Simplify head emission a bit.

lib/dom/scripts/systemnative.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 systems to generate
 native binding from the IDL database."""
 
 import emitter
 import os
@@ skipping 772 matching lines @@
     invocation = self._GenerateWebCoreInvocation(function_expression, cpp_arguments,
         operation.type.id, operation.ext_attrs, operation.raises)
     self._GenerateNativeCallback(cpp_callback_name,
         parameter_definitions=parameter_definitions_emitter.Fragments(),
         needs_receiver=not operation.is_static, invocation=invocation,
         raises_exceptions=raises_exceptions)
 
   def _GenerateNativeCallback(self, callback_name, parameter_definitions,
       needs_receiver, invocation, raises_exceptions, runtime_check=None):
 
-    head = parameter_definitions
+    head_emitter = emitter.Emitter()
 
     if needs_receiver:
-      head = emitter.Format(
-          '        $WEBCORE_CLASS_NAME* receiver = DartDOMWrapper::receiver< $WEBCORE_CLASS_NAME >(args);\n'
-          '$HEAD\n',
-          WEBCORE_CLASS_NAME=self._interface_type_info.native_type(),
-          HEAD=head)
+      head_emitter.Emit(
+          '        $WEBCORE_CLASS_NAME* receiver = DartDOMWrapper::receiver< $WEBCORE_CLASS_NAME >(args);\n',
+          WEBCORE_CLASS_NAME=self._interface_type_info.native_type())
 
     if runtime_check:
-      head = emitter.Format(
-          '$RUNTIME_CHECK\n'
-          '$HEAD\n',

[podivilov, 2012/07/16 15:43:16]

Is it ok to change the order?

[Anton Muhin, 2012/07/16 15:46:45]

That should be, but let me lift it up to keep the former semantics.

-          RUNTIME_CHECK=runtime_check,
-          HEAD=head)
+      head_emitter.Emit(

[podivilov, 2012/07/16 15:43:16]

Maybe just emit(runtime_check)?

[Anton Muhin, 2012/07/16 15:46:45]

Missing trailing \n, let's keep it as is for now.

+          '$RUNTIME_CHECK\n',
+          RUNTIME_CHECK=runtime_check)
+
+    head_emitter.Emit(
+        '$PARAMETE_DEFINITIONS\n',
+        PARAMETE_DEFINITIONS=parameter_definitions)
 
     body = emitter.Format(
         '    {\n'
         '$HEAD'
         '$INVOCATION'
         '        return;\n'
         '    }\n',
-        HEAD=head,
+        HEAD=head_emitter.Fragments(),
         INVOCATION=invocation)
 
     if raises_exceptions:
       body = emitter.Format(
           '    Dart_Handle exception = 0;\n'
           '$BODY'
           '\n'
           'fail:\n'
           '    Dart_ThrowException(exception);\n'
           '    ASSERT_NOT_REACHED();\n',
@@ skipping 117 matching lines @@
 
 def _IsArgumentOptionalInWebCore(argument):
   return IsOptional(argument) and not 'Callback' in argument.ext_attrs
 
 def _ToWebKitName(name):
   name = name[0].lower() + name[1:]
   name = re.sub(r'^(hTML|uRL|jS|xML|xSLT)', lambda s: s.group(1).lower(),
                 name)
   return re.sub(r'^(create|exclusive)', lambda s: 'is' + s.group(1).capitalize(),
                 name)