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1 // Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file | |
2 // for details. All rights reserved. Use of this source code is governed by a | |
3 // BSD-style license that can be found in the LICENSE file. | |
4 | |
5 /// Parses text in a markdown-like format and renders to HTML. | |
6 #library('markdown'); | |
7 | |
8 #source('ast.dart'); | |
9 #source('block_parser.dart'); | |
10 #source('html_renderer.dart'); | |
11 #source('inline_parser.dart'); | |
12 | |
13 /// Converts the given string of markdown to HTML. | |
14 String markdownToHtml(String markdown) { | |
15 final document = new Document(); | |
16 | |
17 final lines = markdown.split('\n'); | |
18 document.parseRefLinks(lines); | |
19 final blocks = document.parseLines(lines); | |
20 return renderToHtml(blocks); | |
21 } | |
22 | |
23 /// Replaces `<`, `&`, and `>`, with their HTML entity equivalents. | |
24 String escapeHtml(String html) { | |
25 return html.replaceAll('&', '&') | |
26 .replaceAll('<', '<') | |
27 .replaceAll('>', '>'); | |
28 } | |
29 | |
30 var _implicitLinkResolver; | |
31 | |
32 Node setImplicitLinkResolver(Node resolver(String text)) { | |
33 _implicitLinkResolver = resolver; | |
34 } | |
35 | |
36 /// Maintains the context needed to parse a markdown document. | |
37 class Document { | |
38 final Map<String, Link> refLinks; | |
39 | |
40 Document() | |
41 : refLinks = <String, Link>{}; | |
42 | |
43 parseRefLinks(List<String> lines) { | |
44 // This is a hideous regex. It matches: | |
45 // [id]: http:foo.com "some title" | |
46 // Where there may whitespace in there, and where the title may be in | |
47 // single quotes, double quotes, or parentheses. | |
48 final indent = @'^[ ]{0,3}'; // Leading indentation. | |
49 final id = @'\[([^\]]+)\]'; // Reference id in [brackets]. | |
50 final quote = @'"[^"]+"'; // Title in "double quotes". | |
51 final apos = @"'[^']+'"; // Title in 'single quotes'. | |
52 final paren = @"\([^)]+\)"; // Title in (parentheses). | |
53 final pattern = new RegExp( | |
54 '$indent$id:\\s+(\\S+)\\s*($quote|$apos|$paren|)\\s*\$'); | |
55 | |
56 for (int i = 0; i < lines.length; i++) { | |
57 final match = pattern.firstMatch(lines[i]); | |
58 if (match != null) { | |
59 // Parse the link. | |
60 var id = match[1]; | |
61 var url = match[2]; | |
62 var title = match[3]; | |
63 | |
64 if (title == '') { | |
65 // No title. | |
66 title = null; | |
67 } else { | |
68 // Remove "", '', or (). | |
69 title = title.substring(1, title.length - 1); | |
70 } | |
71 | |
72 // References are case-insensitive. | |
73 id = id.toLowerCase(); | |
74 | |
75 refLinks[id] = new Link(id, url, title); | |
76 | |
77 // Remove it from the output. We replace it with a blank line which will | |
78 // get consumed by later processing. | |
79 lines[i] = ''; | |
80 } | |
81 } | |
82 } | |
83 | |
84 /// Parse the given [lines] of markdown to a series of AST nodes. | |
85 List<Node> parseLines(List<String> lines) { | |
86 final parser = new BlockParser(lines, this); | |
87 | |
88 final blocks = []; | |
89 while (!parser.isDone) { | |
90 for (final syntax in BlockSyntax.syntaxes) { | |
91 if (syntax.canParse(parser)) { | |
92 final block = syntax.parse(parser); | |
93 if (block != null) blocks.add(block); | |
94 break; | |
95 } | |
96 } | |
97 } | |
98 | |
99 return blocks; | |
100 } | |
101 | |
102 /// Takes a string of raw text and processes all inline markdown tags, | |
103 /// returning a list of AST nodes. For example, given ``"*this **is** a* | |
104 /// `markdown`"``, returns: | |
105 /// `<em>this <strong>is</strong> a</em> <code>markdown</code>`. | |
106 List<Node> parseInline(String text) => new InlineParser(text, this).parse(); | |
107 } | |
108 | |
109 class Link { | |
110 final String id; | |
111 final String url; | |
112 final String title; | |
113 Link(this.id, this.url, this.title); | |
114 } | |
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