urbit/outside/commonmark/js/lib/blocks.js

699 lines
22 KiB
JavaScript

var C_GREATERTHAN = 62;
var C_SPACE = 32;
var C_OPEN_BRACKET = 91;
var InlineParser = require('./inlines');
var unescapeString = new InlineParser().unescapeString;
// Returns true if string contains only space characters.
var isBlank = function(s) {
return /^\s*$/.test(s);
};
// Convert tabs to spaces on each line using a 4-space tab stop.
var detabLine = function(text) {
if (text.indexOf('\t') == -1) {
return text;
} else {
var lastStop = 0;
return text.replace(/\t/g, function(match, offset) {
var result = ' '.slice((offset - lastStop) % 4);
lastStop = offset + 1;
return result;
});
}
};
// Attempt to match a regex in string s at offset offset.
// Return index of match or -1.
var matchAt = function(re, s, offset) {
var res = s.slice(offset).match(re);
if (res) {
return offset + res.index;
} else {
return -1;
}
};
var BLOCKTAGNAME = '(?:article|header|aside|hgroup|iframe|blockquote|hr|body|li|map|button|object|canvas|ol|caption|output|col|p|colgroup|pre|dd|progress|div|section|dl|table|td|dt|tbody|embed|textarea|fieldset|tfoot|figcaption|th|figure|thead|footer|footer|tr|form|ul|h1|h2|h3|h4|h5|h6|video|script|style)';
var HTMLBLOCKOPEN = "<(?:" + BLOCKTAGNAME + "[\\s/>]" + "|" +
"/" + BLOCKTAGNAME + "[\\s>]" + "|" + "[?!])";
var reHtmlBlockOpen = new RegExp('^' + HTMLBLOCKOPEN, 'i');
var reHrule = /^(?:(?:\* *){3,}|(?:_ *){3,}|(?:- *){3,}) *$/;
// DOC PARSER
// These are methods of a DocParser object, defined below.
var makeBlock = function(tag, start_line, start_column) {
return { t: tag,
open: true,
last_line_blank: false,
start_line: start_line,
start_column: start_column,
end_line: start_line,
children: [],
parent: null,
// string_content is formed by concatenating strings, in finalize:
string_content: "",
strings: [],
inline_content: []
};
};
// Returns true if parent block can contain child block.
var canContain = function(parent_type, child_type) {
return ( parent_type == 'Document' ||
parent_type == 'BlockQuote' ||
parent_type == 'ListItem' ||
(parent_type == 'List' && child_type == 'ListItem') );
};
// Returns true if block type can accept lines of text.
var acceptsLines = function(block_type) {
return ( block_type == 'Paragraph' ||
block_type == 'IndentedCode' ||
block_type == 'FencedCode' );
};
// Returns true if block ends with a blank line, descending if needed
// into lists and sublists.
var endsWithBlankLine = function(block) {
if (block.last_line_blank) {
return true;
}
if ((block.t == 'List' || block.t == 'ListItem') && block.children.length > 0) {
return endsWithBlankLine(block.children[block.children.length - 1]);
} else {
return false;
}
};
// Break out of all containing lists, resetting the tip of the
// document to the parent of the highest list, and finalizing
// all the lists. (This is used to implement the "two blank lines
// break of of all lists" feature.)
var breakOutOfLists = function(block, line_number) {
var b = block;
var last_list = null;
do {
if (b.t === 'List') {
last_list = b;
}
b = b.parent;
} while (b);
if (last_list) {
while (block != last_list) {
this.finalize(block, line_number);
block = block.parent;
}
this.finalize(last_list, line_number);
this.tip = last_list.parent;
}
};
// Add a line to the block at the tip. We assume the tip
// can accept lines -- that check should be done before calling this.
var addLine = function(ln, offset) {
var s = ln.slice(offset);
if (!(this.tip.open)) {
throw({ msg: "Attempted to add line (" + ln + ") to closed container." });
}
this.tip.strings.push(s);
};
// Add block of type tag as a child of the tip. If the tip can't
// accept children, close and finalize it and try its parent,
// and so on til we find a block that can accept children.
var addChild = function(tag, line_number, offset) {
while (!canContain(this.tip.t, tag)) {
this.finalize(this.tip, line_number);
}
var column_number = offset + 1; // offset 0 = column 1
var newBlock = makeBlock(tag, line_number, column_number);
this.tip.children.push(newBlock);
newBlock.parent = this.tip;
this.tip = newBlock;
return newBlock;
};
// Parse a list marker and return data on the marker (type,
// start, delimiter, bullet character, padding) or null.
var parseListMarker = function(ln, offset) {
var rest = ln.slice(offset);
var match;
var spaces_after_marker;
var data = {};
if (rest.match(reHrule)) {
return null;
}
if ((match = rest.match(/^[*+-]( +|$)/))) {
spaces_after_marker = match[1].length;
data.type = 'Bullet';
data.bullet_char = match[0][0];
} else if ((match = rest.match(/^(\d+)([.)])( +|$)/))) {
spaces_after_marker = match[3].length;
data.type = 'Ordered';
data.start = parseInt(match[1]);
data.delimiter = match[2];
} else {
return null;
}
var blank_item = match[0].length === rest.length;
if (spaces_after_marker >= 5 ||
spaces_after_marker < 1 ||
blank_item) {
data.padding = match[0].length - spaces_after_marker + 1;
} else {
data.padding = match[0].length;
}
return data;
};
// Returns true if the two list items are of the same type,
// with the same delimiter and bullet character. This is used
// in agglomerating list items into lists.
var listsMatch = function(list_data, item_data) {
return (list_data.type === item_data.type &&
list_data.delimiter === item_data.delimiter &&
list_data.bullet_char === item_data.bullet_char);
};
// Analyze a line of text and update the document appropriately.
// We parse markdown text by calling this on each line of input,
// then finalizing the document.
var incorporateLine = function(ln, line_number) {
var all_matched = true;
var last_child;
var first_nonspace;
var offset = 0;
var match;
var data;
var blank;
var indent;
var last_matched_container;
var i;
var CODE_INDENT = 4;
var container = this.doc;
var oldtip = this.tip;
// Convert tabs to spaces:
ln = detabLine(ln);
// For each containing block, try to parse the associated line start.
// Bail out on failure: container will point to the last matching block.
// Set all_matched to false if not all containers match.
while (container.children.length > 0) {
last_child = container.children[container.children.length - 1];
if (!last_child.open) {
break;
}
container = last_child;
match = matchAt(/[^ ]/, ln, offset);
if (match === -1) {
first_nonspace = ln.length;
blank = true;
} else {
first_nonspace = match;
blank = false;
}
indent = first_nonspace - offset;
switch (container.t) {
case 'BlockQuote':
if (indent <= 3 && ln.charCodeAt(first_nonspace) === C_GREATERTHAN) {
offset = first_nonspace + 1;
if (ln.charCodeAt(offset) === C_SPACE) {
offset++;
}
} else {
all_matched = false;
}
break;
case 'ListItem':
if (indent >= container.list_data.marker_offset +
container.list_data.padding) {
offset += container.list_data.marker_offset +
container.list_data.padding;
} else if (blank) {
offset = first_nonspace;
} else {
all_matched = false;
}
break;
case 'IndentedCode':
if (indent >= CODE_INDENT) {
offset += CODE_INDENT;
} else if (blank) {
offset = first_nonspace;
} else {
all_matched = false;
}
break;
case 'Header':
case 'HorizontalRule':
// a header can never container > 1 line, so fail to match:
all_matched = false;
if (blank) {
container.last_line_blank = true;
}
break;
case 'FencedCode':
// skip optional spaces of fence offset
i = container.fence_offset;
while (i > 0 && ln.charCodeAt(offset) === C_SPACE) {
offset++;
i--;
}
break;
case 'HtmlBlock':
if (blank) {
container.last_line_blank = true;
all_matched = false;
}
break;
case 'Paragraph':
if (blank) {
container.last_line_blank = true;
all_matched = false;
}
break;
default:
}
if (!all_matched) {
container = container.parent; // back up to last matching block
break;
}
}
last_matched_container = container;
// This function is used to finalize and close any unmatched
// blocks. We aren't ready to do this now, because we might
// have a lazy paragraph continuation, in which case we don't
// want to close unmatched blocks. So we store this closure for
// use later, when we have more information.
var closeUnmatchedBlocks = function(mythis) {
// finalize any blocks not matched
while (!already_done && oldtip != last_matched_container) {
mythis.finalize(oldtip, line_number);
oldtip = oldtip.parent;
}
var already_done = true;
};
// Check to see if we've hit 2nd blank line; if so break out of list:
if (blank && container.last_line_blank) {
this.breakOutOfLists(container, line_number);
}
// Unless last matched container is a code block, try new container starts,
// adding children to the last matched container:
while (container.t != 'FencedCode' &&
container.t != 'IndentedCode' &&
container.t != 'HtmlBlock' &&
// this is a little performance optimization:
matchAt(/^[ #`~*+_=<>0-9-]/,ln,offset) !== -1) {
match = matchAt(/[^ ]/, ln, offset);
if (match === -1) {
first_nonspace = ln.length;
blank = true;
} else {
first_nonspace = match;
blank = false;
}
indent = first_nonspace - offset;
if (indent >= CODE_INDENT) {
// indented code
if (this.tip.t != 'Paragraph' && !blank) {
offset += CODE_INDENT;
closeUnmatchedBlocks(this);
container = this.addChild('IndentedCode', line_number, offset);
} else { // indent > 4 in a lazy paragraph continuation
break;
}
} else if (ln.charCodeAt(first_nonspace) === C_GREATERTHAN) {
// blockquote
offset = first_nonspace + 1;
// optional following space
if (ln.charCodeAt(offset) === C_SPACE) {
offset++;
}
closeUnmatchedBlocks(this);
container = this.addChild('BlockQuote', line_number, offset);
} else if ((match = ln.slice(first_nonspace).match(/^#{1,6}(?: +|$)/))) {
// ATX header
offset = first_nonspace + match[0].length;
closeUnmatchedBlocks(this);
container = this.addChild('Header', line_number, first_nonspace);
container.level = match[0].trim().length; // number of #s
// remove trailing ###s:
container.strings =
[ln.slice(offset).replace(/^ *#+ *$/, '').replace(/ +#+ *$/,'')];
break;
} else if ((match = ln.slice(first_nonspace).match(/^`{3,}(?!.*`)|^~{3,}(?!.*~)/))) {
// fenced code block
var fence_length = match[0].length;
closeUnmatchedBlocks(this);
container = this.addChild('FencedCode', line_number, first_nonspace);
container.fence_length = fence_length;
container.fence_char = match[0][0];
container.fence_offset = first_nonspace - offset;
offset = first_nonspace + fence_length;
break;
} else if (matchAt(reHtmlBlockOpen, ln, first_nonspace) !== -1) {
// html block
closeUnmatchedBlocks(this);
container = this.addChild('HtmlBlock', line_number, first_nonspace);
// note, we don't adjust offset because the tag is part of the text
break;
} else if (container.t == 'Paragraph' &&
container.strings.length === 1 &&
((match = ln.slice(first_nonspace).match(/^(?:=+|-+) *$/)))) {
// setext header line
closeUnmatchedBlocks(this);
container.t = 'Header'; // convert Paragraph to SetextHeader
container.level = match[0][0] === '=' ? 1 : 2;
offset = ln.length;
} else if (matchAt(reHrule, ln, first_nonspace) !== -1) {
// hrule
closeUnmatchedBlocks(this);
container = this.addChild('HorizontalRule', line_number, first_nonspace);
offset = ln.length - 1;
break;
} else if ((data = parseListMarker(ln, first_nonspace))) {
// list item
closeUnmatchedBlocks(this);
data.marker_offset = indent;
offset = first_nonspace + data.padding;
// add the list if needed
if (container.t !== 'List' ||
!(listsMatch(container.list_data, data))) {
container = this.addChild('List', line_number, first_nonspace);
container.list_data = data;
}
// add the list item
container = this.addChild('ListItem', line_number, first_nonspace);
container.list_data = data;
} else {
break;
}
if (acceptsLines(container.t)) {
// if it's a line container, it can't contain other containers
break;
}
}
// What remains at the offset is a text line. Add the text to the
// appropriate container.
match = matchAt(/[^ ]/, ln, offset);
if (match === -1) {
first_nonspace = ln.length;
blank = true;
} else {
first_nonspace = match;
blank = false;
}
indent = first_nonspace - offset;
// First check for a lazy paragraph continuation:
if (this.tip !== last_matched_container &&
!blank &&
this.tip.t == 'Paragraph' &&
this.tip.strings.length > 0) {
// lazy paragraph continuation
this.last_line_blank = false;
this.addLine(ln, offset);
} else { // not a lazy continuation
// finalize any blocks not matched
closeUnmatchedBlocks(this);
// Block quote lines are never blank as they start with >
// and we don't count blanks in fenced code for purposes of tight/loose
// lists or breaking out of lists. We also don't set last_line_blank
// on an empty list item.
container.last_line_blank = blank &&
!(container.t == 'BlockQuote' ||
container.t == 'Header' ||
container.t == 'FencedCode' ||
(container.t == 'ListItem' &&
container.children.length === 0 &&
container.start_line == line_number));
var cont = container;
while (cont.parent) {
cont.parent.last_line_blank = false;
cont = cont.parent;
}
switch (container.t) {
case 'IndentedCode':
case 'HtmlBlock':
this.addLine(ln, offset);
break;
case 'FencedCode':
// check for closing code fence:
match = (indent <= 3 &&
ln.charAt(first_nonspace) == container.fence_char &&
ln.slice(first_nonspace).match(/^(?:`{3,}|~{3,})(?= *$)/));
if (match && match[0].length >= container.fence_length) {
// don't add closing fence to container; instead, close it:
this.finalize(container, line_number);
} else {
this.addLine(ln, offset);
}
break;
case 'Header':
case 'HorizontalRule':
// nothing to do; we already added the contents.
break;
default:
if (acceptsLines(container.t)) {
this.addLine(ln, first_nonspace);
} else if (blank) {
// do nothing
} else if (container.t != 'HorizontalRule' &&
container.t != 'Header') {
// create paragraph container for line
container = this.addChild('Paragraph', line_number, first_nonspace);
this.addLine(ln, first_nonspace);
} else {
console.log("Line " + line_number.toString() +
" with container type " + container.t +
" did not match any condition.");
}
}
}
};
// Finalize a block. Close it and do any necessary postprocessing,
// e.g. creating string_content from strings, setting the 'tight'
// or 'loose' status of a list, and parsing the beginnings
// of paragraphs for reference definitions. Reset the tip to the
// parent of the closed block.
var finalize = function(block, line_number) {
var pos;
// don't do anything if the block is already closed
if (!block.open) {
return 0;
}
block.open = false;
if (line_number > block.start_line) {
block.end_line = line_number - 1;
} else {
block.end_line = line_number;
}
switch (block.t) {
case 'Paragraph':
block.string_content = block.strings.join('\n').replace(/^ */m,'');
// delete block.strings;
// try parsing the beginning as link reference definitions:
while (block.string_content.charCodeAt(0) === C_OPEN_BRACKET &&
(pos = this.inlineParser.parseReference(block.string_content,
this.refmap))) {
block.string_content = block.string_content.slice(pos);
if (isBlank(block.string_content)) {
block.t = 'ReferenceDef';
break;
}
}
break;
case 'Header':
case 'HtmlBlock':
block.string_content = block.strings.join('\n');
break;
case 'IndentedCode':
block.string_content = block.strings.join('\n').replace(/(\n *)*$/,'\n');
block.t = 'CodeBlock';
break;
case 'FencedCode':
// first line becomes info string
block.info = unescapeString(block.strings[0].trim());
if (block.strings.length == 1) {
block.string_content = '';
} else {
block.string_content = block.strings.slice(1).join('\n') + '\n';
}
block.t = 'CodeBlock';
break;
case 'List':
block.tight = true; // tight by default
var numitems = block.children.length;
var i = 0;
while (i < numitems) {
var item = block.children[i];
// check for non-final list item ending with blank line:
var last_item = i == numitems - 1;
if (endsWithBlankLine(item) && !last_item) {
block.tight = false;
break;
}
// recurse into children of list item, to see if there are
// spaces between any of them:
var numsubitems = item.children.length;
var j = 0;
while (j < numsubitems) {
var subitem = item.children[j];
var last_subitem = j == numsubitems - 1;
if (endsWithBlankLine(subitem) && !(last_item && last_subitem)) {
block.tight = false;
break;
}
j++;
}
i++;
}
break;
default:
break;
}
this.tip = block.parent || this.top;
};
// Walk through a block & children recursively, parsing string content
// into inline content where appropriate. Returns new object.
var processInlines = function(block) {
var newblock = {};
newblock.t = block.t;
newblock.start_line = block.start_line;
newblock.start_column = block.start_column;
newblock.end_line = block.end_line;
switch(block.t) {
case 'Paragraph':
newblock.inline_content =
this.inlineParser.parse(block.string_content.trim(), this.refmap);
break;
case 'Header':
newblock.inline_content =
this.inlineParser.parse(block.string_content.trim(), this.refmap);
newblock.level = block.level;
break;
case 'List':
newblock.list_data = block.list_data;
newblock.tight = block.tight;
break;
case 'CodeBlock':
newblock.string_content = block.string_content;
newblock.info = block.info;
break;
case 'HtmlBlock':
newblock.string_content = block.string_content;
break;
default:
break;
}
if (block.children) {
var newchildren = [];
for (var i = 0; i < block.children.length; i++) {
newchildren.push(this.processInlines(block.children[i]));
}
newblock.children = newchildren;
}
return newblock;
};
// The main parsing function. Returns a parsed document AST.
var parse = function(input) {
this.doc = makeBlock('Document', 1, 1);
this.tip = this.doc;
this.refmap = {};
var lines = input.replace(/\n$/,'').split(/\r\n|\n|\r/);
var len = lines.length;
for (var i = 0; i < len; i++) {
this.incorporateLine(lines[i], i+1);
}
while (this.tip) {
this.finalize(this.tip, len - 1);
}
return this.processInlines(this.doc);
};
// The DocParser object.
function DocParser(){
return {
doc: makeBlock('Document', 1, 1),
tip: this.doc,
refmap: {},
inlineParser: new InlineParser(),
breakOutOfLists: breakOutOfLists,
addLine: addLine,
addChild: addChild,
incorporateLine: incorporateLine,
finalize: finalize,
processInlines: processInlines,
parse: parse
};
}
module.exports = DocParser;