Appending working for library_list.json

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 a51ab86d0ad85fda06bf9eb98a81f24782ca1fe0..caf1067225125550c14fd188a4715b32acae65f8 100644
--- a/pkg/docgen/lib/docgen.dart
+++ b/pkg/docgen/lib/docgen.dart
@@ -244,26 +244,50 @@ void _documentLibraries(List<LibraryMirror> libs, {bool includeSdk: false,
   if (parseSdk) entityMap['dart.core.Object'].subclasses.clear();
 
   var filteredEntities = entityMap.values.where(_isVisible);
-  // Output libraries and classes to file after all information is generated.
-  filteredEntities.where((e) => e is Class || e is Library).forEach((output) {
-    _writeIndexableToFile(output, outputToYaml);
-  });
+  
   // Outputs a YAML or JSON file with all libraries and their preview comments 
   // after creating all libraries. This will help the viewer know what 
   // libraries are available to read in.
-  var libraryMap = {
-    'libraries' : filteredEntities.where((e) => 
-        e is Library).map((e) => e.previewMap).toList(),
-    'introduction' : introduction == '' ? 
-        '' : markdown.markdownToHtml(new File(introduction).readAsStringSync(),
-            linkResolver: linkResolver, inlineSyntaxes: markdownSyntaxes)
-  };
-  if (outputToYaml) {
-    _writeToFile(getYamlString(libraryMap), 'library_list.yaml', 
-        append: append);
+  var libraryMap;
+  if (append) {
+    var docsDir = listDir('docs');
+    if (docsDir.contains('docs/library_list.json')){

[Bob Nystrom, 2013/08/16 20:51:10]

Nit: space before "{".

Also, I would flip the condition and do the throw first, then you don't need an
else:

if (!docsDir.contains(...) {
  throw new StateError(...);
}

libraryMap = ...

[janicejl, 2013/08/16 21:33:45]

Done.

+      libraryMap = parse(new File('docs/library_list.json').readAsStringSync());
+    } else {
+      throw new StateError('No library_list.json.');
+    }
+    libraryMap['libraries'].addAll(filteredEntities.where((e) => 
+          e is Library).map((e) => e.previewMap).toList());

[Bob Nystrom, 2013/08/16 20:51:10]

Nit, how about wrapping this on ".", like:

libraryMap['libraries'].addAll(filteredEntities
    .where((e) => e is Library)
    .map((e) => e.previewMap));

Also, you don't need the .toList().

[janicejl, 2013/08/16 21:33:45]

Done.

+    if (introduction.isNotEmpty) {
+      var intro = libraryMap['introduction'];
+      if (intro.isNotEmpty) {
+        intro = intro + '<br/><br/>' + markdown.markdownToHtml(

[Bob Nystrom, 2013/08/16 20:51:10]

intro += '<br/><br/>'...

[Bob Nystrom, 2013/08/16 20:51:10]

You can get rid of some duplicate code:

var intro = libraryMap['introduction'];
if (intro.isNotEmpty) intro += '<br/><br/>';
intro += markdown.markdownToHtml(...);
libraryMap['introduction'] = intro;

[janicejl, 2013/08/16 21:33:45]

Done.

+            new File(introduction).readAsStringSync(), 
+                linkResolver: linkResolver, inlineSyntaxes: markdownSyntaxes);
+      } else {
+        intro = markdown.markdownToHtml(new File(introduction)
+            .readAsStringSync(), linkResolver: linkResolver, 
+                inlineSyntaxes: markdownSyntaxes);
+      }
+      libraryMap['introduction'] = intro;
+    }
+    outputToYaml = libraryMap['filetype'] == 'yaml';
   } else {
-    _writeToFile(stringify(libraryMap), 'library_list.json', append: append);
+    libraryMap = {
+      'libraries' : filteredEntities.where((e) => 
+          e is Library).map((e) => e.previewMap).toList(),
+      'introduction' : introduction == '' ? 
+          '' : markdown.markdownToHtml(new File(introduction)
+              .readAsStringSync(), linkResolver: linkResolver, 
+                  inlineSyntaxes: markdownSyntaxes), 
+      'filetype' : outputToYaml ? 'yaml' : 'json'
+    };
   }
+  _writeToFile(stringify(libraryMap), 'library_list.json');
+  // Output libraries and classes to file after all information is generated.
+  filteredEntities.where((e) => e is Class || e is Library).forEach((output) {
+    _writeIndexableToFile(output, outputToYaml);
+  });
   // Outputs all the qualified names documented with their type.
   // This will help generate search results.
   _writeToFile(filteredEntities.map((e) =>