- var Node = require('./node');
- 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) {
- "use strict";
- return /^\s*$/.test(s);
- };
- // Convert tabs to spaces on each line using a 4-space tab stop.
- var detabLine = function(text) {
- "use strict";
- if (text.indexOf('\0') !== -1) {
- // replace NUL for security
- text = text.replace(/\0/g, '\uFFFD');
- }
- if (text.indexOf('\t') === -1) {
- return text;
- } else {
- var lastStop = 0;
- return text.replace(/\t/g, function(match, offset) {
- var result = ' '.slice((offset - lastStop) % 4);
- lastStop = offset + 1;
- return result;
- });
- }
- };
- // Attempt to match a regex in string s at offset offset.
- // Return index of match or -1.
- var matchAt = function(re, s, offset) {
- "use strict";
- var res = s.slice(offset).match(re);
- if (res) {
- return offset + res.index;
- } else {
- return -1;
- }
- };
- var BLOCKTAGNAME = '(?:article|header|aside|hgroup|iframe|blockquote|hr|body|li|map|button|object|canvas|ol|caption|output|col|p|colgroup|pre|dd|progress|div|section|dl|table|td|dt|tbody|embed|textarea|fieldset|tfoot|figcaption|th|figure|thead|footer|footer|tr|form|ul|h1|h2|h3|h4|h5|h6|video|script|style)';
- var HTMLBLOCKOPEN = "<(?:" + BLOCKTAGNAME + "[\\s/>]" + "|" +
- "/" + BLOCKTAGNAME + "[\\s>]" + "|" + "[?!])";
- var reHtmlBlockOpen = new RegExp('^' + HTMLBLOCKOPEN, 'i');
- var reHrule = /^(?:(?:\* *){3,}|(?:_ *){3,}|(?:- *){3,}) *$/;
- // DOC PARSER
- // These are methods of a DocParser object, defined below.
- // Returns true if parent block can contain child block.
- var canContain = function(parent_type, child_type) {
- "use strict";
- 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) {
- "use strict";
- 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) {
- "use strict";
- while (block) {
- if (block.last_line_blank) {
- return true;
- }
- if (block.t === 'List' || block.t === 'ListItem') {
- block = block.lastChild;
- } else {
- break;
- }
- }
- 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) {
- "use strict";
- 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) {
- "use strict";
- 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) {
- "use strict";
- while (!canContain(this.tip.t, tag)) {
- this.finalize(this.tip, line_number - 1);
- }
- var column_number = offset + 1; // offset 0 = column 1
- var newBlock = new Node(tag, { start: [line_number, column_number],
- end: [0, 0] });
- newBlock.strings = [];
- newBlock.string_content = undefined;
- this.tip.appendChild(newBlock);
- 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) {
- "use strict";
- var rest = ln.slice(offset);
- var match;
- var spaces_after_marker;
- var data = { type: undefined,
- tight: true,
- bullet_char: undefined,
- start: undefined,
- delimiter: undefined,
- padding: undefined };
- 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) {
- "use strict";
- 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) {
- "use strict";
- var all_matched = true;
- 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.lastChild) {
- if (!container.lastChild.open) {
- break;
- }
- container = container.lastChild;
- 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) {
- var already_done = false;
- // finalize any blocks not matched
- while (!already_done && oldtip !== last_matched_container) {
- mythis.finalize(oldtip, line_number - 1);
- oldtip = oldtip.parent;
- }
- 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.firstChild &&
- container.pos.start[0] === 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) {
- break;
- } 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.");
- }
- }
- }
- this.lastLineLength = ln.length - 1; // -1 for newline
- };
- // 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) {
- "use strict";
- var pos;
- // don't do anything if the block is already closed
- if (!block.open) {
- return 0;
- }
- block.open = false;
- block.pos.end = [line_number, this.lastLineLength + 1];
- switch (block.t) {
- case 'Paragraph':
- block.string_content = block.strings.join('\n').replace(/^ {2,}/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':
- block.string_content = block.strings.join('\n');
- break;
- case 'HtmlBlock':
- block.c = block.strings.join('\n');
- break;
- case 'IndentedCode':
- block.c = 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.c = '';
- } else {
- block.c = block.strings.slice(1).join('\n') + '\n';
- }
- block.t = 'CodeBlock';
- break;
- case 'List':
- block.list_data.tight = true; // tight by default
- var item = block.firstChild;
- while (item) {
- // check for non-final list item ending with blank line:
- if (endsWithBlankLine(item) && item.next) {
- block.list_data.tight = false;
- break;
- }
- // recurse into children of list item, to see if there are
- // spaces between any of them:
- var subitem = item.firstChild;
- while (subitem) {
- if (endsWithBlankLine(subitem) && (item.next || subitem.next)) {
- block.list_data.tight = false;
- break;
- }
- subitem = subitem.next;
- }
- item = item.next;
- }
- 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) {
- "use strict";
- var node, event;
- var walker = block.walker();
- while ((event = walker.next())) {
- node = event.node;
- if (!event.entering && (node.t === 'Paragraph' ||
- node.t === 'Header')) {
- this.inlineParser.parse(node, this.refmap);
- }
- }
- };
- var Document = function() {
- var doc = new Node('Document', { start: [1, 1], end: [0, 0] });
- doc.string_content = undefined;
- doc.strings = [];
- return doc;
- };
- // The main parsing function. Returns a parsed document AST.
- var parse = function(input) {
- "use strict";
- this.doc = Document();
- 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);
- }
- this.processInlines(this.doc);
- return this.doc;
- };
- // The DocParser object.
- function DocParser(){
- "use strict";
- return {
- doc: Document(),
- tip: this.doc,
- refmap: {},
- lastLineLength: 0,
- inlineParser: new InlineParser(),
- breakOutOfLists: breakOutOfLists,
- addLine: addLine,
- addChild: addChild,
- incorporateLine: incorporateLine,
- finalize: finalize,
- processInlines: processInlines,
- parse: parse
- };
- }
- module.exports = DocParser;
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