Fixed [:foo:]-style markdown links and added lookup within the library

pkg/docgen/lib/docgen.dart

Index: pkg/docgen/lib/docgen.dart
diff --git a/pkg/docgen/lib/docgen.dart b/pkg/docgen/lib/docgen.dart
index 271684dd0729eca6b767f1bde97e676279e40497..d065698374a04fe626280838e4d6bc69d06043cf 100644
--- a/pkg/docgen/lib/docgen.dart
+++ b/pkg/docgen/lib/docgen.dart
@@ -47,6 +47,10 @@ ClassMirror _currentClass;
 /// Current member being documented to be used for comment links.
 MemberMirror _currentMember;
 
+/// Add support for [:foo:]-style code to the markdown parser.

[Emily Fortuna, 2013/08/02 23:26:55]

nit: can we make this comment slightly clearer: support for [:foo:]-style code
comments...

[Tate Mandel, 2013/08/02 23:54:36]

Done.

+List<markdown.InlineSyntax> markdownSyntaxes = 
+  [new markdown.CodeSyntax(r'\[:\s?((?:.|\n)*?)\s?:\]')];
+ 
 /// Resolves reference links in doc comments.
 markdown.Resolver linkResolver;
 
@@ -323,7 +327,8 @@ String _commentToHtml(DeclarationMirror mirror) {
   });
   
   commentText = commentText == null ? '' : 
-      markdown.markdownToHtml(commentText.trim(), linkResolver: linkResolver);
+      markdown.markdownToHtml(commentText.trim(), linkResolver: linkResolver,
+          inlineSyntaxes: markdownSyntaxes);
   return commentText;
 }
 
@@ -339,7 +344,12 @@ markdown.Node fixReference(String name, LibraryMirror currentLibrary,
   else {
     var classScope = currentClass == null ?
         null : currentClass.lookupInScope(name);
-    reference = classScope != null ? classScope.qualifiedName : name;
+    if (classScope != null) reference = classScope.qualifiedName;

[Emily Fortuna, 2013/08/02 23:26:55]

if you have an else branch, go ahead and put the if branch also on a separate
line:
if (classScope...) {
  reference = ...;
} else  {
 ...
}

[Tate Mandel, 2013/08/02 23:54:36]

Done.

+    else {
+      var libraryScope = currentLibrary == null ?
+          null : currentLibrary.lookupInScope(name);
+      reference = libraryScope != null ? libraryScope.qualifiedName : name;
+    }
   }
   return new markdown.Element.text('a', reference);
 }
@@ -620,7 +630,7 @@ class Class extends Indexable {
    */
   void makeValid() {
     var library = entityMap[owner];
-    if (!library.classes.containsKey(name)) {
+    if (library != null && !library.classes.containsKey(name)) {
       this.isPrivate = true;
       // Since we are now making the mixin a private class, make all elements 
       // with the mixin as an owner private too.