Add union types to the analysis server API spec.

pkg/analysis_server/tool/spec/from_html.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.
 
 /**
  * Code for reading an HTML API description.
  */
 library from.html;
 
 import 'dart:io';
@@ skipping 33 matching lines @@
     if (!attributesFound.contains(expectedAttribute)) {
       throw new Exception(
           '${element.localName} must contain attribute ${expectedAttribute}');
     }
   }
 }
 
 const List<String> specialElements = const ['domain', 'feedback',
     'object', 'refactorings', 'refactoring', 'type', 'types', 'request',
     'notification', 'params', 'result', 'field', 'list', 'map', 'enum', 'key',
-    'value', 'options', 'ref', 'code', 'version'];
+    'value', 'options', 'ref', 'code', 'version', 'union'];
 
 typedef void ElementProcessor(dom.Element element);
 typedef void TextProcessor(dom.Text text);
 
 void recurse(dom.Element parent, Map<String, ElementProcessor>
     elementProcessors) {
   for (String key in elementProcessors.keys) {
     if (!specialElements.contains(key)) {
       throw new Exception('$key is not a special element');
     }
@@ skipping 231 matching lines @@
   checkAttributes(html, ['event']);
   String event = html.attributes['event'];
   TypeDecl params;
   recurse(html, {
     'params': (dom.Element child) {
       params = typeObjectFromHtml(child);
     }
   });
   return new Notification(domainName, event, params, html);
 }
+/**
+ * Create a single of [TypeDecl] corresponding to the type defined inside the
+ * given HTML element.
+ */
+TypeDecl processContentsAsType(dom.Element html) {
+  List<TypeDecl> types = processContentsAsTypes(html);
+  if (types.length != 1) {
+    throw new Exception('Exactly one type must be specified');
+  }
+  return types[0];
+}
 
 /**
- * Create a [TypeDecl] from an HTML description.  The following forms are
- * supported.
+ * Create a list of [TypeDecl]s corresponding to the types defined inside the
+ * given HTML element.  The following forms are supported.
  *
  * To refer to a type declared elsewhere (or a built-in type):
  *
  *   <ref>typeName</ref>
  *
  * For a list: <list>ItemType</list>
  *
  * For a map: <map><key>KeyType</key><value>ValueType</value></map>
  *
  * For a JSON object:
  *
  *   <object>
  *     <field name="...">...</field> <!-- zero or more -->
  *   </object>
  *
  * For an enum:
  *
  *   <enum>
  *     <value>...</value> <!-- zero or more -->
  *   </enum>
+ *
+ * For a union type:
+ *   <union>
+ *     TYPE <!-- zero or more -->
+ *   </union>
  */
-TypeDecl processContentsAsType(dom.Element html) {
+List<TypeDecl> processContentsAsTypes(dom.Element html) {
   List<TypeDecl> types = <TypeDecl>[];
   recurse(html, {
     'object': (dom.Element child) {
       types.add(typeObjectFromHtml(child));
     },
     'list': (dom.Element child) {
       checkAttributes(child, []);
       types.add(new TypeList(processContentsAsType(child), child));
     },
     'map': (dom.Element child) {
@@ skipping 21 matching lines @@
         throw new Exception('Value type not specified');
       }
       types.add(new TypeMap(keyType, valueType, child));
     },
     'enum': (dom.Element child) {
       types.add(typeEnumFromHtml(child));
     },
     'ref': (dom.Element child) {
       checkAttributes(child, []);
       types.add(new TypeReference(innerText(child), child));
+    },
+    'union': (dom.Element child) {
+      checkAttributes(child, []);
+      types.add(new TypeUnion(processContentsAsTypes(child), child));
     }
   });
-  if (types.length != 1) {
-    throw new Exception('Exactly one type must be specified');
-  }
-  return types[0];
+  return types;
 }
 
 /**
  * Create a [TypeEnum] from an HTML description.
  */
 TypeEnum typeEnumFromHtml(dom.Element html) {
   checkName(html, 'enum');
   checkAttributes(html, []);
   List<TypeEnumValue> values = <TypeEnumValue>[];
   recurse(html, {
@@ skipping 87 matching lines @@
 
 /**
  * Read the API description from the file 'spec_input.html'.
  */
 Api readApi() {
   File htmlFile = new File('spec_input.html');
   String htmlContents = htmlFile.readAsStringSync();
   dom.Document document = parser.parse(htmlContents);
   return apiFromHtml(document.firstChild);
 }