implicities_of_python.py

#!/usr/bin/env python
# Added by Chaobin Tang <cbtchn@gmail.com>

'''
This module shows two very simple implicities
of Python
'''
import doctest


def count(a, elems=[]):
    '''
    >>> count(1)
    1
    >>> count(2)
    1
    >>> count(3)
    1
    '''
    elems.append(a)
    print len(elems)

def retry(func=None, exceptions=(Exception,), reruns=3):
    '''
    >>> def f(): a+b
    >>> f = retry(exceptions=(NameError))(f)
    >>> f()
    '''
    def decorator(func):
        def wrapped(*args, **kwargs):
            while reruns > 0:
                try:
                    return func(*args, **kwargs)
                except exceptions:
                    if reruns == 1:
                        raise Exception('Tried %s times' % reruns)
                    reruns -= 1
        return wrapped

    return decorator if (func is None) else decorator(func)

def main():
    doctest.testmod()

if __name__ == '__main__':
    main()