The functional module hasn't been maintained since 2006 and doesn't work with Python 3.

pitrou · pitrou · commit b53e2c4900d3 · 2011-12-05T01:05:55.000+01:00
Remove section about it from the functional programming FAQ.
diff --git a/Doc/howto/functional.rst b/Doc/howto/functional.rst
@@ -1010,135 +1010,6 @@ Some of the functions in this module are:
 Consult the operator module's documentation for a complete list.
 
 
-
-The functional module
----------------------
-
-Collin Winter's `functional module <http://oakwinter.com/code/functional/>`__
-provides a number of more advanced tools for functional programming. It also
-reimplements several Python built-ins, trying to make them more intuitive to
-those used to functional programming in other languages.
-
-This section contains an introduction to some of the most important functions in
-``functional``; full documentation can be found at `the project's website
-<http://oakwinter.com/code/functional/documentation/>`__.
-
-``compose(outer, inner, unpack=False)``
-
-The ``compose()`` function implements function composition.  In other words, it
-returns a wrapper around the ``outer`` and ``inner`` callables, such that the
-return value from ``inner`` is fed directly to ``outer``.  That is, ::
-
-    >>> def add(a, b):
-    ...     return a + b
-    ...
-    >>> def double(a):
-    ...     return 2 * a
-    ...
-    >>> compose(double, add)(5, 6)
-    22
-
-is equivalent to ::
-
-    >>> double(add(5, 6))
-    22
-
-The ``unpack`` keyword is provided to work around the fact that Python functions
-are not always `fully curried <http://en.wikipedia.org/wiki/Currying>`__.  By
-default, it is expected that the ``inner`` function will return a single object
-and that the ``outer`` function will take a single argument. Setting the
-``unpack`` argument causes ``compose`` to expect a tuple from ``inner`` which
-will be expanded before being passed to ``outer``. Put simply, ::
-
-    compose(f, g)(5, 6)
-
-is equivalent to::
-
-    f(g(5, 6))
-
-while ::
-
-    compose(f, g, unpack=True)(5, 6)
-
-is equivalent to::
-
-    f(*g(5, 6))
-
-Even though ``compose()`` only accepts two functions, it's trivial to build up a
-version that will compose any number of functions. We'll use
-:func:`functools.reduce`, ``compose()`` and ``partial()`` (the last of which is
-provided by both ``functional`` and ``functools``). ::
-
-    from functional import compose, partial
-    import functools
-
-
-    multi_compose = partial(functools.reduce, compose)
-
-
-We can also use ``map()``, ``compose()`` and ``partial()`` to craft a version of
-``"".join(...)`` that converts its arguments to string::
-
-    from functional import compose, partial
-
-    join = compose("".join, partial(map, str))
-
-
-``flip(func)``
-
-``flip()`` wraps the callable in ``func`` and causes it to receive its
-non-keyword arguments in reverse order. ::
-
-    >>> def triple(a, b, c):
-    ...     return (a, b, c)
-    ...
-    >>> triple(5, 6, 7)
-    (5, 6, 7)
-    >>>
-    >>> flipped_triple = flip(triple)
-    >>> flipped_triple(5, 6, 7)
-    (7, 6, 5)
-
-``foldl(func, start, iterable)``
-
-``foldl()`` takes a binary function, a starting value (usually some kind of
-'zero'), and an iterable.  The function is applied to the starting value and the
-first element of the list, then the result of that and the second element of the
-list, then the result of that and the third element of the list, and so on.
-
-This means that a call such as::
-
-    foldl(f, 0, [1, 2, 3])
-
-is equivalent to::
-
-    f(f(f(0, 1), 2), 3)
-
-
-``foldl()`` is roughly equivalent to the following recursive function::
-
-    def foldl(func, start, seq):
-        if len(seq) == 0:
-            return start
-
-        return foldl(func, func(start, seq[0]), seq[1:])
-
-Speaking of equivalence, the above ``foldl`` call can be expressed in terms of
-the built-in :func:`functools.reduce` like so::
-
-    import functools
-    functools.reduce(f, [1, 2, 3], 0)
-
-
-We can use ``foldl()``, ``operator.concat()`` and ``partial()`` to write a
-cleaner, more aesthetically-pleasing version of Python's ``"".join(...)``
-idiom::
-
-    from functional import foldl, partial from operator import concat
-
-    join = partial(foldl, concat, "")
-
-
 Small functions and the lambda expression
 =========================================
 
