def make_type_checker(annotation):
"""Builds a PyTypeChecker for the given type annotation."""
if type_annotations.is_generic_union(annotation):
type_args = type_annotations.get_generic_type_args(annotation)
options = [make_type_checker(t) for t in type_args]
return _api_dispatcher.MakeUnionChecker(options)
elif type_annotations.is_generic_list(annotation):
type_args = type_annotations.get_generic_type_args(annotation)
if len(type_args) != 1:
raise AssertionError(
"Expected List[...] to have a single type parameter")
elt_type = make_type_checker(type_args[0])
return _api_dispatcher.MakeListChecker(elt_type)
elif isinstance(annotation, type):
if annotation not in _is_instance_checker_cache:
checker = _api_dispatcher.MakeInstanceChecker(annotation)
_is_instance_checker_cache[annotation] = checker
return _is_instance_checker_cache[annotation]
elif annotation is None:
return make_type_checker(type(None))
else:
raise ValueError(
f"Type annotation {annotation} is not currently supported"
" by dispatch. Supported annotations: type objects, "
" List[...], and Union[...]")
def contains_cls(x):
"""Returns true if `x` contains `cls`."""
if isinstance(x, dict):
return any(contains_cls(v) for v in x.values())
elif x is cls:
return True
elif (type_annotations.is_generic_list(x)
or type_annotations.is_generic_union(x)):
type_args = type_annotations.get_generic_type_args(x)
return any(contains_cls(arg) for arg in type_args)
else:
return False
def make_type_checker(annotation):
"""Builds a PyTypeChecker for the given type annotation."""
if type_annotations.is_generic_union(annotation):
type_args = type_annotations.get_generic_type_args(annotation)
# If the union contains two or more simple types, then use a single
# InstanceChecker to check them.
simple_types = [t for t in type_args if isinstance(t, type)]
simple_types = tuple(sorted(simple_types, key=id))
if len(simple_types) > 1:
if simple_types not in _is_instance_checker_cache:
checker = _api_dispatcher.MakeInstanceChecker(*simple_types)
_is_instance_checker_cache[simple_types] = checker
options = ([_is_instance_checker_cache[simple_types]] + [
make_type_checker(t)
for t in type_args if not isinstance(t, type)
])
return _api_dispatcher.MakeUnionChecker(options)
options = [make_type_checker(t) for t in type_args]
return _api_dispatcher.MakeUnionChecker(options)
elif type_annotations.is_generic_list(annotation):
type_args = type_annotations.get_generic_type_args(annotation)
if len(type_args) != 1:
raise AssertionError(
"Expected List[...] to have a single type parameter")
elt_type = make_type_checker(type_args[0])
return _api_dispatcher.MakeListChecker(elt_type)
elif isinstance(annotation, type):
if annotation not in _is_instance_checker_cache:
checker = _api_dispatcher.MakeInstanceChecker(annotation)
_is_instance_checker_cache[annotation] = checker
return _is_instance_checker_cache[annotation]
elif annotation is None:
return make_type_checker(type(None))
else:
raise ValueError(
f"Type annotation {annotation} is not currently supported"
" by dispatch. Supported annotations: type objects, "
" List[...], and Union[...]")
