A beautiful demo of Callback in Python.Do visualize in PythonTutor Visualize

pythonCallbackDemo.py

def sqrt(x, guess=0.1):
    print("Trying:", guess, "-- Value:", guess*guess)
    if good_enough(guess, x):
        return guess
    
    else:
        guess = improve_guess(guess, x)
        return sqrt(x, guess)

def good_enough(guess, x):
    if abs(guess * guess - x) < 1:
        return True
    else:
        return False
        
def avg(a, b):
    return (a + b) / 2.0

def improve_guess(guess, x):
    return avg(guess, float(x)/guess)
    
    
def sqrt(x, is_ge=good_enough, guess=0.1):
    print("Trying:", guess, "-- Value:", guess*guess)
    if is_ge(guess, x):
        return guess
    else:
        guess = improve_guess(guess, x)
        return sqrt(x, is_ge, guess)
        
        

# By the nuclear reactor people
def very_accurate_good_enough(guess, x):
    return abs(guess * guess - x) < 0.000000001
    
    
sqrt(36, is_ge=very_accurate_good_enough)