I thought about this too, when writing my reply to Re: CPAN module fior common idioms?. But I did three distict different design choices. My sort call looks like this:

    my @foo = qw/
        a3
        b2
        r4
        s1
    /;

    print for STsort(
        sub { /(\d+)$/ },
        sub { $_[0][1] <=> $_[1][1] },
        @foo
    );

    __END__
    s1
    b2
    a3
    r4

[download]

• Order of the subs: I feel it's more natural to first see the transformation and then how that transformation should be sorted, as the sort sub means nothing if you haven't seen the transformation sub. An inlined ST is read backwards.
• $_[0] instead of $a: &STsort can't, without voodoo AFAIK, in every case realize which $a and $b to use.
• Original at index 0: I put the original value at the beginning of the array instead of at the end. I feel this is nicer when I don't know the length of the result of the transformation.

ihb

Read argumentation in its context!