use strict;
use warnings;

use Benchmark qw( cmpthese );

my %cache;
sub memoized {
    my $left  = ( $cache{$a} ||= substr($a, -(19+20), 19) );
    my $right = ( $cache{$b} ||= substr($b, -(19+20), 19) );
    return $left cmp $right;
}

@::LogFileList if 0;
@::LogFileList = qw(
/devLog/devid234/term_logs/devid234.2009-08-27-23-55-11.terminal.log.tar.gz
/devLog/devid234/term_logs/devid234.2009-08-27-15-05-06.terminal.log.tar.gz
/devLog/devid234/term_logs/devid234.2009-08-27-01-45-03.terminal.log.tar.gz
/devLog/devid234/term_logs/devid234.2009-08-28-00-00-01.terminal.log.tar.gz
/devLog/devid234/term_logs/devid234.2009-08-28-18-25-04.terminal.log.tar.gz
/devLog/devid168/term_logs/devid168.2009-08-28-01-35-02.terminal.log.tar.gz
/devLog/devid168/term_logs/devid168.2009-08-27-04-02-01.terminal.log.tar.gz
/devLog/devid168/term_logs/devid168.2009-08-28-20-25-01.terminal.log.tar.gz
/devLog/devid168/term_logs/devid168.2009-08-27-17-55-01.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-27-21-15-01.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-27-13-25-01.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-27-00-00-01.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-28-00-00-02.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-28-09-45-01.terminal.log.tar.gz
/devLog/devid918/term_logs/devid918.2009-08-28-19-25-01.terminal.log.tar.gz
/devLog/devid167/term_logs/devid167.2009-08-28-02-45-01.terminal.log.tar.gz
/devLog/devid167/term_logs/devid167.2009-08-27-01-45-02.terminal.log.tar.gz
/devLog/devid167/term_logs/devid167.2009-08-27-10-55-01.terminal.log.tar.gz
);

cmpthese(-3, {
    naive => '
        use strict; use warnings;
        my @sorted =
            sort {
                substr($a, -(19+20), 19)
                   cmp
                substr($b, -(19+20), 19)
            }
            @::LogFileList;
    ',

    memoized => '
        use strict; use warnings;
        my @sorted = sort memoized @::LogFileList;
    ',

    st => '
        use strict; use warnings;
        my @sorted =
            map $_->[0],
            sort { $a->[1] cmp $b->[1] }
            map [ $_, substr($_, -(19+20), 19) ],
            @::LogFileList;
    ',

    grt => '
        use strict; use warnings;
        my @sorted =
            map substr($_, 19),
            sort
            map substr($_, -(19+20), 19) . $_,
            @::LogFileList;
    ',
});