@pointfree<EOL>def pffilter(pred, iterable):
for item in iterable:<EOL><INDENT>if pred(item): yield item<EOL><DEDENT>
Pointfree filter function.

    Example::

        >>> f = pffilter(lambda n: n % 2 == 0) \\
        ...     >> pfcollect

        >>> f(range(5))
        [0, 2, 4]