Simplify head emission a bit.

lib/dom/scripts/systemnative.py

Index: lib/dom/scripts/systemnative.py
diff --git a/lib/dom/scripts/systemnative.py b/lib/dom/scripts/systemnative.py
index add05bdc11cfeea3f510259ac6ca1fb7e51f06cc..830cf14f58af9028af558ca57f01a08bae21268b 100644
--- a/lib/dom/scripts/systemnative.py
+++ b/lib/dom/scripts/systemnative.py
@@ -790,21 +790,21 @@ class NativeImplementationGenerator(systembase.BaseGenerator):
   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'
@@ -812,7 +812,7 @@ class NativeImplementationGenerator(systembase.BaseGenerator):
         '$INVOCATION'
         '        return;\n'
         '    }\n',
-        HEAD=head,
+        HEAD=head_emitter.Fragments(),
         INVOCATION=invocation)
 
     if raises_exceptions: