def common_super_type_of_types_is_passed_type_that_is_super_type_of_all_other_types(self):
first_type = types.structural_type("first", [
types.attr("a", types.int_type),
types.attr("b", types.str_type),
])
second_type = types.structural_type("second", [
types.attr("a", types.int_type),
])
assert_equal(second_type, types.common_super_type([first_type, second_type]))
def rescursive_structural_types_do_not_cause_stack_overflow(self):
recursive1 = types.structural_type("recursive1")
recursive1.attrs.add("uh_oh", types.func([], recursive1))
recursive2 = types.structural_type("recursive2")
recursive2.attrs.add("uh_oh", types.func([], recursive2))
assert not types.is_sub_type(
recursive1,
recursive2,
)
def class_type_is_not_subtype_of_structural_type_if_it_is_missing_attrs(self):
cls = types.class_type("Person")
structural_type = types.structural_type("HasName", [
types.attr("name", types.str_type),
])
assert not types.is_sub_type(structural_type, cls)
assert not types.is_sub_type(cls, structural_type)
def class_type_is_not_subtype_of_structural_type_if_attr_is_strict_supertype_of_attr_on_structural_type(self):
cls = types.class_type("Person", [
types.attr("name", types.object_type),
])
structural_type = types.structural_type("HasName", [
types.attr("name", types.str_type),
])
assert not types.is_sub_type(structural_type, cls)
assert not types.is_sub_type(cls, structural_type)
def class_type_is_subtype_of_structural_type_if_it_has_subset_of_attrs(self):
# TODO: how to handle sub-typing of mutable attrs
cls = types.class_type("Person", [
types.attr("name", types.str_type),
types.attr("number_of_hats", types.int_type),
])
structural_type = types.structural_type("HasName", [
types.attr("name", types.str_type),
])
assert types.is_sub_type(structural_type, cls)
assert not types.is_sub_type(cls, structural_type)
def type_of_structural_type_is_as_definition():
type_bindings = {
"str": types.meta_type(types.str_type),
"int": types.meta_type(types.int_type),
}
node = nodes.structural_type("Song", [
("description", nodes.ref("str")),
("length", nodes.ref("int")),
])
context = update_context(node, type_bindings=type_bindings)
declared_type = context.lookup_name("Song")
assert types.is_meta_type(declared_type)
expected_type = types.structural_type("Song", [
types.attr("description", types.str_type),
types.attr("length", types.int_type),
])
assert types.is_equivalent_type(expected_type, declared_type.type)
