Session_7_Scopes_&_Closures

Session 8 - Scopes and Closures

Contents

• check_docstring
• generate_fibanoci
• function_counter
• function_counter_mod

check_docstring

def check_docstring(max_len) -> 'Function': 
    def docstring_fifty(func) -> 'bool':            
        result = len(func.__doc__) > max_len
        return result
    return docstring_fifty

• Checks if a given function has docstring more than max_len variable
• max_len is a free variable which can be checked with code.co_freevars function. its a test in testfile

generate_fibanoci

def generate_fibanoci() -> 'Function': 
    n = 0    
    def next_Fib() -> 'Integer' :
        a = 0
        b = 1
        c = 0
        nonlocal n    
        if (n==0):
            n = n + 1            
            return 0
        elif n==1:
            n = n + 1            
            return b 
        else:            
            for i in range(1,n):
                c = a + b
                a = b
                b = c 
            n = n + 1
            return b
    return next_Fib

• Fibnoci algorithm is fed at next_fib() closure function . n is a non local variable used as a counter to remember how many times a function(next_fib()) is called.

function_counter

def function_counter() -> 'Function':        
    count = dict()
    def inner(fn,*args, **kwargs) -> 'Function(*args, **kwargs)':           
        nonlocal count 
        count[fn.__name__] = count.get(fn.__name__, 0) + 1
        function_call_counter[fn.__name__] = count[fn.__name__] 
        return fn(*args, **kwargs)
    return inner

• A global dictionary 'function_call_counter' is used , count is sued to remmeber number of times each function is called. 'count' is used as a nonlocal variable that can used to reset if 'function_call_counter' is modified by some other function.

function_counter_mod

def function_counter_mod(user_dict) -> 'Function':
    def inner(fn, *args, **kwargs) -> 'Function':
        user_dict[fn.__name__] = user_dict.get(fn.__name__, 0) + 1
        return fn(*args, **kwargs)
    return inner 

• A user defined dictionary 'user_dict' is given as input and used , User provided dictionary is directly modified inside the function every time when a particular function is called.