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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 // TODO(rnystrom): Use "package:" URL (#4968). | |
9 part 'src/markdown/ast.dart'; | |
10 part 'src/markdown/block_parser.dart'; | |
11 part 'src/markdown/html_renderer.dart'; | |
12 part 'src/markdown/inline_parser.dart'; | |
13 | |
14 typedef Node Resolver(String name); | |
15 | |
16 /// Converts the given string of markdown to HTML. | |
17 String markdownToHtml(String markdown, {inlineSyntaxes, linkResolver}) { | |
18 final document = new Document(inlineSyntaxes: inlineSyntaxes, | |
19 linkResolver: linkResolver); | |
20 | |
21 // Replace windows line endings with unix line endings, and split. | |
22 final lines = markdown.replaceAll('\r\n','\n').split('\n'); | |
23 document.parseRefLinks(lines); | |
24 final blocks = document.parseLines(lines); | |
25 return renderToHtml(blocks); | |
26 } | |
27 | |
28 /// Replaces `<`, `&`, and `>`, with their HTML entity equivalents. | |
29 String escapeHtml(String html) { | |
30 return html.replaceAll('&', '&') | |
31 .replaceAll('<', '<') | |
32 .replaceAll('>', '>'); | |
33 } | |
34 | |
35 /// Maintains the context needed to parse a markdown document. | |
36 class Document { | |
37 final Map<String, Link> refLinks; | |
38 List<InlineSyntax> inlineSyntaxes; | |
39 Resolver linkResolver; | |
40 | |
41 Document({this.inlineSyntaxes, this.linkResolver}) | |
42 : refLinks = <String, Link>{}; | |
43 | |
44 parseRefLinks(List<String> lines) { | |
45 // This is a hideous regex. It matches: | |
46 // [id]: http:foo.com "some title" | |
47 // Where there may whitespace in there, and where the title may be in | |
48 // single quotes, double quotes, or parentheses. | |
49 final indent = r'^[ ]{0,3}'; // Leading indentation. | |
50 final id = r'\[([^\]]+)\]'; // Reference id in [brackets]. | |
51 final quote = r'"[^"]+"'; // Title in "double quotes". | |
52 final apos = r"'[^']+'"; // Title in 'single quotes'. | |
53 final paren = r"\([^)]+\)"; // Title in (parentheses). | |
54 final pattern = new RegExp( | |
55 '$indent$id:\\s+(\\S+)\\s*($quote|$apos|$paren|)\\s*\$'); | |
56 | |
57 for (int i = 0; i < lines.length; i++) { | |
58 final match = pattern.firstMatch(lines[i]); | |
59 if (match != null) { | |
60 // Parse the link. | |
61 var id = match[1]; | |
62 var url = match[2]; | |
63 var title = match[3]; | |
64 | |
65 if (title == '') { | |
66 // No title. | |
67 title = null; | |
68 } else { | |
69 // Remove "", '', or (). | |
70 title = title.substring(1, title.length - 1); | |
71 } | |
72 | |
73 // References are case-insensitive. | |
74 id = id.toLowerCase(); | |
75 | |
76 refLinks[id] = new Link(id, url, title); | |
77 | |
78 // Remove it from the output. We replace it with a blank line which will | |
79 // get consumed by later processing. | |
80 lines[i] = ''; | |
81 } | |
82 } | |
83 } | |
84 | |
85 /// Parse the given [lines] of markdown to a series of AST nodes. | |
86 List<Node> parseLines(List<String> lines) { | |
87 final parser = new BlockParser(lines, this); | |
88 | |
89 final blocks = []; | |
90 while (!parser.isDone) { | |
91 for (final syntax in BlockSyntax.syntaxes) { | |
92 if (syntax.canParse(parser)) { | |
93 final block = syntax.parse(parser); | |
94 if (block != null) blocks.add(block); | |
95 break; | |
96 } | |
97 } | |
98 } | |
99 | |
100 return blocks; | |
101 } | |
102 | |
103 /// Takes a string of raw text and processes all inline markdown tags, | |
104 /// returning a list of AST nodes. For example, given ``"*this **is** a* | |
105 /// `markdown`"``, returns: | |
106 /// `<em>this <strong>is</strong> a</em> <code>markdown</code>`. | |
107 List<Node> parseInline(String text) => new InlineParser(text, this).parse(); | |
108 } | |
109 | |
110 class Link { | |
111 final String id; | |
112 final String url; | |
113 final String title; | |
114 Link(this.id, this.url, this.title); | |
115 } | |
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