Delegates Decorator

My study of the @delegates decorator and GetAttr from fastcore.

I follow https://www.fast.ai/posts/2019-08-06-delegation.html

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

class Student(Person):
    def __init__(self, name, age, grade):
        super().__init__(name, age)
        self.grade = grade

student = Student("Alice", 12, 'A')
print(student.name, student.age, student.grade)

Alice 12 A

kid = Student("Uma", 5.5, 'Good Kid!')
print(kid.name, kid.age, kid.grade)

Uma 5.5 Good Kid!

%pip install fastcore

from fastcore.meta import delegates

class Person:
    def __init__(self, name, age, **kwargs):
        self.name = name
        self.age = age

@delegates()
class Student(Person):
    def __init__(self, name, age, grade, **kwargs):
        super().__init__(name, age, **kwargs)
        self.grade = grade

child = Student("Amira", 6, grade='A', school='XYZ')
child.__dict__

{'name': 'Amira', 'age': 6, 'grade': 'A'}

from fastcore.basics import GetAttr

class Strawberry(GetAttr):
    def __init__(self, color, variety):
        self.color, self.variety = color, variety
        self.default = color

s = Strawberry('red', 'Pegasus')
s.color, s.variety, s.default

('red', 'Pegasus', 'red')

[s for s in dir(s) if not s.startswith('_')]

['capitalize',
 'casefold',
 'center',
 'color',
 'count',
 'default',
 'encode',
 'endswith',
 'expandtabs',
 'find',
 'format',
 'format_map',
 'index',
 'isalnum',
 'isalpha',
 'isascii',
 'isdecimal',
 'isdigit',
 'isidentifier',
 'islower',
 'isnumeric',
 'isprintable',
 'isspace',
 'istitle',
 'isupper',
 'join',
 'ljust',
 'lower',
 'lstrip',
 'maketrans',
 'partition',
 'removeprefix',
 'removesuffix',
 'replace',
 'rfind',
 'rindex',
 'rjust',
 'rpartition',
 'rsplit',
 'rstrip',
 'split',
 'splitlines',
 'startswith',
 'strip',
 'swapcase',
 'title',
 'translate',
 'upper',
 'variety',
 'zfill']

def play(game, player='Daddy', num_players=2):
    print(f'{player} is playing {game}')

play('chess', 'Mehdiya')

Mehdiya is playing chess

@delegates(play)
def play_chess(player, speed='blitz', **kwargs):
    play('chess', player)

play_chess('Uma')

Uma is playing chess

print(play_chess.__signature__)

(player, speed='blitz', *, num_players=2)

import inspect
print(inspect.signature(play_chess))

(player, speed='blitz', *, num_players=2)

print(inspect.signature(play))

(game, player='Daddy', num_players=2)