def test_override(self):
from generic.registry import Registry
from generic.registry import SimpleAxis
registry = Registry(('name', SimpleAxis()))
registry.register(1, name='foo')
registry.override(2, name='foo')
self.assertEqual(registry.lookup('foo'), 2)
def test_override(self):
from generic.registry import Registry
from generic.registry import SimpleAxis
registry = Registry(('name', SimpleAxis()))
registry.register(1, name='foo')
registry.override(2, name='foo')
self.assertEqual(registry.lookup('foo'), 2)
class FunctionDispatcher(object):
""" Multidispatcher for functions
This object dispatch calls to function by its argument types. Usually it is
produced by :func:`.multifunction` decorator.
You should not manually create objects of this type.
"""
def __init__(self, argspec, params_arity):
""" Initialize dispatcher with ``argspec`` of type
:class:`inspect.ArgSpec` and ``params_arity`` that represent number
params."""
# Check if we have enough positional arguments for number of type params
if arity(argspec) < params_arity:
raise TypeError("Not enough positional arguments "
"for number of type parameters provided.")
self.argspec = argspec
self.params_arity = params_arity
axis = [("arg_%d" % n, TypeAxis()) for n in range(params_arity)]
self.registry = Registry(*axis)
def check_rule(self, rule, *argtypes):
# Check if we have the right number of parametrized types
if len(argtypes) != self.params_arity:
raise TypeError("Wrong number of type parameters.")
# Check if we have the same argspec (by number of args)
rule_argspec = inspect.getargspec(rule)
if not is_equalent_argspecs(rule_argspec, self.argspec):
raise TypeError("Rule does not conform "
"to previous implementations.")
def register_rule(self, rule, *argtypes):
""" Register new ``rule`` for ``argtypes``."""
self.check_rule(rule, *argtypes)
self.registry.register(rule, *argtypes)
def override_rule(self, rule, *argtypes):
""" Override ``rule`` for ``argtypes``."""
self.check_rule(rule, *argtypes)
self.registry.override(rule, *argtypes)
def lookup_rule(self, *args):
""" Lookup rule by ``args``. Returns None if no rule was found."""
args = args[:self.params_arity]
rule = self.registry.lookup(*args)
if rule is None:
raise TypeError("No available rule found for %r" % (args,))
return rule
def when(self, *argtypes):
""" Decorator for registering new case for multifunction
New case will be registered for types identified by ``argtypes``. The
length of ``argtypes`` should be equal to the length of ``argtypes``
argument were passed corresponding :func:`.multifunction` call, which
also indicated the number of arguments multifunction dispatches on.
"""
def register_rule(func):
self.register_rule(func, *argtypes)
return self
return register_rule
@property
def otherwise(self):
""" Decorator which registeres "catch-all" case for multifunction"""
def register_rule(func):
self.register_rule(func, [object]*self.params_arity)
return self
return register_rule
def override(self, *argtypes):
""" Decorator for overriding case for ``argtypes``"""
def override_rule(func):
self.override_rule(func, *argtypes)
return self
return override_rule
def __call__(self, *args, **kwargs):
""" Dispatch call to appropriate rule."""
rule = self.lookup_rule(*args)
return rule(*args, **kwargs)
class FunctionDispatcher(object):
""" Multidispatcher for functions
This object dispatch calls to function by its argument types. Usually it is
produced by :func:`.multifunction` decorator.
You should not manually create objects of this type.
"""
def __init__(self, argspec, params_arity):
""" Initialize dispatcher with ``argspec`` of type
:class:`inspect.ArgSpec` and ``params_arity`` that represent number
params."""
# Check if we have enough positional arguments for number of type params
if arity(argspec) < params_arity:
raise TypeError("Not enough positional arguments "
"for number of type parameters provided.")
self.argspec = argspec
self.params_arity = params_arity
axis = [("arg_%d" % n, TypeAxis()) for n in range(params_arity)]
self.registry = Registry(*axis)
def check_rule(self, rule, *argtypes):
# Check if we have the right number of parametrized types
if len(argtypes) != self.params_arity:
raise TypeError("Wrong number of type parameters.")
# Check if we have the same argspec (by number of args)
rule_argspec = inspect.getargspec(rule)
if not is_equalent_argspecs(rule_argspec, self.argspec):
raise TypeError("Rule does not conform "
"to previous implementations.")
def register_rule(self, rule, *argtypes):
""" Register new ``rule`` for ``argtypes``."""
self.check_rule(rule, *argtypes)
self.registry.register(rule, *argtypes)
def override_rule(self, rule, *argtypes):
""" Override ``rule`` for ``argtypes``."""
self.check_rule(rule, *argtypes)
self.registry.override(rule, *argtypes)
def lookup_rule(self, *args):
""" Lookup rule by ``args``. Returns None if no rule was found."""
args = args[:self.params_arity]
rule = self.registry.lookup(*args)
if rule is None:
raise TypeError("No available rule found for %r" % (args, ))
return rule
def when(self, *argtypes):
""" Decorator for registering new case for multifunction
New case will be registered for types identified by ``argtypes``. The
length of ``argtypes`` should be equal to the length of ``argtypes``
argument were passed corresponding :func:`.multifunction` call, which
also indicated the number of arguments multifunction dispatches on.
"""
def register_rule(func):
self.register_rule(func, *argtypes)
return self
return register_rule
@property
def otherwise(self):
""" Decorator which registeres "catch-all" case for multifunction"""
def register_rule(func):
self.register_rule(func, [object] * self.params_arity)
return self
return register_rule
def override(self, *argtypes):
""" Decorator for overriding case for ``argtypes``"""
def override_rule(func):
self.override_rule(func, *argtypes)
return self
return override_rule
def __call__(self, *args, **kwargs):
""" Dispatch call to appropriate rule."""
rule = self.lookup_rule(*args)
return rule(*args, **kwargs)
