Generate static factories with optional arguments.

sdk/lib/html/scripts/systemhtml.py

 #!/usr/bin/python
 # Copyright (c) 2012, 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.
 
 """This module provides shared functionality for the system to generate
 Dart:html APIs from the IDL database."""
 
 import emitter
 import os
@@ skipping 452 matching lines @@
     return (self._template_loader.TryLoad(template_file) or
             self._template_loader.Load('dart2js_impl.darttemplate'))
 
   def StartInterface(self, members_emitter):
     self._members_emitter = members_emitter
 
   def FinishInterface(self):
     pass
 
   def EmitStaticFactory(self, constructor_info):
-    arguments = constructor_info.ParametersAsArgumentList()
-    if arguments:
-      arguments = ', ' + arguments
-    self._members_emitter.Emit(
-        "  static $INTERFACE_NAME _create($PARAMETERS_DECLARATION) => JS("
-          "'$INTERFACE_NAME', "
-          "'new $CONSTRUCTOR_NAME($ARGUMENTS_PATTERN)'$ARGUMENTS);\n",
-        INTERFACE_NAME=self._interface_type_info.interface_name(),
-        PARAMETERS_DECLARATION=constructor_info.ParametersDeclaration(
-            self._DartType),
-        CONSTRUCTOR_NAME=constructor_info.name or self._interface.doc_js_name,
-        ARGUMENTS_PATTERN=','.join(['#'] * len(constructor_info.param_infos)),
-        ARGUMENTS=arguments)
+    has_optional = any(param_info.is_optional
+        for param_info in constructor_info.param_infos)
+
+    def FormatJS(index):
+      arguments = constructor_info.ParametersAsArgumentList(index)
+      if arguments:
+        arguments = ', ' + arguments
+      return "JS('%s', 'new %s(%s)'%s)" % (
+          self._interface_type_info.interface_name(),
+          constructor_info.name or self._interface.doc_js_name,
+          ','.join(['#'] * index),
+          arguments)
+
+    if not has_optional:
+      self._members_emitter.Emit(
+          "  static $INTERFACE_NAME _create($PARAMETERS_DECLARATION) => $JS;\n",
+          INTERFACE_NAME=self._interface_type_info.interface_name(),
+          PARAMETERS_DECLARATION=constructor_info.ParametersDeclaration(
+              self._DartType),
+          JS=FormatJS(len(constructor_info.param_infos)))
+    else:
+      dispatcher_emitter = self._members_emitter.Emit(
+          "  static $INTERFACE_NAME _create($PARAMETERS_DECLARATION) {\n"
+          "$!DISPATCHER"
+          "    return $JS;\n"
+          "  }\n",
+          INTERFACE_NAME=self._interface_type_info.interface_name(),
+          PARAMETERS_DECLARATION=constructor_info.ParametersDeclaration(
+              self._DartType),
+          JS=FormatJS(len(constructor_info.param_infos)))
+
+      for index, param_info in enumerate(constructor_info.param_infos):
+        if param_info.is_optional:
+          dispatcher_emitter.Emit(
+            "    if (!?$OPT_PARAM_NAME) {\n"
+            "      return $JS;\n"
+            "    }\n",
+            OPT_PARAM_NAME=constructor_info.param_infos[index].name,
+            JS=FormatJS(index))
 
   def SecondaryContext(self, interface):
     if interface is not self._current_secondary_parent:
       self._current_secondary_parent = interface
       self._members_emitter.Emit('\n  // From $WHERE\n', WHERE=interface.id)
 
   def AddIndexer(self, element_type):
     """Adds all the methods required to complete implementation of List."""
     # We would like to simply inherit the implementation of everything except
     # length, [], and maybe []=.  It is possible to extend from a base
@@ skipping 506 matching lines @@
     for library_name in libraries:
       self._libraries[library_name] = DartLibrary(
           library_name, template_loader, library_type, output_dir)
 
   def AddFile(self, basename, library_name, path):
     self._libraries[library_name].AddFile(path)
 
   def Emit(self, emitter, auxiliary_dir):
     for lib in self._libraries.values():
       lib.Emit(emitter, auxiliary_dir)