NAME
    PerlIO::code - Makes a simple I/O filter

SYNOPSIS
            use PerlIO::code; # need to say explicitly

            # make an input filter
            open my $in, '<', sub{ uc scalar <> };
            print while <$in>;

            # make an output filter
            open my $out, '>', sub{ print uc shift };
            print $out while <>;

DESCRIPTION
    "PerlIO::code" helps to make an I/O filter. It is easier than "tie", but
    provides very limited functions. All it can do is to "readline" and
    "print".

NOTES
    *   For some reason, the actual layer name of "PerlIO::code" is ":Code",
        not ":code".

    *   "PerlIO::code" is slower than the "tie" interface.

    *   "open my $in, '<', sub{ "foo" }; my $s = <$in>;" makes an endless
        loop, because the internal "readline" routine reads $in on until
        reaching EOF.

CONFIGURATION AND ENVIRONMENT
    No configuration files or environment variables.

DEPENDENCIES
    Perl 5.8.1 or later, and a C compiler.

BUGS AND LIMITATIONS
    No bugs have been reported.

    Please report any bugs or feature requests to
    "bug-perlio-code@rt.cpan.org", or through the web interface at
    <http://rt.cpan.org/>.

SEE ALSO
    Tie::Handle.

    PerlIO::via.

    PerlIO.

AUTHOR
    Goro Fuji "<gfuji (at) cpan.org>"

LICENCE AND COPYRIGHT
    Copyright (c) 2008, Goro Fuji "<gfuji (at) cpan.org>". Some rights
    reserved.

    This module is free software; you can redistribute it and/or modify it
    under the same terms as Perl itself. See perlartistic.