NAME

Sort::Half::Maker - Create half-sort subs easily

SYNOPSIS

    use Sort::Half::Maker qw(make_halfsort);

    $sub = make_halfsort( 
                  pre => [ qw(x y z) ],
                  post => [ qw(a b c) ],
                  any => sub { $_[0] cmp $_[1] },
    );
    @list = sort $sub qw(a y f h w z b t x);
    # qw(x y z f h t w a b)

DESCRIPTION

Before anything, what it a half-sort?

A half-sort is a sort subroutine defined by a starting list, an ending list and an ordinary sort subroutine. Elements in the starting list always go first in comparison to others and keep the original order. Elements in the ending list always go last in comparison to others and keep their original order. The remaining elements are sorted via the given ordinary sort subroutine.

An example, please?

Imagine we want to sort the list of key/value pairs of a hash, such that qw(name version abstract license author) come first and qw(meta-spec) comes last, using case-insensitive comparison in-between. With this module, this is done so:

    $sub = make_halfsort(
               pre => [ qw(name version abstract license author) ],
               post => [ qw(meta-spec) ],
               any => sub { lc $_[0] cmp lc $_[1] }
           );
    my @pairs = map { ($_, $h{$_}) } sort $sub keys(%h);

Why is it good for?

I don't see many uses for it. I played with the concept while writing a patch to improve META.yml generation by ExtUtils::MakeMaker. There we wanted to dump some keys (like name, version, abstract, license, author) before and then the ones the module author provided as extra information.

FUNCTIONS

make_halfsort

    $sub = make_halfsort(per => \@start, post => \@end, any => $sub);
    @sorted = sort $sub @unsorted;

SEE ALSO

Sort::Maker

BUGS

Please report bugs via CPAN RT http://rt.cpan.org/NoAuth/Bugs.html?Dist=Sort-Half-Maker.

AUTHOR

Adriano R. Ferreira, <ferreira@cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2007 by Adriano R. Ferreira

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