SubClasskKw Usage

SubClasskKw decorator that requires args of a function to match or be a subclass of types specificed in constructor. Each arg can have seperate rules applied.

Includes features:

ftype

opt_logger

opt_return

type_instance_check

SubClasskKw constructor args arg_info and rules work together. arg_info is a dictionary with a key of str that matches an arg name of the function that is being decorated. arg_info value is one of the following:

int is an index of an item in rules

type a type to match

arg_info can be mixed.

types is a list of type to match.

Example Usage

Sample Classes

from enum import IntEnum, auto

class Color(IntEnum):
    RED = auto()
    GREEN = auto()
    BLUE = auto()

    def __str__(self) -> str:
        return self._name_

class Base:
    def __str__(self) -> str:
        return self.__class__.__name__
class Obj:
    def __str__(self) -> str:
        return self.__class__.__name__
class Foo(Base): pass
class Bar(Foo): pass
class FooBar(Bar): pass
class ObjFoo(Obj): pass

SubClasskKw decorated function.

from kwhelp.decorator import SubClasskKw

@SubClasskKw(arg_info={"first": 0, "second": 0, "obj": 0, "color": 1},
            types=[(Foo, Obj), Color])
def myfunc(first, second, **kwargs):
    color = kwargs.get("color", Color.BLUE)
    return (str(first), str(second), str(kwargs['obj']), str(color))

>>> result = myfunc(first=Foo(), second=ObjFoo(), obj=FooBar())
>>> print(result)
('Foo', 'ObjFoo', 'FooBar', 'BLUE')

>>> result = myfunc(first=Foo(), second=ObjFoo(), color=Color.RED, obj=FooBar())
>>> print(result)
('Foo', 'ObjFoo', 'FooBar', 'RED')

If types fail validation then a TypeError is raised.

>>> result = myfunc(first=Foo(), second=ObjFoo(), color=1, obj=FooBar())
TypeError: Arg 'color' is expected to be of a subclass of 'Color'.
SubClasskKw decorator error.

SubClasskKw arg_info contains types and indexes. Types of arg_info are requied to match function arguments directly. Indexes are an index of types that match function arguments.

from kwhelp.decorator import SubClasskKw

@SubClasskKw(arg_info={"first": 0, "second": 0, "obj": 0, "color": Color},
            types=[(Foo, Obj), Color])
def myfunc(first, second, **kwargs):
    color = kwargs.get("color", Color.BLUE)
    return (str(first), str(second), str(kwargs['obj']), str(color))

>>> result = myfunc(first=Foo(), second=ObjFoo(), obj=FooBar())
>>> print(result)
('Foo', 'ObjFoo', 'FooBar', 'BLUE')

>>> result = myfunc(first=Foo(), second=ObjFoo(), color=1, obj=FooBar())
TypeError: Arg 'color' is expected to be of a subclass of 'Color'.
SubClasskKw decorator error.

Primitive Types

In python numbers and str instances are classes. SubClasskKw can also be used to test for numbers and strings.

from kwhelp.decorator import SubClasskKw

@SubClasskKw(arg_info={"first": 0, "second": 0, "obj": 0, "last": 1},
            types=[(int, float), str])
def myfunc(first, second, **kwargs):
    last = kwargs.get("last", "The End!")
    return (first, second, kwargs['obj'], last)

>>> result = myfunc(first=22.55, second=555, obj=-12.45, last="!!!")
>>> print(result)
(22.55, 555, -12.45, '!!!')

>>> result = myfunc(first=22.55, second=555, obj=None, last="!!!")
>>> print(result)
TypeError: Arg 'obj' is expected to be of a subclass of 'float' or 'int'.
SubClasskKw decorator error.