"""functools.py - Tools for working with functions and callable objects

"""

# Python module wrapper for _functools C module

# to allow utilities written in Python to be added

# to the functools module.

# Written by Nick Coghlan <ncoghlan at gmail.com>

#   Copyright (C) 2006 Python Software Foundation.

# See C source code for _functools credits/copyright

from _functools import partial

# update_wrapper() and wraps() are tools to help write

# wrapper functions that can handle naive introspection

WRAPPER_ASSIGNMENTS = ('__module__', '__name__', '__doc__')

WRAPPER_UPDATES = ('__dict__',)

def update_wrapper(wrapper,

                   wrapped,

                   assigned = WRAPPER_ASSIGNMENTS,

                   updated = WRAPPER_UPDATES):

    """Update a wrapper function to look like the wrapped function

       wrapper is the function to be updated

       wrapped is the original function

       assigned is a tuple naming the attributes assigned directly

       from the wrapped function to the wrapper function (defaults to

       functools.WRAPPER_ASSIGNMENTS)

       updated is a tuple naming the attributes off the wrapper that

       are updated with the corresponding attribute from the wrapped

       function (defaults to functools.WRAPPER_UPDATES)

    """

    for attr in assigned:

        setattr(wrapper, attr, getattr(wrapped, attr))

    for attr in updated:

        getattr(wrapper, attr).update(getattr(wrapped, attr, {}))

    # Return the wrapper so this can be used as a decorator via partial()

    return wrapper

def wraps(wrapped,

          assigned = WRAPPER_ASSIGNMENTS,

          updated = WRAPPER_UPDATES):

    """Decorator factory to apply update_wrapper() to a wrapper function

       Returns a decorator that invokes update_wrapper() with the decorated

       function as the wrapper argument and the arguments to wraps() as the

       remaining arguments. Default arguments are as for update_wrapper().

       This is a convenience function to simplify applying partial() to

       update_wrapper().

    """

    return partial(update_wrapper, wrapped=wrapped,

                   assigned=assigned, updated=updated)