def on(self, obj):
""" Wraps specified object's methods in @expects/@returns decorators,
according to those defined on interface's method.
"""
for method_name, method in self._interface.__dict__.iteritems():
if not isinstance(method, Method):
continue
if not method.is_checked():
continue
obj_method = getattr(obj, method_name, None)
if not obj_method:
exc_tuple = (obj, method_name, self._interface.__name__)
raise TypeError, "Object (%r) does have required method %s of interface %s" % exc_tuple
# decorate with @returns
if method._returns:
returns_decorator = ReturnValueDecorator(method._returns)
obj_method = returns_decorator(obj_method)
# decorate with @expects
if method._arguments:
expects_decorator = ExpectedParametersDecorator()
expects_decorator.arg_spec = method._arguments
obj_method = expects_decorator(obj_method)
setattr(obj, method_name, obj_method)
return obj
def overloaded_function(*args, **kwargs):
for func in typed_functions: # TODO: more intelligent overload resolution
arg_spec = getattr(func, '_arguments', None)
if not arg_spec: continue
# TODO: encapsulate this mechanism inside EPD class
expects_decorator = ExpectedParametersDecorator()
expects_decorator.arg_spec = arg_spec
expects_decorator.omit_self = getattr(func, '_has_self', False)
try:
expects_decorator._validate_arguments(args, kwargs)
except ArgumentError:
continue
return func(*args, **kwargs)