[String],
5934− out: &mut Vec<syntax::Attr>,
5935−) {
5936− for token in tokens {
5937− let Some(choice) = &token.choice else {
5938− out.push(token.clone());
5939− continue;
5940− };
5941− let Some(condition) = choice_shape(token, choice, line_num, ctx) else {
5942− continue;
5943− };
5944− let taken = match condition.span.line {
5945− 0 => ctx.condition(&condition.raw, line_num, None),
5946− line => ctx.condition(&condition.raw, line, Some(condition.span.column)),
5947− };
5948− let (chosen, other) = match taken {
5949− true => (choice.branches.first(), choice.branches.get(1)),
5950− false => (choice.branches.get(1), choice.branches.first()),
5951− };
5952− if let Some(other) = other {
5953− track_var_refs(&branch_text(other), &mut ctx.used_variables);
5954− if validate {
5955− check_branch(token, other, prefix, line_num, ctx, text_keys);
5956− }
5957− }
5958− if let Some(branch) = chosen {
5959− choose_attrs(
5960− branch.attrs(),
5961− prefix,
5962− line_num,
5963− ctx,
5964− validate,
5965− text_keys,
5966− out,
5967− );
5968− }
5969− }
5970−}
5971−
5972−/// Report what is wrong with the shape of `if()`: an empty condition, a
5973−/// number of branches other than one or two, text after a group's `]`.
5974−/// Returns the condition when the `if()` can be evaluated.
5975−fn choice_shape<'a>(
5976− token: &syntax::Attr,
5977− choice: &'a syntax::Choice,
5978− line_num: usize,
5979− ctx: &mut ParseContext,
5980−) -> Option<&'a syntax::Arg> {
5981− let line = if token.span.line == 0 {
5982− line_num
5983− } else {
5984− token.span.line
5985− };
5986− // The line the column points into, when it is the one being evaluated
5987− let source = |ctx: &ParseContext, diagnostic: Diagnostic, at: usize| match &ctx.current_source {
5988− (current, Some(text)) if *current == at => diagnostic.source(text.clone()),
5989− _ => diagnostic,
5990− };
5991− for branch in &choice.branches {
5992− if let syntax::Branch::Group {
5993− trailing: Some(trailing),
5994− ..
5995− } = branch
5996− {
5997− let diagnostic = source(
5998− ctx,
5999− Diagnostic::error(
6000− code::UNEXPECTED_ARGUMENT,
6001− trailing.span.line,
6002− format!(
6003− "'{}' after the `]` of a group in if(): a branch is one attribute, \
6004− one `[group]` of attributes or one `$bundle`",
6005− trailing.raw
6006− ),
6007− )
6008− .column(trailing.span.column)
6009− .subject(trailing.raw.as_str()),
6010− trailing.span.line,
6011− );
6012− ctx.push_once(diagnostic);
6013− }
6014− }
6015− match &choice.condition {
6016− Some(condition) if (1..=2).contains(&choice.branches.len()) => Some(condition),
6017− _ => {
6018− let diagnostic = source(
6019− ctx,
6020− Diagnostic::error(
6021− code::INVALID_EXPRESSION,
6022− line,
6023− format!(
6024− "`{}`: if() takes a condition and one or two branches, \
6025− `if(CONDITION, A, B)`",
6026− token.raw
6027− ),
6028− )
6029− .column(token.span.column),
6030− line,
6031− );
6032− ctx.push_once(diagnostic);
6033− None
6034− }
6035− }
6036−}
6037−
6038−/// A branch's text, for the names it uses.
6039−fn branch_text(branch: &syntax::Branch) -> String {
6040− let raws: Vec<&str> = branch.attrs().iter().map(|a| a.raw.as_str()).collect();
6041− raws.join(", ")
6042−}
6043−
6044−/// Check attributes that are never evaluated (in code that doesn't run,
6045−/// or the branch an `if()` didn't take), as far as they can be checked:
6046−/// names are, and literal values; a value with a variable depends on what
6047−/// the variable holds. Each branch of an `if()` is checked on its own.
6048−fn check_attrs(tokens: &[syntax::Attr], line: usize, ctx: &mut ParseContext, text_keys: &[String]) {
6049− parse_attr_list(&literal_attrs(tokens), line, ctx, true, text_keys);
6050− check_choices(tokens, "", line, ctx, text_keys);
6051−}
6052−
6053−/// [`check_attrs`] for a branch of the `if()` `token`, under the prefixes
6054−/// `prefix` it is under: `hover:if($on, color red, [id=x])` checks
6055−/// `hover:[id=x]`, an error whichever branch is taken.
6056−fn check_branch(
6057− token: &syntax::Attr,
6058− branch: &syntax::Branch,
6059− prefix: &str,
6060− line: usize,
6061− ctx: &mut ParseContext,
6062− text_keys: &[String],
6063−) {
6064− if prefix.is_empty() {
6065− check_attrs(branch.attrs(), line, ctx, text_keys);
6066− return;
6067− }
6068− let list = syntax::AttrList {
6069− attrs: branch.attrs().to_vec(),
6070− span: token.span,
6071− closed: true,
6072− quoted_close: None,
6073− };
6074− let grouped = syntax::Attr {
6075− key: prefix.to_string(),
6076− value: None,
6077− html: false,
6078− raw: token.raw.clone(),
6079− span: token.span,
6080− choice: None,
6081− prefixed: Some(Box::new(syntax::Prefixed {
6082− prefix: prefix.to_string(),
6083− prefix_span: token.span,
6084− target: syntax::Branch::Group {
6085− list,
6086− trailing: None,
6087− },
6088− })),
6089− };
6090− check_attrs(std::slice::from_ref(&grouped), line, ctx, text_keys);
6091−}
6092−
6093−/// [`check_attrs`] for the branches of each `if()` of `tokens`, which are
6094−/// under the prefixes `prefix`, also inside a prefixed group or as a
6095−/// prefixed `if()`.
6096−fn check_choices(
6097− tokens: &[syntax::Attr],
6098− prefix: &str,
6099− line: usize,
6100− ctx: &mut ParseContext,
6101− text_keys: &[String],
6102−) {
6103− for token in tokens {
6104− if let Some(choice) = &token.choice
6105− && choice_shape(token, choice, line, ctx).is_some()
6106− {
6107− for branch in &choice.branches {
6108− check_branch(token, branch, prefix, line, ctx, text_keys);
6109− }
6110− }
6111− if let Some(prefixed) = &token.prefixed {
6112− let inner = format!("{}{}", prefix, prefixed.prefix);
6113− check_choices(prefixed.target.attrs(), &inner, line, ctx, text_keys);
6114− }
6115− }
6116−}
6117−
6118−// ---------------------------------------------------------------------------
6119−// Post-parse validation (context-dependent warnings)
6120−// ---------------------------------------------------------------------------
6121−
6122−fn element_kind_name(kind: &ElementKind) -> String {
6123− format!("@{}", kind.name())
6124−}
6125−
6126−/// HTML elements whose start tag ends an open `<p>`: written inside a
6127−/// `@paragraph`, the browser moves them out of it. (`div` isn't here:
6128−/// inside text, htmlang writes its `<div>`s as `<span>`s.)
6129−#[rustfmt::skip]
6130−const ENDS_A_PARAGRAPH: &[&str] = &[
6131− "address", "article", "aside", "blockquote", "dd", "details", "dialog", "dl", "dt",
6132− "fieldset", "figcaption", "figure", "footer", "form", "h1", "h2", "h3", "h4", "h5", "h6",
6133− "header", "hgroup", "hr", "li", "main", "menu", "nav", "ol", "p", "pre", "search",
6134− "section", "summary", "table", "ul",
6135−];
6136−
6137−/// The HTML element `kind` is written as, if the browser would take it out
6138−/// of a `<p>`.
6139−fn ends_a_paragraph(kind: &ElementKind) -> Option<&'static str> {
6140− let html = match kind {
6141− ElementKind::Paragraph => "p",
6142− ElementKind::Tag(spec) => spec.html,
6143− _ => return None,
6144− };
6145− ENDS_A_PARAGRAPH.contains(&html).then_some(html)
6146−}
6147−
6148−/// Stricter checks for `htmlang lint`, on top of the diagnostics every
6149−/// compile reports: deep nesting, empty layout containers, and buttons
6150−/// without an explicit `type`.
6151−pub fn lint(nodes: &[Node]) -> Vec<Diagnostic> {
6152− fn walk(nodes: &[Node], depth: usize, out: &mut Vec<Diagnostic>) {
6153− for node in nodes {
6154− let Node::Element(elem) = node else { continue };
6155− let start = out.len();
6156− let mut warn = |code: &'static str, message: String| {
6157− out.push(Diagnostic::warning(code, elem.line_num, message))
6158− };
6159− if depth > 10 {
6160− warn(
6161− code::DEEP_NESTING,
6162− format!(
6163− "deeply nested element ({} levels): consider simplifying",
6164− depth
6165− ),
6166− );
6167− }
6168− // A function's body may draw with an empty element (a spacer,
6169− // a dot): only one written in the page is flagged
6170− if elem.kind.layout().is_container()
6171− && elem.children.is_empty()
6172− && elem.function.is_none()
6173− {
6174− warn(
6175− code::EMPTY_CONTAINER,
6176− format!("empty container (@{}) has no children", elem.kind.name()),
6177− );
6178− }
6179− if elem.kind.is_tag("button") && !elem.attrs.iter().any(|a| a.key == "type") {
6180− warn(
6181− code::MISSING_BUTTON_TYPE,
6182− "@button missing 'type' attribute (defaults to submit)".to_string(),
6183− );
6184− }
6185− in_function_body(elem, &mut out[start..]);
6186− walk(&elem.children, depth + 1, out);
6187− }
6188− }
6189− let mut out = Vec::new();
6190− walk(nodes, 0, &mut out);
6191− dedupe(&mut out);
6192− out
6193−}
6194−
6195−/// `in_paragraph`: the nodes are inside a `@paragraph` (and not inside a
6196−/// `@button` in it, which the browser keeps whole).
6197−fn validate_tree(
6198− nodes: &[Node],
6199− parent_kind: Option<&ElementKind>,
6200− in_paragraph: bool,
6201− diagnostics: &mut Vec<Diagnostic>,
6202−) {
6203− for node in nodes {
6204− // An element inside a line of text (`{@kbd ...}`, an inline call)
6205− // is checked like one on a line of its own
6206− if let Node::Text(segments) = node {
6207− let inline: Vec<Node> = segments
6208− .iter()
6209− .filter_map(|segment| match segment {
6210− TextSegment::Inline(elem) => Some(Node::Element(elem.clone())),
6211− _ => None,
6212− })
6213− .collect();
6214− validate_tree(&inline, parent_kind, in_paragraph, diagnostics);
6215− }
6216− if let Node::Element(elem) = node {
6217− let start = diagnostics.len();
6218− dropped_by_the_element(elem, diagnostics);
6219− if in_paragraph && let Some(html) = ends_a_paragraph(&elem.kind) {
6220− diagnostics.push(
6221− Diagnostic::warning(
6222− code::BLOCK_IN_PARAGRAPH,
6223− elem.line_num,
6224− format!(
6225− "{0} inside @paragraph: HTML ends a <p> before a <{1}>, so the \
6226− browser moves the <{1}> out of the paragraph. Put {0} after the \
6227− paragraph, or use @el, @row or @grid, which are laid out inline \
6228− in text",
6229− element_kind_name(&elem.kind),
6230− html
6231− ),
6232− )
6233− .subject(elem.kind.name()),
6234− );
6235− }
6236− for attr in &elem.attrs {
6237− let base = crate::vocab::base_attribute(&attr.key);
6238−
6239− // htmlang's words for laying out children, on an element
6240− // that doesn't lay out its children: left out (codegen)
6241− if !attr.html
6242− && crate::vocab::CONTAINER_ATTRIBUTES.contains(&base)
6243− && !elem.kind.layout().is_container()
6244− && !has_no_element(&elem.kind)
6245− && !crate::vocab::split_prefixes(&attr.key)
6246− .0
6247− .contains(&"children:")
6248− {
6249− diagnostics.push(not_a_container(&elem.kind, elem.line_num, base));
6250− }
6251−
6252− // Form-specific: placeholder only on @input/@textarea
6253− if base == "placeholder"
6254− && !(elem.kind.is_tag("input") || elem.kind.is_tag("textarea"))
6255− {
6256− diagnostics.push(Diagnostic::new(
6257− code::NO_EFFECT,
6258− Severity::Warning,
6259− elem.line_num,
6260− format!(
6261− "'placeholder' has no effect on {} (only works on @input, @textarea)",
6262− element_kind_name(&elem.kind)
6263− ),
6264− ));
6265− }
6266−
6267− // 'for' only on @label and @output
6268− if base == "for" && !(elem.kind.is_tag("label") || elem.kind.is_tag("output")) {
6269− diagnostics.push(Diagnostic::new(
6270− code::NO_EFFECT,
6271− Severity::Warning,
6272− elem.line_num,
6273− format!(
6274− "'for' has no effect on {} (only works on @label and @output)",
6275− element_kind_name(&elem.kind)
6276− ),
6277− ));
6278− }
6279−
6280− // `width=` and `height=` are HTML attributes of media and
6281− // embedded content only; elsewhere they are styles
6282− if attr.html
6283− && (base == "width" || base == "height")
6284− && !matches!(elem.kind, ElementKind::Image)
6285− && ![
6286− "video", "canvas", "iframe", "embed", "object", "input", "source",
6287− ]
6288− .iter()
6289− .any(|tag| elem.kind.is_tag(tag))
6290− {
6291− let value = attr.value.as_deref().unwrap_or("");
6292− diagnostics.push(
6293− Diagnostic::warning(
6294− code::HTML_ATTRIBUTE_FORM,
6295− elem.line_num,
6296− format!(
6297− "'{0}={1}' has no effect on {2}, which has no {0} attribute: \
6298− the style is written `{0} {1}`",
6299− base,
6300− value,
6301− element_kind_name(&elem.kind)
6302− ),
6303− )
6304− .subject(format!("{}={}", base, value)),
6305− );
6306− }
6307−
6308− // 'rows'/'cols' only on @textarea
6309− if (base == "rows" || base == "cols") && !elem.kind.is_tag("textarea") {
6310− diagnostics.push(Diagnostic::new(
6311− code::NO_EFFECT,
6312− Severity::Warning,
6313− elem.line_num,
6314− format!(
6315− "'{}' has no effect on {} (only works on @textarea)",
6316− base,
6317− element_kind_name(&elem.kind)
6318− ),
6319− ));
6320− }
6321−
6322− // Media-specific attributes only on @video/@audio
6323− if matches!(
6324− base,
6325− "controls"
6326− | "autoplay"
6327− | "loop"
6328− | "muted"
6329− | "playsinline"
6330− | "poster"
6331− | "preload"
6332− ) && !matches!(elem.kind.name(), "video" | "audio")
6333− {
6334− diagnostics.push(Diagnostic::new(
6335− code::NO_EFFECT,
6336− Severity::Warning,
6337− elem.line_num,
6338− format!(
6339− "'{}' has no effect on {} (only works on @video, @audio)",
6340− base,
6341− element_kind_name(&elem.kind)
6342− ),
6343− ));
6344− }
6345− }
6346− // Missing alt text on @image
6347− if matches!(elem.kind, ElementKind::Image) && !elem.attrs.iter().any(|a| a.key == "alt")
6348− {
6349− diagnostics.push(Diagnostic::new(
6350− code::MISSING_ALT,
6351− Severity::Warning,
6352− elem.line_num,
6353− "@image missing 'alt' attribute (accessibility)".to_string(),
6354− ));
6355− }
6356− if elem.kind.is_tag("input") && !elem.attrs.iter().any(|a| a.key == "type") {
6357− diagnostics.push(Diagnostic::new(
6358− code::MISSING_INPUT_TYPE,
6359− Severity::Warning,
6360− elem.line_num,
6361− "@input missing 'type' attribute (defaults to 'text')".to_string(),
6362− ));
6363− }
6364− if matches!(elem.kind, ElementKind::Link) {
6365− // For @link, argument is the URL, not text content
6366− let has_text = !elem.children.is_empty();
6367− if !has_text
6368− && !elem
6369− .attrs
6370− .iter()
6371− .any(|a| a.key == "aria-label" || a.key == "title")
6372− {
6373− diagnostics.push(Diagnostic::new(
6374− code::MISSING_LINK_TEXT,
6375− Severity::Warning,
6376− elem.line_num,
6377− "@link has no visible text or aria-label (accessibility)".to_string(),
6378− ));
6379− }
6380− }
6381−
6382− // Contrast ratio check for hex color pairs, each pair on the
6383− // same elements: the element's own, or those an element prefix
6384− // (`@td:`) picks out inside it
6385− let inside = |key: &str| {
6386− crate::vocab::split_prefixes(key)
6387− .0
6388− .into_iter()
6389− .find_map(crate::vocab::element_prefix)
6390− .map(str::to_string)
6391− };
6392− let mut targets: Vec<Option<String>> = Vec::new();
6393− for attr in elem.attrs.iter().filter(|a| !a.html) {
6394− let target = inside(&attr.key);
6395− if !targets.contains(&target) {
6396− targets.push(target);
6397− }
6398− }
6399− for target in targets {
6400− let color = |property: &str| {
6401− elem.attrs
6402− .iter()
6403− .filter(|a| !a.html && inside(&a.key) == target)
6404− .find(|a| crate::vocab::base_attribute(&a.key) == property)
6405− .and_then(|a| a.value.as_deref())
6406− };
6407− let (bg_color, fg_color) = (color("background"), color("color"));
6408− if let (Some(bg), Some(fg)) = (bg_color, fg_color)
6409− && let (Some(bg_rgb), Some(fg_rgb)) = (parse_hex_rgb(bg), parse_hex_rgb(fg))
6410− {
6411− let ratio = contrast_ratio(bg_rgb, fg_rgb);
6412− if ratio < 4.5 {
6413− diagnostics.push(Diagnostic::new(code::LOW_CONTRAST, Severity::Warning, elem.line_num, format!(
6414− "low contrast ratio {:.1}:1 between '{}' and '{}' (WCAG AA requires 4.5:1)",
6415− ratio, fg, bg
6416− )));
6417− }
6418− }
6419− }
6420−
6421− // @form inputs should have associated @label
6422− if matches!(elem.kind.name(), "input" | "select" | "textarea") {
6423− let has_id = elem.attrs.iter().any(|a| a.key == "id");
6424− let has_aria_label = elem
6425− .attrs
6426− .iter()
6427− .any(|a| a.key == "aria-label" || a.key == "aria-labelledby");
6428− let has_title = elem.attrs.iter().any(|a| a.key == "title");
6429− let in_label = parent_kind.is_some_and(|k| k.is_tag("label"));
6430− if !has_id && !has_aria_label && !has_title && !in_label {
6431− diagnostics.push(Diagnostic::new(code::MISSING_LABEL, Severity::Warning, elem.line_num, format!(
6432− "{} should have an 'id' (with matching @label[for]), 'aria-label', or be wrapped in @label (accessibility)",
6433− element_kind_name(&elem.kind)
6434− )));
6435− }
6436− }
6437−
6438− // @iframe should have title attribute
6439− if elem.kind.is_tag("iframe") && !elem.attrs.iter().any(|a| a.key == "title") {
6440− diagnostics.push(Diagnostic::new(
6441− code::MISSING_TITLE,
6442− Severity::Warning,
6443− elem.line_num,
6444− "@iframe missing 'title' attribute (accessibility)".to_string(),
6445− ));
6446− }
6447−
6448− // @button should have accessible text
6449− if elem.kind.is_tag("button") {
6450− let has_text = !elem.children.is_empty();
6451− let has_aria = elem.attrs.iter().any(|a| a.key == "aria-label");
6452− if !has_text && !has_aria {
6453− diagnostics.push(Diagnostic::new(
6454− code::MISSING_BUTTON_TEXT,
6455− Severity::Warning,
6456− elem.line_num,
6457− "@button has no text content or aria-label (accessibility)".to_string(),
6458− ));
6459− }
6460− }
6461−
6462− // @video should have captions or aria-label
6463− if elem.kind.is_tag("video") {
6464− let has_aria = elem
6465− .attrs
6466− .iter()
6467− .any(|a| a.key == "aria-label" || a.key == "aria-describedby");
6468− let has_track = elem
6469− .children
6470− .iter()
6471− .any(|c| matches!(c, Node::Element(e) if e.kind.is_tag("track")));
6472− if !has_aria && !has_track {
6473− diagnostics.push(Diagnostic::new(
6474− code::MISSING_CAPTIONS,
6475− Severity::Warning,
6476− elem.line_num,
6477− "@video should have aria-label or a captions @track for accessibility"
6478− .to_string(),
6479− ));
6480− }
6481− }
6482−
6483− // Tabindex > 0 is an anti-pattern
6484− if let Some(tabindex_attr) = elem.attrs.iter().find(|a| a.key == "tabindex")
6485− && let Some(ref val) = tabindex_attr.value
6486− && let Ok(n) = val.parse::<i32>()
6487− && n > 0
6488− {
6489− diagnostics.push(Diagnostic::new(code::POSITIVE_TABINDEX, Severity::Warning, elem.line_num, format!("tabindex {} is positive — avoid positive tabindex values as they disrupt natural tab order", n)));
6490− }
6491− in_function_body(elem, &mut diagnostics[start..]);
6492−
6493− // An element that ends the <p> takes what is inside it out of
6494− // the paragraph too, so only it is reported
6495− let in_paragraph = elem.kind == ElementKind::Paragraph
6496− || (in_paragraph
6497− && ends_a_paragraph(&elem.kind).is_none()
6498− && !elem.kind.is_tag("button"));
6499− validate_tree(&elem.children, Some(&elem.kind), in_paragraph, diagnostics);
6500− }
6501− }
6502−}
6503−
6504−/// What an element has no place for in HTML, which would otherwise be
6505−/// left out of the page: attributes on `@fragment` (which has no element
6506−/// of its own), styles on `@script` (which isn't shown), a body under a
6507−/// `@script` that has a src (which the browser doesn't run), an element
6508−/// under a `@script` (whose body is code), and content in a void element
6509−/// such as `@input`.
6510−fn dropped_by_the_element(elem: &Element, diagnostics: &mut Vec<Diagnostic>) {
6511− let name = elem.kind.name();
6512− let keys = |attrs: Vec<&Attribute>| {
6513− attrs
6514− .iter()
6515− .map(|a| format!("'{}'", a.key))
6516− .collect::<Vec<_>>()
6517− .join(", ")
6518− };
6519− let mut error = |code: &'static str, message: String| {
6520− diagnostics.push(Diagnostic::error(code, elem.line_num, message).subject(name))
6521− };
6522− if elem.kind == ElementKind::Fragment && !elem.attrs.is_empty() {
6523− error(
6524− code::UNEXPECTED_ARGUMENT,
6525− format!(
6526− "@fragment has no element of its own to put attributes on, so {} would go \
6527− nowhere: put them on its children, or use @el",
6528− keys(elem.attrs.iter().collect())
6529− ),
6530− );
6531− }
6532− // The leading argument given twice: an attribute passed to the root
6533− // of a function whose body gives the argument (written on one line,
6534− // it is reported where it is read, and the attribute wins there)
6535− if let Some(argument) = &elem.argument
6536− && let Some(attr) = elem
6537− .attrs
6538− .iter()
6539− .find(|a| a.html && elem.kind.arg().attributes().contains(&a.key.as_str()))
6540− {
6541− error(
6542− code::DUPLICATE_ATTRIBUTE,
6543− format!(
6544− "@{} takes '{}' as its {}, and it also has {}={}: give it once",
6545− name,
6546− argument,
6547− leading_name(&elem.kind),
6548− attr.key,
6549− attr.value.as_deref().unwrap_or("")
6550− ),
6551− );
6552− }
6553− if elem.kind.is_verbatim() {
6554− let styles: Vec<&Attribute> = elem
6555− .attrs
6556− .iter()
6557− .filter(|a| !a.html && !crate::vocab::is_html_flag(&a.key))
6558− .collect();
6559− if !styles.is_empty() {
6560− error(
6561− code::UNEXPECTED_ARGUMENT,
6562− format!(
6563− "@{} isn't shown on the page, so its styles {} would go nowhere",
6564− name,
6565− keys(styles)
6566− ),
6567− );
6568− }
6569− let src = elem.argument.clone().or_else(|| {
6570− elem.attrs
6571− .iter()
6572− .find(|a| a.html && a.key == "src")
6573− .map(|a| a.value.clone().unwrap_or_default())
6574− });
6575− if let Some(src) = src
6576− && !elem.children.is_empty()
6577− {
6578− error(
6579− code::UNEXPECTED_CONTENT,
6580− format!(
6581− "@{0} has both a src ('{1}') and a body: the browser runs only the file, \
6582− so the body would go nowhere. Put the code in {1}, or leave out the src",
6583− name, src
6584− ),
6585− );
6586− } else if let Some(Node::Element(child)) = elem
6587− .children
6588− .iter()
6589− .find(|child| matches!(child, Node::Element(_)))
6590− {
6591− // `@script > @b x`: its body is code, not elements
6592− error(
6593− code::UNEXPECTED_CONTENT,
6594− format!(
6595− "@{} holds its code as the lines under it, kept as written, so @{} would \
6596− go nowhere",
6597− name,
6598− child.kind.name()
6599− ),
6600− );
6601− }
6602− }
6603− if elem.kind != ElementKind::Image && elem.attrs.iter().any(|a| !a.html && a.key == "inline") {
6604− error(
6605− code::UNEXPECTED_ARGUMENT,
6606− format!(
6607− "`inline` puts an image's file into the page, and @{} has none: it only \
6608− works on @image",
6609− name
6610− ),
6611− );
6612− }
6613− if elem.kind.layout() == Layout::Void && !elem.children.is_empty() {
6614− error(
6615− code::UNEXPECTED_CONTENT,
6616− format!(
6617− "@{} takes no content: it is an element without a closing tag, so its text \
6618− and indented lines would go nowhere",
6619− name
6620− ),
6621− );
6622− }
6623−}
6624−
6625−/// `@fragment`, `@script`, `@children` and `@slot`, whose attributes are
6626−/// reported on their own (see `dropped_by_the_element`).
6627−fn has_no_element(kind: &ElementKind) -> bool {
6628− matches!(
6629− kind,
6630− ElementKind::Fragment | ElementKind::Children | ElementKind::Slot(_)
6631− ) || kind.is_verbatim()
6632−}
6633−
6634−/// htmlang's word `word` for laying out children (`spacing`, `wrap`,
6635−/// `grid-cols`, `grid-rows`) on an element that doesn't lay out its
6636−/// children: an error, and the word is left out.
6637−fn not_a_container(kind: &ElementKind, line: usize, word: &str) -> Diagnostic {
6638− let name = element_kind_name(kind);
6639− let (what, instead) = match kind.layout() {
6640− Layout::Text => (
6641− "is text, whose lines and children flow together with no gap between them",
6642− "; to space the children out, put them in an @el or @row",
6643− ),
6644− Layout::Void => ("has no content to lay out", ""),
6645− _ => (
6646− "keeps HTML's own layout",
6647− "; for a flex layout of your own, write CSS, such as `display flex, gap 8`",
6648− ),
6649− };
6650− Diagnostic::error(
6651− code::NO_EFFECT,
6652− line,
6653− format!(
6654− "'{0}' can't go on {1}: {1} {2}. `{0}` works on a row, column or grid \
6655− (@el, @row, @grid, @section, ...){3}",
6656− word, name, what, instead
6657− ),
6658− )
6659− .subject(word)
6660−}
6661−
6662−/// Diagnostics about an element a function's body wrote are reported at
6663−/// the call (see `belongs_to_call`); say which body the element is in.
6664−fn in_function_body(elem: &Element, diagnostics: &mut [Diagnostic]) {
6665− if let Some(function) = &elem.function {
6666− for d in diagnostics {
6667− d.message = format!("{}\n in the body of @{}", d.message, function);
6668− }
6669− }
6670−}
6671−
6672−/// Report each diagnostic once: a line that runs many times (in a loop, in
6673−/// a function called from one place many times) reports its problems once.
6674−fn dedupe(diagnostics: &mut Vec<Diagnostic>) {
6675− let mut seen = HashSet::new();
6676− diagnostics.retain(|d| {
6677− seen.insert((
6678− d.code,
6679− d.line,
6680− d.column,
6681− d.message.clone(),
6682− d.severity as u8,
6683− ))
6684− });
6685−}
6686−
6687−fn relative_luminance(r: u8, g: u8, b: u8) -> f64 {
6688− fn linearize(c: u8) -> f64 {
6689− let s = c as f64 / 255.0;
6690− if s <= 0.03928 {
6691− s / 12.92
6692− } else {
6693− ((s + 0.055) / 1.055).powf(2.4)
6694− }
6695− }
6696− 0.2126 * linearize(r) + 0.7152 * linearize(g) + 0.0722 * linearize(b)
6697−}
6698−
6699−/// The red, green and blue of a `#rgb` or `#rrggbb` colour.
6700−fn parse_hex_rgb(s: &str) -> Option<(u8, u8, u8)> {
6701− let s = s.strip_prefix('#')?;
6702− if !s.bytes().all(|b| b.is_ascii_hexdigit()) {
6703− return None;
6704− }
6705− let channel = |i: usize, len: usize| u8::from_str_radix(&s[i..i + len], 16).ok();
6706− match s.len() {
6707− 3 => Some((
6708− channel(0, 1)? * 17,
6709− channel(1, 1)? * 17,
6710− channel(2, 1)? * 17,
6711− )),
6712− 6 => Some((channel(0, 2)?, channel(2, 2)?, channel(4, 2)?)),
6713− _ => None,
6714− }
6715−}
6716−
6717−fn contrast_ratio(c1: (u8, u8, u8), c2: (u8, u8, u8)) -> f64 {
6718− let l1 = relative_luminance(c1.0, c1.1, c1.2);
6719− let l2 = relative_luminance(c2.0, c2.1, c2.2);
6720− let (lighter, darker) = if l1 > l2 { (l1, l2) } else { (l2, l1) };
6721− (lighter + 0.05) / (darker + 0.05)
6722−}
6723−
6724−/// `@image [inline] icon.svg` becomes the SVG's markup, with `width`,
6725−/// `height`, `color` / `fill` and the HTML attributes (`class=`, `id=`,
6726−/// `aria-label=`, ...) applied to the `<svg>` tag; any other attribute is
6727−/// an error. Other nodes are returned unchanged.
6728−fn inline_svg(node: Node, line_num: usize, ctx: &mut ParseContext) -> Node {
6729− let Node::Element(elem) = &node else {
6730− return node;
6731− };
6732− let inline = elem.kind == ElementKind::Image
6733− && elem.attrs.iter().any(|a| a.key == "inline" && !a.html)
6734− && elem.argument.as_deref().is_some_and(|src| !src.is_empty());
6735− if !inline {
6736− return node;
6737− }
6738− // A raster image: its file, read relative to this one, as a `data:` URI
6739− if !elem
6740− .argument
6741− .as_deref()
6742− .is_some_and(|src| src.ends_with(".svg"))
6743− {
6744− let Node::Element(mut elem) = node else {
6745− return node;
6746− };
6747− let filename = elem.argument.clone().unwrap_or_default();
6748− let resolved = ctx.resolve(&filename);
6749− match std::fs::read(&resolved) {
6750− Ok(data) => {
6751− elem.argument = Some(crate::codegen::data_uri(&filename, &data));
6752− ctx.included_files.push(resolved);
6753− }
6754− Err(e) => ctx.diagnostics.push(Diagnostic::new(
6755− code::UNREADABLE_FILE,
6756− Severity::Error,
6757− line_num,
6758− format!(
6759− "cannot load image '{}' to put it into the page: {}",
6760− filename, e
6761− ),
6762− )),
6763− }
6764− return Node::Element(elem);
6765− }
6766− let filename = elem.argument.clone().unwrap_or_default();
6767− let resolved = match &ctx.base_path {
6768− Some(base) => base.join(&filename),
6769− None => PathBuf::from(&filename),
6770− };
6771− let mut svg = match std::fs::read_to_string(&resolved) {
6772− Ok(text) => text.trim().to_string(),
6773− Err(e) => {
6774− ctx.diagnostics.push(Diagnostic::new(
6775− code::UNREADABLE_FILE,
6776− Severity::Error,
6777− line_num,
6778− format!("cannot load SVG '{}': {}", filename, e),
6779− ));
6780− return node;
6781− }
6782− };
6783− ctx.included_files.push(resolved);
6784− // The file's markup has no class of its own, so a style reaches it only
6785− // as one of the root's attributes: anything else is reported, never
6786− // left out silently
6787− let mut left_out: Vec<String> = Vec::new();
6788− // The styles go in the root's `style=`, where a length takes its unit
6789− // and `var(--name)` works, as in any CSS
6790− let mut style: Vec<String> = Vec::new();
6791− for attr in &elem.attrs {
6792− let target = match (attr.key.as_str(), attr.html, &attr.value) {
6793− ("inline", false, None) | ("src", true, _) => continue,
6794− // `fill` and `shrink` are layout words, which need a class
6795− ("width" | "height", false, Some(value))
6796− if matches!(value.as_str(), "fill" | "shrink") =>
6797− {
6798− left_out.push(format!("{} {}", attr.key, value));
6799− continue;
6800− }
6801− ("width" | "height", false, Some(value)) => {
6802− let value = crate::vocab::with_px(&attr.key, value);
6803− style.push(format!("{}:{}", attr.key, value));
6804− continue;
6805− }
6806− ("color" | "fill", false, Some(value)) => {
6807− style.push(format!("fill:{}", value));
6808− continue;
6809− }
6810− ("style", true, Some(value)) => {
6811− style.insert(0, value.trim().trim_end_matches(';').to_string());
6812− continue;
6813− }
6814− ("alt", true, _) => {
6815− left_out.push("alt".to_string());
6816− continue;
6817− }
6818− (key, true, Some(_)) => key,
6819− (key, false, None) if crate::vocab::is_html_flag(key) => key,
6820− _ => {
6821− left_out.push(attr.key.clone());
6822− continue;
6823− }
6824− };
6825− let value = attr.value.as_deref().unwrap_or("");
6826− svg = set_svg_attr(&svg, target, &html_escape_md(value));
6827− }
6828− if !style.is_empty() {
6829− // After the file's own `style=`, which stays: these come later, so
6830− // they win where both set a property
6831− let mut value = html_escape_md(&style.join(";"));
6832− if let Some(own) = svg_attr_value(&svg, "style")
6833− .map(|range| svg[range].trim().trim_end_matches(';').to_string())
6834− .filter(|own| !own.is_empty())
6835− {
6836− value = format!("{};{}", own, value);
6837− }
6838− svg = set_svg_attr(&svg, "style", &value);
6839− }
6840− if !left_out.is_empty() {
6841− let alt = left_out.iter().any(|name| name == "alt");
6842− let names = left_out
6843− .iter()
6844− .map(|name| format!("'{}'", name))
6845− .collect::<Vec<_>>()
6846− .join(", ");
6847− let mut message = format!(
6848− "{} can't go on an inline SVG: `@image [inline]` puts the file's own markup into the page, which takes `width` and `height` as lengths, `color` or `fill` (as its fill) and HTML attributes (`class=`, `aria-label=`, ...)",
6849− names
6850− );
6851− if alt {
6852− message.push_str("; an SVG has no alt text: name it with `aria-label=` and `role=img`");
6853− }
6854− ctx.diagnostics.push(Diagnostic::new(
6855− code::UNEXPECTED_ARGUMENT,
6856− Severity::Error,
6857− line_num,
6858− message,
6859− ));
6860− }
6861− Node::Raw(svg)
6862−}
6863−
6864−// ---------------------------------------------------------------------------
6865−// Variable usage tracking
6866−// ---------------------------------------------------------------------------
6867−
6868−/// Record the names a string refers to (by syntax) as used.
6869−fn track_var_refs(input: &str, used: &mut HashSet<String>) {
6870− if input.contains('$') {
6871− used.extend(interp::names(input).into_iter().map(String::from));
6872− }
6873−}
6874−
6875−// ---------------------------------------------------------------------------
6876−// Unused definition warnings
6877−// ---------------------------------------------------------------------------
6878−
6879−/// Warn about definitions nothing uses, except `exported` ones (the
6880−/// definitions of a library, for the files that include it).
6881−fn check_unused(ctx: &mut ParseContext, exported: &HashSet<String>) {
6882− // Check unused @let variables
6883− for (name, &line) in &ctx.let_lines {
6884− if exported.contains(name) {
6885− // A library's names are for other files (a custom property
6886− // isn't a variable, so it is never listed here)
6887− continue;
6888− }
6889− if !ctx.used_variables.contains(name) {
6890− ctx.diagnostics.push(
6891− Diagnostic::new(
6892− code::UNUSED_VARIABLE,
6893− Severity::Warning,
6894− line,
6895− format!("unused variable '${}' (defined but never referenced)", name),
6896− )
6897− .subject(name.as_str()),
6898− );
6899− }
6900− }
6901−
6902− // Check unused attribute bundles (@let name [...]). A `$name` in code
6903− // that doesn't run (an `if()` branch or `@if` not taken) counts too.
6904− for (name, &line) in &ctx.define_lines {
6905− if !ctx.used_defines.contains(name)
6906− && !ctx.used_variables.contains(name)
6907− && !exported.contains(name)
6908− {
6909− ctx.diagnostics.push(
6910− Diagnostic::new(
6911− code::UNUSED_BUNDLE,
6912− Severity::Warning,
6913− line,
6914− format!(
6915− "unused attribute bundle '${}' (defined but never referenced)",
6916− name
6917− ),
6918− )
6919− .subject(name.as_str()),
6920− );
6921− }
6922− }
6923−
6924− // Check unused functions (@let name ... with body)
6925− for (name, &line) in &ctx.fn_lines {
6926− if !ctx.used_functions.contains(name) && !exported.contains(name) {
6927− ctx.diagnostics.push(
6928− Diagnostic::new(
6929− code::UNUSED_FUNCTION,
6930− Severity::Warning,
6931− line,
6932− format!("unused function '@{}' (defined but never called)", name),
6933− )
6934− .subject(name.as_str()),
6935− );
6936− }
6937− }
6938−}
6939−
6940−// ---------------------------------------------------------------------------
6941−// Minimal JSON parser for @data directive
6942−// ---------------------------------------------------------------------------
6943−
6944−#[derive(Debug, Clone)]
6945−enum JsonValue {
6946− Null,
6947− Bool(bool),
6948− Number(String),
6949− Str(String),
6950− Array(Vec<JsonValue>),
6951− Object(Vec<(String, JsonValue)>),
6952−}
6953−
6954−/// Parse JSON with an error message indicating where parsing failed.
6955−fn parse_json_with_error(input: &str) -> Result<JsonValue, String> {
6956− let trimmed = input.trim();
6957− if trimmed.is_empty() {
6958− return Err("empty input".to_string());
6959− }
6960− let chars: Vec<char> = trimmed.chars().collect();
6961− match parse_json_value(&chars, 0) {
6962− Some((val, _)) => Ok(val),
6963− None => {
6964− // Find approximate error position by parsing as far as possible
6965− let mut deepest = 0usize;
6966− fn probe(chars: &[char], pos: usize, deepest: &mut usize) {
6967− let mut p = pos;
6968− while p < chars.len() {
6969− if p > *deepest {
6970− *deepest = p;
6971− }
6972− match chars[p] {
6973− '{' | '[' => {
6974− p += 1;
6975− probe(chars, p, deepest);
6976− return;
6977− }
6978− '"' => {
6979− p += 1;
6980− while p < chars.len() && chars[p] != '"' {
6981− if chars[p] == '\\' {
6982− p += 1;
6983− }
6984− p += 1;
6985− }
6986− if p < chars.len() {
6987− p += 1;
6988− }
6989− if p > *deepest {
6990− *deepest = p;
6991− }
6992− return;
6993− }
6994− _ => {
6995− p += 1;
6996− }
6997− }
6998− }
6999− }
7000− probe(&chars, 0, &mut deepest);
7001− // Convert char position to line:col
7002− let prefix: String = chars[..deepest.min(chars.len())].iter().collect();
7003− let line = prefix.chars().filter(|&c| c == '\n').count() + 1;
7004− let col = prefix
7005− .rfind('\n')
7006− .map_or(prefix.len(), |p| prefix.len() - p - 1)
7007− + 1;
7008− let context: String = chars[deepest.saturating_sub(20)..deepest.min(chars.len())]
7009− .iter()
7010− .collect();
7011− Err(format!(
7012− "at line {}:{} near \"{}\"",
7013− line,
7014− col,
7015− context.trim()
7016− ))
7017− }
7018− }
7019−}
7020−
7021−fn parse_json_value(chars: &[char], mut pos: usize) -> Option<(JsonValue, usize)> {
7022− pos = skip_ws(chars, pos);
7023− if pos >= chars.len() {
7024− return None;
7025− }
7026− match chars[pos] {
7027− '"' => {
7028− let (s, p) = parse_json_string(chars, pos)?;
7029− Some((JsonValue::Str(s), p))
7030− }
7031− '{' => parse_json_object(chars, pos),
7032− '[' => parse_json_array(chars, pos),
7033− 't' => {
7034− if chars.get(pos..pos + 4)?.iter().collect::<String>() == "true" {
7035− Some((JsonValue::Bool(true), pos + 4))
7036− } else {
7037− None
7038− }
7039− }
7040− 'f' => {
7041− if chars.get(pos..pos + 5)?.iter().collect::<String>() == "false" {
7042− Some((JsonValue::Bool(false), pos + 5))
7043− } else {
7044− None
7045− }
7046− }
7047− 'n' => {
7048− if chars.get(pos..pos + 4)?.iter().collect::<String>() == "null" {
7049− Some((JsonValue::Null, pos + 4))
7050− } else {
7051− None
7052− }
7053− }
7054− c if c == '-' || c.is_ascii_digit() => {
7055− let start = pos;
7056− if chars[pos] == '-' {
7057− pos += 1;
7058− }
7059− while pos < chars.len()
7060− && (chars[pos].is_ascii_digit()
7061− || chars[pos] == '.'
7062− || chars[pos] == 'e'
7063− || chars[pos] == 'E'
7064− || chars[pos] == '+'
7065− || chars[pos] == '-')
7066− {
7067− if (chars[pos] == '+' || chars[pos] == '-')
7068− && pos > start + 1
7069− && chars[pos - 1] != 'e'
7070− && chars[pos - 1] != 'E'
7071− {
7072− break;
7073− }
7074− pos += 1;
7075− }
7076− let num: String = chars[start..pos].iter().collect();
7077− Some((JsonValue::Number(num), pos))
7078− }
7079− _ => None,
7080− }
7081−}
7082−
7083−fn parse_json_string(chars: &[char], mut pos: usize) -> Option<(String, usize)> {
7084− if chars.get(pos) != Some(&'"') {
7085− return None;
7086− }
7087− pos += 1;
7088− let mut s = String::new();
7089− while pos < chars.len() && chars[pos] != '"' {
7090− if chars[pos] == '\\' && pos + 1 < chars.len() {
7091− pos += 1;
7092− match chars[pos] {
7093− '"' | '\\' | '/' => s.push(chars[pos]),
7094− 'n' => s.push('\n'),
7095− 't' => s.push('\t'),
7096− 'r' => s.push('\r'),
7097− 'b' => s.push('\u{8}'),
7098− 'f' => s.push('\u{c}'),
7099− 'u' => {
7100− let hex4 = |at: usize| -> Option<u32> {
7101− let digits: String = chars.get(at..at + 4)?.iter().collect();
7102− u32::from_str_radix(&digits, 16).ok()
7103− };
7104− let hi = hex4(pos + 1)?;
7105− pos += 4;
7106− let code = if (0xD800..0xDC00).contains(&hi)
7107− && chars.get(pos + 1) == Some(&'\\')
7108− && chars.get(pos + 2) == Some(&'u')
7109− && let Some(lo) = hex4(pos + 3)
7110− && (0xDC00..0xE000).contains(&lo)
7111− {
7112− pos += 6;
7113− 0x10000 + ((hi - 0xD800) << 10) + (lo - 0xDC00)
7114− } else {
7115− hi
7116− };
7117− s.push(char::from_u32(code).unwrap_or('\u{FFFD}'));
7118− }
7119− _ => {
7120− s.push('\\');
7121− s.push(chars[pos]);
7122− }
7123− }
7124− } else {
7125− s.push(chars[pos]);
7126− }
7127− pos += 1;
7128− }
7129− if pos < chars.len() {
7130− pos += 1; // closing quote
7131− }
7132− Some((s, pos))
7133−}
7134−
7135−fn parse_json_object(chars: &[char], mut pos: usize) -> Option<(JsonValue, usize)> {
7136− pos += 1; // skip '{'
7137− pos = skip_ws(chars, pos);
7138− let mut pairs = Vec::new();
7139− if pos < chars.len() && chars[pos] == '}' {
7140− return Some((JsonValue::Object(pairs), pos + 1));
7141− }
7142− loop {
7143− pos = skip_ws(chars, pos);
7144− let (key, p) = parse_json_string(chars, pos)?;
7145− pos = skip_ws(chars, p);
7146− if pos >= chars.len() || chars[pos] != ':' {
7147− return None;
7148− }
7149− pos += 1;
7150− let (val, p) = parse_json_value(chars, pos)?;
7151− pos = p;
7152− pairs.push((key, val));
7153− pos = skip_ws(chars, pos);
7154− if pos >= chars.len() {
7155− break;
7156− }
7157− if chars[pos] == '}' {
7158− pos += 1;
7159− break;
7160− }
7161− if chars[pos] == ',' {
7162− pos += 1;
7163− }
7164− }
7165− Some((JsonValue::Object(pairs), pos))
7166−}
7167−
7168−fn parse_json_array(chars: &[char], mut pos: usize) -> Option<(JsonValue, usize)> {
7169− pos += 1; // skip '['
7170− pos = skip_ws(chars, pos);
7171− let mut items = Vec::new();
7172− if pos < chars.len() && chars[pos] == ']' {
7173− return Some((JsonValue::Array(items), pos + 1));
7174− }
7175− loop {
7176− let (val, p) = parse_json_value(chars, pos)?;
7177− pos = p;
7178− items.push(val);
7179− pos = skip_ws(chars, pos);
7180− if pos >= chars.len() {
7181− break;
7182− }
7183− if chars[pos] == ']' {
7184− pos += 1;
7185− break;
7186− }
7187− if chars[pos] == ',' {
7188− pos += 1;
7189− }
7190− }
7191− Some((JsonValue::Array(items), pos))
7192−}
7193−
7194−fn skip_ws(chars: &[char], mut pos: usize) -> usize {
7195− while pos < chars.len() && chars[pos].is_ascii_whitespace() {
7196− pos += 1;
7197− }
7198− pos
7199−}
7200−
7201−/// A JSON value as an htmlang value: an object is a record, an array a
7202−/// list, a string text (never quoted text), `null` empty. A number keeps
7203−/// the text it is written with (`1.50`), and reads as a number.
7204−fn json_value(json: JsonValue) -> Value {
7205− match json {
7206− JsonValue::Null => Value::empty(),
7207− JsonValue::Bool(b) => Value::Bool(b),
7208− JsonValue::Number(n) | JsonValue::Str(n) => Value::Str(n),
7209− JsonValue::Array(items) => Value::list(items.into_iter().map(json_value).collect()),
7210− JsonValue::Object(pairs) => Value::Record(Rc::new(
7211− pairs
7212− .into_iter()
7213− .map(|(key, value)| (key, json_value(value)))
7214− .collect(),
7215− )),
7216− }
7217−}
7218−
7219−// ---------------------------------------------------------------------------
7220−// SVG attribute injection helper
7221−// ---------------------------------------------------------------------------
7222−
7223−/// Where the root `<svg ...>` tag's `attr_name="..."` value is, as a byte
7224−/// range of `svg`. Only the opening tag is read, so a child's attribute is
7225−/// never found, and the name must follow whitespace, so `width` doesn't
7226−/// match `stroke-width`.
7227−fn svg_attr_value(svg: &str, attr_name: &str) -> Option<std::ops::Range<usize>> {
7228− let tag_start = svg.find("<svg")?;
7229− let tag_end = svg[tag_start..]
7230− .find('>')
7231− .map(|p| tag_start + p)
7232− .unwrap_or(svg.len());
7233− let tag = &svg[tag_start..tag_end];
7234− let pattern = format!("{}=\"", attr_name);
7235− let (pos, _) = tag.match_indices(&pattern).find(|(pos, _)| {
7236− tag[..*pos]
7237− .chars()
7238− .next_back()
7239− .is_some_and(char::is_whitespace)
7240− })?;
7241− let value_start = tag_start + pos + pattern.len();
7242− let end = svg[value_start..tag_end].find('"')?;
7243− Some(value_start..value_start + end)
7244−}
7245−
7246−fn set_svg_attr(svg: &str, attr_name: &str, value: &str) -> String {
7247− // Only the opening <svg ...> tag is touched, so child attributes such as
7248− // `stroke-width` are left alone.
7249− let Some(tag_start) = svg.find("<svg") else {
7250− return svg.to_string();
7251− };
7252− let tag_end = svg[tag_start..]
7253− .find('>')
7254− .map(|p| tag_start + p)
7255− .unwrap_or(svg.len());
7256−
7257− // Replace an existing attribute
7258− if let Some(existing) = svg_attr_value(svg, attr_name) {
7259− let mut result = String::with_capacity(svg.len());
7260− result.push_str(&svg[..existing.start]);
7261− result.push_str(value);
7262− result.push_str(&svg[existing.end..]);
7263− return result;
7264− }
7265−
7266− // Otherwise inject it into the opening tag (before a self-closing `/`).
7267− let insert_at = if svg[..tag_end].ends_with('/') {
7268− tag_end - 1
7269− } else {
7270− tag_end
7271− };
7272− let mut result = String::with_capacity(svg.len() + attr_name.len() + value.len() + 4);
7273− result.push_str(svg[..insert_at].trim_end());
7274− result.push(' ');
7275− result.push_str(attr_name);
7276− result.push_str("=\"");
7277− result.push_str(value);
7278− result.push('"');
7279− result.push_str(&svg[insert_at..]);
7280− result
7281−}
7282−
7283−// ---------------------------------------------------------------------------
7284−// Markdown → HTML conversion (minimal subset)
7285−// ---------------------------------------------------------------------------
7286−
7287−fn markdown_to_html(lines: &[String]) -> String {
7288− let mut html = String::new();
7289− // Tag of the list currently open ("ul" or "ol"), if any.
7290− let mut list: Option<&'static str> = None;
7291− let mut in_code_block = false;
7292− let mut code_lang = String::new();
7293− let mut code_buf = String::new();
7294− let mut para_buf = String::new();
7295−
7296− let flush_para = |para: &mut String, out: &mut String| {
7297− let trimmed = para.trim();
7298− if !trimmed.is_empty() {
7299− out.push_str("<p>");
7300− out.push_str(&md_inline(trimmed));
7301− out.push_str("</p>\n");
7302− }
7303− para.clear();
7304− };
7305− let close_list = |list: &mut Option<&'static str>, out: &mut String| {
7306− if let Some(tag) = list.take() {
7307− out.push_str(&format!("</{}>\n", tag));
7308− }
7309− };
7310− let open_list = |list: &mut Option<&'static str>, tag: &'static str, out: &mut String| {
7311− if *list != Some(tag) {
7312− if let Some(prev) = list.take() {
7313− out.push_str(&format!("</{}>\n", prev));
7314− }
7315− out.push_str(&format!("<{}>\n", tag));
7316− *list = Some(tag);
7317− }
7318− };
7319−
7320− for line in lines {
7321− let trimmed = line.trim();
7322−
7323− // Fenced code blocks
7324− if let Some(after_fence) = trimmed.strip_prefix("```") {
7325− if in_code_block {
7326− html.push_str("<pre><code");
7327− if !code_lang.is_empty() {
7328− html.push_str(&format!(" class=\"language-{}\"", code_lang));
7329− }
7330− html.push('>');
7331− html.push_str(&html_escape_md(&code_buf));
7332− html.push_str("</code></pre>\n");
7333− code_buf.clear();
7334− code_lang.clear();
7335− in_code_block = false;
7336− } else {
7337− flush_para(&mut para_buf, &mut html);
7338− close_list(&mut list, &mut html);
7339− code_lang = after_fence.trim().to_string();
7340− in_code_block = true;
7341− }
7342− continue;
7343− }
7344− if in_code_block {
7345− if !code_buf.is_empty() {
7346− code_buf.push('\n');
7347− }
7348− // Keep indentation inside code blocks.
7349− code_buf.push_str(line.trim_end());
7350− continue;
7351− }
7352−
7353− // Blank line ends paragraph
7354− if trimmed.is_empty() {
7355− flush_para(&mut para_buf, &mut html);
7356− close_list(&mut list, &mut html);
7357− continue;
7358− }
7359−
7360− // Headings
7361− let heading_level = trimmed.bytes().take_while(|&b| b == b'#').count();
7362− if (1..=6).contains(&heading_level) && trimmed.as_bytes().get(heading_level) == Some(&b' ')
7363− {
7364− flush_para(&mut para_buf, &mut html);
7365− close_list(&mut list, &mut html);
7366− let text = &trimmed[heading_level + 1..];
7367− html.push_str(&format!(
7368− "<h{}>{}</h{}>\n",
7369− heading_level,
7370− md_inline(text),
7371− heading_level
7372− ));
7373− continue;
7374− }
7375−
7376− // Horizontal rule (checked before list items so `---`/`***` aren't
7377− // mistaken for bullets)
7378− if trimmed == "---" || trimmed == "***" || trimmed == "___" {
7379− flush_para(&mut para_buf, &mut html);
7380− close_list(&mut list, &mut html);
7381− html.push_str("<hr>\n");
7382− continue;
7383− }
7384−
7385− // Unordered list items
7386− if (trimmed.starts_with("- ") || trimmed.starts_with("* ")) && trimmed.len() > 2 {
7387− flush_para(&mut para_buf, &mut html);
7388− open_list(&mut list, "ul", &mut html);
7389− html.push_str(&format!("<li>{}</li>\n", md_inline(&trimmed[2..])));
7390− continue;
7391− }
7392−
7393− // Ordered list items
7394− if let Some(dot_pos) = trimmed.find(". ")
7395− && (1..=3).contains(&dot_pos)
7396− && trimmed[..dot_pos].chars().all(|c| c.is_ascii_digit())
7397− {
7398− flush_para(&mut para_buf, &mut html);
7399− open_list(&mut list, "ol", &mut html);
7400− html.push_str(&format!(
7401− "<li>{}</li>\n",
7402− md_inline(&trimmed[dot_pos + 2..])
7403− ));
7404− continue;
7405− }
7406−
7407− // Blockquote
7408− if let Some(quote_content) = trimmed.strip_prefix("> ") {
7409− flush_para(&mut para_buf, &mut html);
7410− close_list(&mut list, &mut html);
7411− html.push_str(&format!(
7412− "<blockquote><p>{}</p></blockquote>\n",
7413− md_inline(quote_content)
7414− ));
7415− continue;
7416− }
7417−
7418− // Otherwise, accumulate paragraph text
7419− close_list(&mut list, &mut html);
7420− if !para_buf.is_empty() {
7421− para_buf.push(' ');
7422− }
7423− para_buf.push_str(trimmed);
7424− }
7425−
7426− // Flush remaining
7427− close_list(&mut list, &mut html);
7428− flush_para(&mut para_buf, &mut html);
7429−
7430− html
7431−}
7432−
7433−fn md_inline(text: &str) -> String {
7434− let mut result = String::new();
7435− let chars: Vec<char> = text.chars().collect();
7436− let mut i = 0;
7437−
7438− while i < chars.len() {
7439− // Bold: **text** or __text__
7440− if i + 1 < chars.len()
7441− && ((chars[i] == '*' && chars[i + 1] == '*')
7442− || (chars[i] == '_' && chars[i + 1] == '_'))
7443− {
7444− let marker = chars[i];
7445− if let Some(end) = find_closing_double(&chars, i + 2, marker) {
7446− let inner: String = chars[i + 2..end].iter().collect();
7447− result.push_str("<strong>");
7448− result.push_str(&md_inline(&inner));
7449− result.push_str("</strong>");
7450− i = end + 2;
7451− continue;
7452− }
7453− }
7454− // Italic: *text* or _text_
7455− if (chars[i] == '*' || chars[i] == '_') && i + 1 < chars.len() && chars[i + 1] != chars[i] {
7456− let marker = chars[i];
7457− if let Some(end) = find_closing_single(&chars, i + 1, marker) {
7458− let inner: String = chars[i + 1..end].iter().collect();
7459− result.push_str("<em>");
7460− result.push_str(&md_inline(&inner));
7461− result.push_str("</em>");
7462− i = end + 1;
7463− continue;
7464− }
7465− }
7466− // Inline code: `text`
7467− if chars[i] == '`'
7468− && let Some(end) = chars[i + 1..].iter().position(|&c| c == '`')
7469− {
7470− let inner: String = chars[i + 1..i + 1 + end].iter().collect();
7471− result.push_str("<code>");
7472− result.push_str(&html_escape_md(&inner));
7473− result.push_str("</code>");
7474− i = i + 2 + end;
7475− continue;
7476− }
7477− // Links: [text](url)
7478− if chars[i] == '['
7479− && let Some(close_bracket) = chars[i + 1..].iter().position(|&c| c == ']')
7480− {
7481− let after = i + 1 + close_bracket + 1;
7482− if after < chars.len()
7483− && chars[after] == '('
7484− && let Some(close_paren) = chars[after + 1..].iter().position(|&c| c == ')')
7485− {
7486− let text: String = chars[i + 1..i + 1 + close_bracket].iter().collect();
7487− let url: String = chars[after + 1..after + 1 + close_paren].iter().collect();
7488− result.push_str(&format!(
7489− "<a href=\"{}\">{}</a>",
7490− html_escape_md(&url),
7491− md_inline(&text)
7492− ));
7493− i = after + 2 + close_paren;
7494− continue;
7495− }
7496− }
7497− result.push(chars[i]);
7498− i += 1;
7499− }
7500−
7501− result
7502−}
7503−
7504−fn find_closing_double(chars: &[char], start: usize, marker: char) -> Option<usize> {
7505− let mut i = start;
7506− while i + 1 < chars.len() {
7507− if chars[i] == marker && chars[i + 1] == marker {
7508− return Some(i);
7509− }
7510− i += 1;
7511− }
7512− None
7513−}
7514−
7515−fn find_closing_single(chars: &[char], start: usize, marker: char) -> Option<usize> {
7516− (start..chars.len()).find(|&i| chars[i] == marker)
7517−}
7518−
7519−/// Simple glob matching supporting `*` as wildcard for any characters and `?` for a single character.
7520−fn glob_match(pattern: &str, text: &str) -> bool {
7521− let mut pi = 0;
7522− let mut ti = 0;
7523− let pb = pattern.as_bytes();
7524− let tb = text.as_bytes();
7525− let mut star_pi = usize::MAX;
7526− let mut star_ti = 0;
7527− while ti < tb.len() {
7528− if pi < pb.len() && (pb[pi] == b'?' || pb[pi] == tb[ti]) {
7529− pi += 1;
7530− ti += 1;
7531− } else if pi < pb.len() && pb[pi] == b'*' {
7532− star_pi = pi;
7533− star_ti = ti;
7534− pi += 1;
7535− } else if star_pi != usize::MAX {
7536− pi = star_pi + 1;
7537− star_ti += 1;
7538− ti = star_ti;
7539− } else {
7540− return false;
7541− }
7542− }
7543− while pi < pb.len() && pb[pi] == b'*' {
7544− pi += 1;
7545− }
7546− pi == pb.len()
7547−}
7548−
7549−fn html_escape_md(s: &str) -> String {
7550− s.replace('&', "&")
7551− .replace('<', "<")
7552− .replace('>', ">")
7553− .replace('"', """)
7554−}
7555−
7556−#[cfg(test)]
7557−mod tests {
7558− use super::*;
7559−
7560− fn parse_ok(src: &str) -> ParseResult {
7561− let r = parse(src);
7562− assert!(
7563− r.diagnostics.iter().all(|d| d.severity != Severity::Error),
7564− "unexpected error diagnostics: {:?}",
7565− r.diagnostics,
7566− );
7567− r
7568− }
7569−
7570− #[test]
7571− fn parses_empty_input() {
7572− let r = parse("");
7573− assert!(r.document.nodes.is_empty());
7574− assert!(r.diagnostics.is_empty());
7575− }
7576−
7577− #[test]
7578− fn parses_bare_text_node() {
7579− let r = parse_ok("Hello world\n");
7580− assert_eq!(r.document.nodes.len(), 1);
7581− }
7582−
7583− #[test]
7584− fn parses_page_directive() {
7585− let r = parse_ok("@page My Title\n");
7586− assert_eq!(
7587− r.document.page.map(|p| p.title).as_deref(),
7588− Some("My Title")
7589− );
7590− }
7591−
7592− #[test]
7593− fn let_variable_substitution() {
7594− let r = parse_ok("@let color red\n@text [color $color] hi\n");
7595− assert_eq!(
7596− r.document.variables.get("color").map(|s| s.as_str()),
7597− Some("red")
7598− );
7599− }
7600−
7601− #[test]
7602− fn error_recovery_continues_after_unknown_element() {
7603− // Intentionally malformed line followed by a valid one — recovery must
7604− // let us still see the good line in diagnostics / output.
7605− let r = parse("@notareal\n@text hi\n");
7606− let has_error = r.diagnostics.iter().any(|d| d.severity == Severity::Error);
7607− assert!(has_error, "expected at least one error for @notareal");
7608− }
7609−
7610− #[test]
7611− fn undefined_fn_is_reported_not_panics() {
7612− // Prior to the unwrap fix this panicked.
7613− let r = parse("@missing\n");
7614− assert!(r.diagnostics.iter().any(|d| d.severity == Severity::Error));
7615− }
7616−
7617− #[test]
7618− fn scope_without_selector_does_not_panic() {
7619− let r = parse("@scope\n body { background red; }\n");
7620− // Should parse — may or may not emit diagnostics, but must not panic.
7621− let _ = r;
7622− }
7623−
7624− #[test]
7625− fn levenshtein_bounded_respects_cutoff() {
7626− let a: Vec<char> = "hello".chars().collect();
7627− let b: Vec<char> = "world".chars().collect();
7628− // Full distance is 4, but asking for cutoff 2 should early-exit.
7629− let d = levenshtein_bounded(&a, &b, 2);
7630− assert!(d > 2, "expected early exit above cutoff, got {}", d);
7631− }
7632−
7633− #[test]
7634− fn severity_has_all_variants() {
7635− // This compiles only if Severity has Error, Warning, Info, Help.
7636− let all = [
7637− Severity::Error,
7638− Severity::Warning,
7639− Severity::Info,
7640− Severity::Help,
7641− ];
7642− assert_eq!(all.len(), 4);
7643− }
7644−
7645− #[test]
7646− fn arithmetic_empty_operator_does_not_panic() {
7647− // Guards the `op.trim().chars().next().unwrap()` fix.
7648− let r = parse("@let x = 1 + 2\n");
7649− assert_eq!(r.document.variables.get("x").map(|s| s.as_str()), Some("3"));
7650− }
7651−}