pkg/docgen: support better const rendering of String, List, and empty Map

pkg/docgen/lib/src/model_helpers.dart

 // Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library docgen.model_helpers;
 
 import 'dart:collection';
 
 import '../../../../sdk/lib/_internal/compiler/implementation/mirrors/dart2js_mirrors.dart'
     as dart2js_mirrors;
 import '../../../../sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart'
     as dart2js_util;
 import '../../../../sdk/lib/_internal/compiler/implementation/mirrors/source_mirrors.dart';
 import '../../../../sdk/lib/_internal/libraries.dart';
 
 import 'library_helpers.dart' show includePrivateMembers;
 import 'models.dart';
 import 'package_helpers.dart';
 
+String getDefaultValue(ParameterMirror mirror) {
+  if (!mirror.hasDefaultValue) return null;
+  return getDefaultValueFromConstMirror(mirror.defaultValue);
+}
+
+String getDefaultValueFromConstMirror(
+    dart2js_mirrors.Dart2JsConstantMirror valueMirror) {
+
+  if (valueMirror is dart2js_mirrors.Dart2JsStringConstantMirror) {
+    return '"${valueMirror.reflectee}"';
+  }
+
+  if (valueMirror is dart2js_mirrors.Dart2JsListConstantMirror) {
+    var buffer = new StringBuffer('[');
+
+    var values = new Iterable.generate(valueMirror.length,
+        (i) => valueMirror.getElement(i))
+        .map((e) => getDefaultValueFromConstMirror(e));
+
+    buffer.writeAll(values, ', ');
+
+    buffer.write(']');
+    return buffer.toString();
+  }
+
+  if (valueMirror is dart2js_mirrors.Dart2JsMapConstantMirror) {
+    // TODO(kevmoo) Handle non-empty case
+    if (valueMirror.length == 0) return '{}';
+  }
+
+  // TODO(kevmoo) Handle consts of non-core types
+
+  return '${valueMirror}';
+}
+
 /// Returns a list of meta annotations assocated with a mirror.
 List<Annotation> createAnnotations(DeclarationMirror mirror,
     Library owningLibrary) {
   var annotationMirrors = mirror.metadata
       .where((e) => e is dart2js_mirrors.Dart2JsConstructedConstantMirror);
   var annotations = [];
   annotationMirrors.forEach((annotation) {
     var docgenAnnotation = new Annotation(annotation, owningLibrary);
     if (!_SKIPPED_ANNOTATIONS.contains(dart2js_util.qualifiedNameOf(
         docgenAnnotation.mirror))) {
@@ skipping 190 matching lines @@
   // the time.
   var sdkLibrary = LIBRARIES[dart2js_util.nameOf(mirror)];
   if (sdkLibrary != null) {
     return !sdkLibrary.documented;
   } else if (dart2js_util.nameOf(mirror).startsWith('_') || dart2js_util.nameOf(
       mirror).contains('._')) {
     return true;
   }
   return false;
 }