Clean up:

lib/src/document.dart

-library markdown.document;
+library markdown.src.document;
 
 import 'ast.dart';
 import 'block_parser.dart';
 import 'inline_parser.dart';
 
 /// Maintains the context needed to parse a markdown document.
 class Document {
   final Map<String, Link> refLinks;
   List<InlineSyntax> inlineSyntaxes;
   Resolver linkResolver;
   Resolver imageLinkResolver;
 
   Document({this.inlineSyntaxes, this.linkResolver, this.imageLinkResolver})
       : refLinks = <String, Link>{};
 
   parseRefLinks(List<String> lines) {
     // This is a hideous regex. It matches:
     // [id]: http:foo.com "some title"
     // Where there may whitespace in there, and where the title may be in
     // single quotes, double quotes, or parentheses.
-    final indent = r'^[ ]{0,3}'; // Leading indentation.
-    final id = r'\[([^\]]+)\]'; // Reference id in [brackets].
-    final quote = r'"[^"]+"'; // Title in "double quotes".
-    final apos = r"'[^']+'"; // Title in 'single quotes'.
-    final paren = r"\([^)]+\)"; // Title in (parentheses).
-    final pattern = new RegExp(
-        '$indent$id:\\s+(\\S+)\\s*($quote|$apos|$paren|)\\s*\$');
+    var indent = r'^[ ]{0,3}'; // Leading indentation.
+    var id = r'\[([^\]]+)\]'; // Reference id in [brackets].
+    var quote = r'"[^"]+"'; // Title in "double quotes".
+    var apos = r"'[^']+'"; // Title in 'single quotes'.
+    var paren = r"\([^)]+\)"; // Title in (parentheses).
+    var pattern =
+        new RegExp('$indent$id:\\s+(\\S+)\\s*($quote|$apos|$paren|)\\s*\$');
 
-    for (int i = 0; i < lines.length; i++) {
-      final match = pattern.firstMatch(lines[i]);
+    for (var i = 0; i < lines.length; i++) {
+      var match = pattern.firstMatch(lines[i]);
       if (match != null) {
         // Parse the link.
         var id = match[1];
         var url = match[2];
         var title = match[3];
 
         if (title == '') {
           // No title.
           title = null;
         } else {
           // Remove "", '', or ().
           title = title.substring(1, title.length - 1);
         }
 
         // References are case-insensitive.
         id = id.toLowerCase();
 
         refLinks[id] = new Link(id, url, title);
 
         // Remove it from the output. We replace it with a blank line which will
         // get consumed by later processing.
         lines[i] = '';
       }
     }
   }
 
   /// Parse the given [lines] of markdown to a series of AST nodes.
   List<Node> parseLines(List<String> lines) {
-    final parser = new BlockParser(lines, this);
+    var parser = new BlockParser(lines, this);
 
-    final blocks = [];
+    var blocks = <Node>[];
     while (!parser.isDone) {
-      for (final syntax in BlockSyntax.syntaxes) {
+      for (var syntax in BlockSyntax.syntaxes) {
         if (syntax.canParse(parser)) {
-          final block = syntax.parse(parser);
+          var block = syntax.parse(parser);
           if (block != null) blocks.add(block);
           break;
         }
       }
     }
 
     return blocks;
   }
 
   /// Takes a string of raw text and processes all inline markdown tags,
   /// returning a list of AST nodes. For example, given ``"*this **is** a*
   /// `markdown`"``, returns:
   /// `<em>this <strong>is</strong> a</em> <code>markdown</code>`.
   List<Node> parseInline(String text) => new InlineParser(text, this).parse();
 }
 
 class Link {
   final String id;
   final String url;
   final String title;
   Link(this.id, this.url, this.title);
 }