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); } var column_number = offset + 1; // offset 0 = column 1 var newBlock = new Node(tag, { start: [line_number, column_number], end: [] }); 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 = {}; 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); 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."); } } } }; // 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; if (line_number > block.pos.start[0]) { block.pos.end = [line_number - 1]; // TODO end column } else { block.pos.end = [line_number]; } 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': 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 item = block.firstChild; while (item) { // check for non-final list item ending with blank line: if (endsWithBlankLine(item) && item.next) { block.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.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); } } }; // The main parsing function. Returns a parsed document AST. var parse = function(input) { "use strict"; this.doc = new Node('Document', { start: [1, 1], end: [] }); 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); } this.processInlines(this.doc); return this.doc; }; // The DocParser object. function DocParser(){ "use strict"; return { doc: new Node('Document', { start: [1, 1], end: [] }), tip: this.doc, refmap: {}, inlineParser: new InlineParser(), breakOutOfLists: breakOutOfLists, addLine: addLine, addChild: addChild, incorporateLine: incorporateLine, finalize: finalize, processInlines: processInlines, parse: parse }; } module.exports = DocParser;