NAME Acme::Sort::Schwartzian - a keyword that provides sort via a Schwartzian transform SYNOPSIS use Acme::Sort::Schwarz sort_schwartz => { -as => 'ssort' }; my @sorted = ssort { length($_) } <=> qw(foobar baz quux xyzzy); print "$_\n" for @sorted; __END__ baz quux xyzzy foobar DESCRIPTION This module is mostly just for me to play with Parse::Keyword. In particular, it's a study of deparsing a coderef captured by Parse::Keyword and recompiling that into a block of a larger function (along with any closed over variables). This is a technique that might be useful in the future for something like Sub::Quote. It provides the keyword "sort_schwartz", but because that's annoying to type out, you can rename it something else (as shown in the SYNOPSIS). It implements the Schwartzian transform - i.e. something like this: my @sorted = map { $_->[0] } sort { $a->[1] cmp $b->[1] } map { [ $_ => func($_) ] } @unsorted; Keyword "sort_schwartz { KEY_BLOCK } OPERATOR? LIST" The key block is a block of Perl code that when given a value (in $_) generates a key to sort by. In other words, it's the "func()" in the bottom "map" of the standard Schwatzian transform. The operator is one of "cmp" (lexicographic), "-cmp" (reverse lexicographic), "<=>" (numeric) or "-<=>" (reverse numeric). If omitted, defaults to "cmp". The list is the list of items to be sorted. LIMITATIONS Currently closing over a variable in the key block doesn't work properly. You get a copy of the original data, and any modifications to it are not visible outside the key block. If that variable is a scalarref/arrayref/hashref, then you can safely mutate the structures pointed to by the reference. BUGS Please report any bugs to . SEE ALSO Sort::Key. AUTHOR Toby Inkster . COPYRIGHT AND LICENCE This software is copyright (c) 2013 by Toby Inkster. This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself. DISCLAIMER OF WARRANTIES THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.