Decorators

A simple guide to understanding how decorators in python work! This is for those who shall not decorate!

Decorators demystified

Most python programmers fear decorators. They are simply functions that wrap other functions and modify their behavior in the process.

For instance, if I want to run something before or/and after i execute my function, I can employ the use of decorators to do just that!

Code reusability and abstraction are among the benefits you will get from using decorators. Professional python programmers use decorators too. :-)

Requirements

For cloning, ensure you have installed Python 2.7+ No pip installs! Simple and easy. :-)

Quick Usage

You do not have to clone the repo. Just paste the code from decorators.py into a repl and click run. Magic happen at repl

Local usage

Run: python decorators.py

You can play around with the decorator-driven stopwatch by running: python stopwatch.py Feel free to include your own function to test how long it will take to execute.

Explanation

In python, functions can be passed into other functions. For example:

def func(pass_a_func):
    return pass_a_func()

Also, functions can wrap other functions.

def func():
    def wrapped_func():
       print "Long ago in a far distant land..."
    return wrapped_func

You can also return a function without calling it

def func(passed_in_func):
    def wrapped_function():
        print "Before the final blow was struck, I flung him into..."
        passed_in_func()
    # Return a function without calling it
    return wrapped_function

# Time for some experimentation
a = func()
print a # prints <function wrapped_function at (memory_location)>
print a() # prints "Before the final blow was struck, I flung him into..."

This means that: If you don't put parenthesis e.g wrapped_function(), a function can be passed around and can be assigned to other variables without executing it.