add example

Cargo.lock

@@ -93,6 +93,16 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "codespan-reporting"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3538270d33cc669650c4b093848450d380def10c331d38c768e34cac80576e6e"
+dependencies = [
+ "termcolor",
+ "unicode-width",
+]
+
 [[package]]
 name = "console"
 version = "0.14.1"
@@ -177,6 +187,7 @@ checksum = "a357d28ed41a50f9c765dbfe56cbc04a64e53e5fc58ba79fbc34c10ef3df831f"
 name = "eww_config"
 version = "0.1.0"
 dependencies = [
+ "codespan-reporting",
  "insta",
  "itertools",
  "lalrpop",
@@ -525,6 +536,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2dfed899f0eb03f32ee8c6a0aabdb8a7949659e3466561fc0adf54e26d88c5f4"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "terminal_size"
 version = "0.1.17"
@@ -564,6 +584,12 @@ dependencies = [
  "crunchy",
 ]
 
+[[package]]
+name = "unicode-width"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
+
 [[package]]
 name = "unicode-xid"
 version = "0.2.2"
@@ -598,6 +624,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
 [[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"

Cargo.toml

@@ -14,6 +14,7 @@ regex = "1"
 itertools = "0.10"
 thiserror = "1.0"
 maplit = "1.0"
+codespan-reporting = "0.11"
 
 [build-dependencies]
 lalrpop = "0.19.5"

examples/errors.rs

@@ -0,0 +1,18 @@
+use eww_config::{config::*, error, expr::*, parser};
+
+fn main() {
+    let parser = parser::ExprParser::new();
+    let mut files = codespan_reporting::files::SimpleFiles::new();
+
+    let input = "(12 :bar 22 (foo) (baz))";
+
+    let file_id = files.add("foo.eww", input);
+    let ast = parser.parse(file_id, input).unwrap();
+    let element: Result<Element<Expr, Expr>, _> = Element::from_expr(ast);
+    let err = element.unwrap_err();
+
+    let diag = err.pretty_diagnostic(&files);
+    use codespan_reporting::term;
+    let mut writer = term::termcolor::StandardStream::stderr(term::termcolor::ColorChoice::Always);
+    term::emit(&mut writer, &term::Config::default(), &files, &diag).unwrap();
+}

src/config.rs

@@ -10,8 +10,6 @@ use std::{
     str::FromStr,
 };
 
-// https://michael-f-bryan.github.io/static-analyser-in-rust/book/codemap.html
-
 type VarName = String;
 type AttrValue = String;
 type AttrName = String;
@@ -59,7 +57,7 @@ mod test {
         let parser = parser::ExprParser::new();
         insta::with_settings!({sort_maps => true}, {
             insta::assert_debug_snapshot!(
-                Element::<Expr, Expr>::from_expr(parser.parse("(box :bar 12 :baz \"hi\" foo (bar))").unwrap()).unwrap()
+                Element::<Expr, Expr>::from_expr(parser.parse(0, "(box :bar 12 :baz \"hi\" foo (bar))").unwrap()).unwrap()
             );
         });
     }

src/error.rs

@@ -1,4 +1,5 @@
 use crate::expr::{Expr, ExprType, Span};
+use codespan_reporting::{diagnostic, files};
 use thiserror::Error;
 
 pub type AstResult<T> = Result<T, AstError>;
@@ -13,6 +14,17 @@ pub enum AstError {
     WrongExprType(Option<Span>, ExprType, ExprType),
 }
 
+impl AstError {
+    pub fn pretty_diagnostic(&self, files: &files::SimpleFiles<&str, &str>) -> diagnostic::Diagnostic<usize> {
+        let diag = diagnostic::Diagnostic::error().with_message(format!("{}", self));
+        if let AstError::WrongExprType(Some(span), ..) = self {
+            diag.with_labels(vec![diagnostic::Label::primary(span.2, span.0..span.1)])
+        } else {
+            diag
+        }
+    }
+}
+
 pub fn spanned(span: Span, err: impl Into<AstError>) -> AstError {
     use AstError::*;
     match err.into() {

src/expr.rs

@@ -5,7 +5,7 @@ use crate::{config::FromExpr, error::*};
 use std::fmt::Display;
 
 #[derive(Eq, PartialEq, Clone, Copy)]
-pub struct Span(pub usize, pub usize);
+pub struct Span(pub usize, pub usize, pub usize);
 
 impl std::fmt::Display for Span {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {

src/lib.rs

@@ -2,9 +2,9 @@
 #![allow(unused)]
 #![feature(try_blocks)]
 
-mod config;
+pub mod config;
-mod error;
+pub mod error;
-mod expr;
+pub mod expr;
 use error::AstError;
 
 use std::{fmt::Display, ops::Deref};
@@ -17,7 +17,7 @@ lalrpop_mod!(pub parser);
 
 macro_rules! test_parser {
     ($p:expr, $($text:literal),*) => {{
-        $(insta::assert_debug_snapshot!($p.parse($text));)*
+        $(insta::assert_debug_snapshot!($p.parse(0, $text));)*
     }}
 }
 

src/parser.lalrpop

@@ -2,23 +2,23 @@ use std::str::FromStr;
 //use crate::lexer;
 use crate::expr::{Expr, Span};
 
-grammar;
+grammar(file_id: usize);
 
 
 pub Expr: Expr = {
-    <l:@L> "(" <elems:(<Expr>)+> ")" <r:@R> => Expr::List(Span(l, r), elems),
+    <l:@L> "(" <elems:(<Expr>)+> ")" <r:@R> => Expr::List(Span(l, r, file_id), elems),
 
-    <l:@L> "{" <elems:(<(<Expr>)> <(<Expr>)>)*> "}" <r:@R> => Expr::Table(Span(l, r), elems),
+    <l:@L> "{" <elems:(<(<Expr>)> <(<Expr>)>)*> "}" <r:@R> => Expr::Table(Span(l, r, file_id), elems),
 
     <x:Keyword> => x,
     <x:Symbol> => x,
-    <l:@L> <x:StrLit> <r:@R> => Expr::Str(Span(l, r), x),
+    <l:@L> <x:StrLit> <r:@R> => Expr::Str(Span(l, r, file_id), x),
-    <l:@L> <x:Num> <r:@R> => Expr::Number(Span(l, r), x),
+    <l:@L> <x:Num> <r:@R> => Expr::Number(Span(l, r, file_id), x),
-    <l:@L> Comment <r:@R> => Expr::Comment(Span(l, r)),
+    <l:@L> Comment <r:@R> => Expr::Comment(Span(l, r, file_id)),
 };
 
-Keyword: Expr = <l:@L> <x:r":[^\s]+"> <r:@R> => Expr::Keyword(Span(l, r), x.to_string());
+Keyword: Expr = <l:@L> <x:r":[^\s]+"> <r:@R> => Expr::Keyword(Span(l, r, file_id), x.to_string());
-Symbol: Expr = <l:@L> <x:r"[a-zA-Z_!\?<>/.*-+][^\s{}\(\)]*"> <r:@R> => Expr::Symbol(Span(l, r), x.to_string());
+Symbol: Expr = <l:@L> <x:r"[a-zA-Z_!\?<>/.*-+][^\s{}\(\)]*"> <r:@R> => Expr::Symbol(Span(l, r, file_id), x.to_string());
 
 StrLit: String = {
     <x:r#""(?:[^"\\]|\\.)*""#> => {