thanks, seriously. i couldn't get my head around the right-most map ...

Oh. You need to sort by value instead of asciibetically. I hate those sorts. You have to create a hash for lookup. Something like:

my %lookup = do {
    my $i = 1;
    map { $_ => $i++ } qw( S M L XL );
};
my @sorted_values =
    map {
        $_->[0]
    } sort {
        $a->[2] cmp $b->[2]
            ||
        $lookup{$a->[1]} <=> $lookup{$b->[1]}
    } map {
        my ($x, $y) = /\w+:\s(\w+),\s\w+:\s(\w+)/;
        [ $_, $x, $y ]
    } @strings;
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------
We are the carpenters and bricklayers of the Information Age.

Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose

You made the same mistake I did. That's not a Schwartzian Transform (or at least not a proper one). The hash lookup should only be performed once per item being sorted, so we should be tossing the lookup within the first map being performed, rather than within the sort. Not to mention your sort is off now as you are sorting first by color then by size, when the OP wanted size then color. So we should really have something like this:

#!c:/perl/bib/perl -w
$|++;

use strict;

my %map = (
   S => 0, M => 1, L => 2, Xl => 3
);

my @sorted = 
   map { $_->[0] } sort {
      $a->[1] <=> $b->[1] or
      $a->[2] cmp $b->[2]
   } map {
      /^(\w+:\s+(\w+),\s+\w+:\s+(\w+))$/ ?
         [$1, $map{$2}, $3] : ()
   } <DATA>;

print join("\n", @sorted);

__DATA__
size: L, color: White
size: M, color: Orange
size: M, color: White
size: M, color: White
size: S, color: Orange
size: S, color: White
size: Xl, color: Orange
size: Xl, color: White
size: Xl, color: White
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