# Add Function Example with Optional Debugger
# Python 3 Reflexive Metaprogramming
# H. Conrad Cunningham

# Developed for CSci 658, Software Language Engineering, Spring 2018

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# 2018-03-24: (V1) debug decorator adapted from Beazley's 2013
#             Metaprogramming tutorial

from functools import wraps 
import os
	
def debug(func):
    if 'DEBUG' not in os.environ:
        return func
    msg = func.__qualname__
    @wraps(func)
    def wrapper(*args, **kwargs):
        print(msg)
        return func(*args, **kwargs)
    return wrapper

@debug
def add(x,y):
    'Adds x and y'
    return x + y

if __name__ == '__main__':
    print(f'add(2,5) = {add(2,5)}')
    print(f'add.__qualname__ = {add.__qualname__}')
    print(f'add.__doc__ = {add.__doc__}')