functools_wraps.py

#!/usr/bin/env python


import functools


def show_details(name, f):
    """Show details of a callable object."""
    print '%s:' % name
    print ' object:', f
    print ' __name__:',
    try:
        print f.__name__
    except AttributeError:
        print '(no __name__)'
    print ' __doc__', repr(f.__doc__)
    print
    return


def simple_decorator(f):
    @functools.wraps(f)
    def decorated(a='decorated defaults', b=1):
        print ' decorated:', (a, b)
        print ' ',
        f(a, b=b)
        return
    return decorated


def myfunc(a, b=2):
    "myfunc() is not complicated"
    print ' myfunc:', (a, b)
    return

# The raw function
show_details('myfunc', myfunc)
myfunc('unwrapped, default b')
myfunc('unwrapped, passing b', 3)
print

# Wrap explicitly
wrapped_myfunc = simple_decorator(myfunc)
show_details('wrapped_myfunc', wrapped_myfunc)
wrapped_myfunc()
wrapped_myfunc('args to wrapped', 4)
print


# Wrap with decorator syntax
@simple_decorator
def decorated_myfunc(a, b):
    myfunc(a, b)
    return

show_details('decorated_myfunc', decorated_myfunc)
decorated_myfunc()
decorated_myfunc('args to decorated', 4)