IDL: Support default values for dictionary members of union types

Source/bindings/scripts/v8_types.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
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@@ skipping 878 matching lines @@
 
 
 def literal_cpp_value(idl_type, idl_literal):
     """Converts an expression that is a valid C++ literal for this type."""
     # FIXME: add validation that idl_type and idl_literal are compatible
     literal_value = str(idl_literal)
     if idl_type.base_type in CPP_UNSIGNED_TYPES:
         return literal_value + 'u'
     return literal_value
 
+
+def union_literal_cpp_value(idl_type, idl_literal):

[haraken, 2015/02/18 15:09:04]

Can we merge literal_cpp_value and union_literal_cpp_value? (e.g., if idl_type
knows if it's a union type or not, we can switch the logic in
literal_cpp_value.)

[Jens Widell, 2015/02/18 15:14:39]

We can implement a single function that handles both IdlType and IdlUnionType,
yes. (It would contain the same amount of code, only arranged slightly
differently.)

That single function would then need to be on IdlTypeBase, and then it would
apply to the other types as well.

Generally, though, I prefer to keep the handling in two separate function, like
this, unless there's some other gain, such as possibility of code sharing.

+    if idl_literal.is_null:
+        return idl_type.name + '()'
+    elif idl_literal.idl_type == 'DOMString':
+        member_type = idl_type.string_member_type
+    elif idl_literal.idl_type in ('integer', 'float'):
+        member_type = idl_type.numeric_member_type
+    elif idl_literal.idl_type == 'boolean':
+        member_type = idl_type.boolean_member_type
+    else:
+        raise ValueError('Unsupported literal type: ' + idl_literal.idl_type)
+
+    return '%s::from%s(%s)' % (idl_type.name, member_type.name,
+                               member_type.literal_cpp_value(idl_literal))
+
 IdlType.literal_cpp_value = literal_cpp_value
+IdlUnionType.literal_cpp_value = union_literal_cpp_value
 
 
 ################################################################################
 # Utility properties for nullable types
 ################################################################################
 
 
 def cpp_type_has_null_value(idl_type):
     # - String types (String/AtomicString) represent null as a null string,
     #   i.e. one for which String::isNull() returns true.
@@ skipping 39 matching lines @@
     number_of_nullable_member_types_union)
 
 
 def includes_nullable_type_union(idl_type):
     # http://heycam.github.io/webidl/#dfn-includes-a-nullable-type
     return idl_type.number_of_nullable_member_types == 1
 
 IdlTypeBase.includes_nullable_type = False
 IdlNullableType.includes_nullable_type = True
 IdlUnionType.includes_nullable_type = property(includes_nullable_type_union)