GFM autolink extension (#203)
Add support for GFM autolink extension
diff --git a/lib/src/extension_set.dart b/lib/src/extension_set.dart
index bab57e5..d6bec74 100644
--- a/lib/src/extension_set.dart
+++ b/lib/src/extension_set.dart
@@ -40,6 +40,7 @@
new InlineHtmlSyntax(),
new StrikethroughSyntax(),
new EmojiSyntax(),
+ new AutolinkExtensionSyntax(),
]);
/// The [gitHubFlavored] extension set is close to compliance with the [GitHub
@@ -52,6 +53,7 @@
], [
new InlineHtmlSyntax(),
new StrikethroughSyntax(),
+ new AutolinkExtensionSyntax(),
]);
/// The deprecated name for the [gitHubFlavored] extension set.
diff --git a/lib/src/inline_parser.dart b/lib/src/inline_parser.dart
index 777ba21..12d8fee 100644
--- a/lib/src/inline_parser.dart
+++ b/lib/src/inline_parser.dart
@@ -68,9 +68,9 @@
// character position.
if (documentHasCustomInlineSyntaxes) {
// We should be less aggressive in blowing past "words".
- syntaxes.add(new TextSyntax(r'[A-Za-z0-9]+\b'));
+ syntaxes.add(new TextSyntax(r'[A-Za-z0-9]+(?=\s)'));
} else {
- syntaxes.add(new TextSyntax(r'[ \tA-Za-z0-9]*[A-Za-z0-9]'));
+ syntaxes.add(new TextSyntax(r'[ \tA-Za-z0-9]*[A-Za-z0-9](?=\s)'));
}
syntaxes.addAll(_defaultSyntaxes);
@@ -163,18 +163,19 @@
/// Tries to match at the parser's current position.
///
+ /// The parser's position can be overriden with [startMatchPos].
/// Returns whether or not the pattern successfully matched.
- bool tryMatch(InlineParser parser) {
- var startMatch = pattern.matchAsPrefix(parser.source, parser.pos);
- if (startMatch != null) {
- // Write any existing plain text up to this point.
- parser.writeText();
+ bool tryMatch(InlineParser parser, [int startMatchPos]) {
+ if (startMatchPos == null) startMatchPos = parser.pos;
- if (onMatch(parser, startMatch)) parser.consume(startMatch[0].length);
- return true;
- }
+ final startMatch = pattern.matchAsPrefix(parser.source, startMatchPos);
+ if (startMatch == null) return false;
- return false;
+ // Write any existing plain text up to this point.
+ parser.writeText();
+
+ if (onMatch(parser, startMatch)) parser.consume(startMatch[0].length);
+ return true;
}
/// Processes [match], adding nodes to [parser] and possibly advancing
@@ -274,6 +275,128 @@
}
}
+/// Matches autolinks like `http://foo.com`.
+class AutolinkExtensionSyntax extends InlineSyntax {
+ /// Broken up parts of the autolink regex for reusability and readability
+
+ // Autolinks can only come at the beginning of a line, after whitespace, or
+ // any of the delimiting characters *, _, ~, and (.
+ static const start = r'(?:^|[\s*_~(>])';
+ // An extended url autolink will be recognized when one of the schemes
+ // http://, https://, or ftp://, followed by a valid domain
+ static const scheme = r'(?:(?:https?|ftp):\/\/|www\.)';
+ // A valid domain consists of alphanumeric characters, underscores (_),
+ // hyphens (-) and periods (.). There must be at least one period, and no
+ // underscores may be present in the last two segments of the domain.
+ static const domainPart = r'\w\-';
+ static const domain = '[$domainPart][$domainPart.]+';
+ // A valid domain consists of alphanumeric characters, underscores (_),
+ // hyphens (-) and periods (.).
+ static const path = r'[^\s<]*';
+ // Trailing punctuation (specifically, ?, !, ., ,, :, *, _, and ~) will not
+ // be considered part of the autolink
+ static const truncatingPunctuationPositive = r'[?!.,:*_~]';
+
+ static final regExpTrailingPunc =
+ new RegExp('$truncatingPunctuationPositive*' + r'$');
+ static final regExpEndsWithColon = new RegExp(r'\&[a-zA-Z0-9]+;$');
+ static final regExpWhiteSpace = new RegExp(r'\s');
+
+ AutolinkExtensionSyntax() : super('$start(($scheme)($domain)($path))');
+
+ @override
+ bool tryMatch(InlineParser parser, [int startMatchPos]) {
+ return super.tryMatch(parser, parser.pos > 0 ? parser.pos - 1 : 0);
+ }
+
+ @override
+ bool onMatch(InlineParser parser, Match match) {
+ var url = match[1];
+ var href = url;
+ var matchLength = url.length;
+
+ if (url[0] == '>' || url.startsWith(regExpWhiteSpace)) {
+ url = url.substring(1, url.length - 1);
+ href = href.substring(1, href.length - 1);
+ parser.pos++;
+ matchLength--;
+ }
+
+ // Prevent accidental standard autolink matches
+ if (url.endsWith('>') && parser.source[parser.pos - 1] == '<') {
+ return false;
+ }
+
+ // When an autolink ends in ), we scan the entire autolink for the total
+ // number of parentheses. If there is a greater number of closing
+ // parentheses than opening ones, we don’t consider the last character
+ // part of the autolink, in order to facilitate including an autolink
+ // inside a parenthesis:
+ // https://github.github.com/gfm/#example-600
+ if (url.endsWith(')')) {
+ final opening = _countChars(url, '(');
+ final closing = _countChars(url, ')');
+
+ if (closing > opening) {
+ url = url.substring(0, url.length - 1);
+ href = href.substring(0, href.length - 1);
+ matchLength--;
+ }
+ }
+
+ // Trailing punctuation (specifically, ?, !, ., ,, :, *, _, and ~) will
+ // not be considered part of the autolink, though they may be included
+ // in the interior of the link:
+ // https://github.github.com/gfm/#example-599
+ final trailingPunc = regExpTrailingPunc.firstMatch(url);
+ if (trailingPunc != null) {
+ url = url.substring(0, url.length - trailingPunc[0].length);
+ href = href.substring(0, href.length - trailingPunc[0].length);
+ matchLength -= trailingPunc[0].length;
+ }
+
+ // If an autolink ends in a semicolon (;), we check to see if it appears
+ // to resemble an
+ // [entity reference](https://github.github.com/gfm/#entity-references);
+ // if the preceding text is & followed by one or more alphanumeric
+ // characters. If so, it is excluded from the autolink:
+ // https://github.github.com/gfm/#example-602
+ if (url.endsWith(';')) {
+ final entityRef = regExpEndsWithColon.firstMatch(url);
+ if (entityRef != null) {
+ // Strip out HTML entity reference
+ url = url.substring(0, url.length - entityRef[0].length);
+ href = href.substring(0, href.length - entityRef[0].length);
+ matchLength -= entityRef[0].length;
+ }
+ }
+
+ // The scheme http will be inserted automatically
+ if (!href.startsWith('http://') &&
+ !href.startsWith('https://') &&
+ !href.startsWith('ftp://')) {
+ href = 'http://$href';
+ }
+
+ final anchor = new Element.text('a', escapeHtml(url));
+ anchor.attributes['href'] = Uri.encodeFull(href);
+ parser.addNode(anchor);
+
+ parser.consume(matchLength);
+ return false;
+ }
+
+ int _countChars(String input, String char) {
+ var count = 0;
+
+ for (var i = 0; i < input.length; i++) {
+ if (input[i] == char) count++;
+ }
+
+ return count;
+ }
+}
+
class _DelimiterRun {
static final String punctuation = r'''!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~''';
// TODO(srawlins): Unicode whitespace
@@ -608,7 +731,7 @@
CodeSyntax() : super(_pattern);
- bool tryMatch(InlineParser parser) {
+ bool tryMatch(InlineParser parser, [int startMatchPos]) {
if (parser.pos > 0 && parser.source[parser.pos - 1] == '`') {
// Not really a match! We can't just sneak past one backtick to try the
// next character. An example of this situation would be:
diff --git a/tool/gfm_stats.json b/tool/gfm_stats.json
index e1f9f43..88d8819 100644
--- a/tool/gfm_stats.json
+++ b/tool/gfm_stats.json
@@ -34,21 +34,21 @@
"589": "strict",
"590": "loose",
"591": "loose",
- "592": "loose",
+ "592": "fail",
"593": "loose",
"594": "loose",
- "595": "strict",
+ "595": "fail",
"596": "strict"
},
"Autolinks (extension)": {
- "597": "fail",
- "598": "fail",
- "599": "fail",
- "600": "fail",
- "601": "fail",
- "602": "fail",
- "603": "fail",
- "604": "fail",
+ "597": "strict",
+ "598": "strict",
+ "599": "strict",
+ "600": "loose",
+ "601": "strict",
+ "602": "loose",
+ "603": "strict",
+ "604": "strict",
"605": "fail",
"606": "fail",
"607": "fail"
diff --git a/tool/gfm_stats.txt b/tool/gfm_stats.txt
index 68fd77e..11b8b83 100644
--- a/tool/gfm_stats.txt
+++ b/tool/gfm_stats.txt
@@ -1,6 +1,6 @@
17 of 18 – 94.4% ATX headings
- 19 of 19 – 100.0% Autolinks
- 0 of 11 – 0.0% Autolinks (extension)
+ 17 of 19 – 89.5% Autolinks
+ 8 of 11 – 72.7% Autolinks (extension)
9 of 13 – 69.2% Backslash escapes
1 of 1 – 100.0% Blank lines
22 of 25 – 88.0% Block quotes
@@ -28,4 +28,4 @@
11 of 11 – 100.0% Tabs
3 of 3 – 100.0% Textual content
19 of 19 – 100.0% Thematic breaks
- 571 of 647 – 88.3% TOTAL
+ 577 of 647 – 89.2% TOTAL
