Sorry, maybe I just don't get it, but why is your first example a stable sort? 
my @unsorted = 
  ([1,1], [2,1], [1,2], [2,2], [2,3], [1,3], [2,4], [1,4]);

print join( ' ', 
  map { $_->[0].$_->[1] } 
    sort { $a->[0] <=> $b->[0] } @unsorted) . "\n";

my @sortedindices = sort 
  { $unsorted[$a]->[0] <=> $unsorted[$b]->[0] } 
  0..$#unsorted;

print join ( ' ', map { $_->[0].$_->[1] } 
  @unsorted[@sortedindices]);
__END__
11 12 13 14 23 21 24 22
11 12 13 14 23 21 24 22

[download]
Both sorts are not stable.

daniel.

update: got it now ;-) replace compare-function by 
$unsorted[$a]->[0] <=> $unsorted[$b]->[0] || $a <=> $b

[download]

In reply to Re: Re: Stable sorting in Perl (old) by wirrwarr
in thread Stable sorting in Perl by sweetblood

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.