import torch
import matplotlib.pyplot as plt
import random

import ipywidgets as widgets

def f(o): print('hi')

w = widgets.Button(description='Click me')

w

w.on_click(f)

from time import sleep

def slow_calculation():
    res = 0
    for i in range(5):
        res += i*i
        sleep(1)
    return res

slow_calculation()

def slow_calculation(cb=None):
    res = 0
    for i in range(5):
        res += i*i
        sleep(1)
        if cb: cb(i)
    return res

def show_progress(epoch):
    print(f"Awesome! We've finished epoch {epoch}!")

slow_calculation(show_progress)

slow_calculation(lambda o: print(f"Awesome! We've finished epoch {o}!"))

def show_progress(exclamation, epoch):
    print(f"{exclamation}! We've finished epoch {epoch}!")

slow_calculation(lambda o: show_progress("OK I guess", o))

def make_show_progress(exclamation):
    _inner = lambda epoch: print(f"{exclamation}! We've finished epoch {epoch}!")
    return _inner

slow_calculation(make_show_progress("Nice!"))

def make_show_progress(exclamation):
    # Leading "_" is generally understood to be "private"
    def _inner(epoch): print(f"{exclamation}! We've finished epoch {epoch}!")
    return _inner

slow_calculation(make_show_progress("Nice!"))

f2 = make_show_progress("Terrific")

slow_calculation(f2)

slow_calculation(make_show_progress("Amazing"))

from functools import partial

slow_calculation(partial(show_progress, "OK I guess"))

f2 = partial(show_progress, "OK I guess")

class ProgressShowingCallback():
    def __init__(self, exclamation="Awesome"): self.exclamation = exclamation
    def __call__(self, epoch): print(f"{self.exclamation}! We've finished epoch {epoch}!")

cb = ProgressShowingCallback("Just super")

slow_calculation(cb)

def f(*args, **kwargs): print(f"args: {args}; kwargs: {kwargs}")

f(3, 'a', thing1="hello")

def slow_calculation(cb=None):
    res = 0
    for i in range(5):
        if cb: cb.before_calc(i)
        res += i*i
        sleep(1)
        if cb: cb.after_calc(i, val=res)
    return res

class PrintStepCallback():
    def __init__(self): pass
    def before_calc(self, *args, **kwargs): print(f"About to start")
    def after_calc (self, *args, **kwargs): print(f"Done step")

slow_calculation(PrintStepCallback())

class PrintStatusCallback():
    def __init__(self): pass
    def before_calc(self, epoch, **kwargs): print(f"About to start: {epoch}")
    def after_calc (self, epoch, val, **kwargs): print(f"After {epoch}: {val}")

slow_calculation(PrintStatusCallback())

def slow_calculation(cb=None):
    res = 0
    for i in range(5):
        if cb and hasattr(cb,'before_calc'): cb.before_calc(i)
        res += i*i
        sleep(1)
        if cb and hasattr(cb,'after_calc'):
            if cb.after_calc(i, res):
                print("stopping early")
                break
    return res

class PrintAfterCallback():
    def after_calc (self, epoch, val):
        print(f"After {epoch}: {val}")
        if val>10: return True

slow_calculation(PrintAfterCallback())

class SlowCalculator():
    def __init__(self, cb=None): self.cb,self.res = cb,0
    
    def callback(self, cb_name, *args):
        if not self.cb: return
        cb = getattr(self.cb,cb_name, None)
        if cb: return cb(self, *args)

    def calc(self):
        for i in range(5):
            self.callback('before_calc', i)
            self.res += i*i
            sleep(1)
            if self.callback('after_calc', i):
                print("stopping early")
                break

class ModifyingCallback():
    def after_calc (self, calc, epoch):
        print(f"After {epoch}: {calc.res}")
        if calc.res>10: return True
        if calc.res<3: calc.res = calc.res*2

calculator = SlowCalculator(ModifyingCallback())

calculator.calc()
calculator.res

class SloppyAdder():
    def __init__(self,o): self.o=o
    def __add__(self,b): return SloppyAdder(self.o + b.o + 0.01)
    def __repr__(self): return str(self.o)

a = SloppyAdder(1)
b = SloppyAdder(2)
a+b

class A:
    a,b=1,2

a = A()

a.b

getattr(a, 'b' if random.random()>0.5 else 'a')

class B:
    a,b=1,2
    def __getattr__(self, k):
        if k[0]=='_': raise AttributeError(k)
        return f'Hello from {k}'

b = B()

b.foo