Complex Sort - using varying numbers of parameters

George_Sherston has asked for the wisdom of the Perl Monks concerning the following question:

I have an array of hashes, @Tree. One of the elements in each hash, Path is itself an array of digits. For each element in @Tree, $_->{Path} can have from one to five (at present - could be even more) elements. And I need to sort @Tree so that it's sorted first by $_->{Path}->[0], then by $_->{Path}->[1] and so on.

In case that doesn't make any sense, I've done

    for my $h (@Tree) {
        print "$_ " for @{$h->{Path}};
        print "\n";
    }
[download]

... for before and after, to show what I'm trying to achieve:

BEFORE

5 32 37
5 32 38
5 32 39
3 12 11 19 20
3 12 11 21
3 12 22
3 12 23
5 32 40
3 12 24
5 32 41
3 25
5 32 42
2 26
5 32 43
2 26 27
2 26 28
2 26 29
0 1
1 2
1 3
3 12 10
1 4
3 12 11
1 5
3 12
2 6
3 12 13
3 12 7
3 12 11 19 14
3 12 8
2 26 30
3 12 11 19 15
3 12 9
5 32 31
3 12 11 19 16
5 32
3 12 11 19 17
5 32 33
3 12 11 19 18
5 32 34
3 12 11 19
5 32 35
5 32 36
[download]

AFTER:

0 
1 2 
1 3 
1 4 
1 5 
2 6 
2 26 
2 26 27 
2 26 28 
2 26 29 
2 26 30 
3 12 
3 12 7 
3 12 8 
3 12 9 
3 12 10 
3 12 11 
3 12 11 19 
3 12 11 19 14 
3 12 11 19 15 
3 12 11 19 16 
3 12 11 19 17 
3 12 11 19 18 
3 12 11 19 20 
3 12 11 21 
3 12 13 
3 12 22 
3 12 23 
3 12 24 
3 25 
5 32 
5 32 31 
5 32 33 
5 32 34 
5 32 35 
5 32 36 
5 32 37 
5 32 38 
5 32 39 
5 32 40 
5 32 41 
5 32 42 
5 32 43
[download]

I've tried lots of different variations on

    for (5..0) {
        @Tree = sort {
        $a->{Path}->[$_] <=> $b->{Path}->[$_]
    } @Tree;
    }
[download]

... none of which worked. In the end I gave up in disgust and did

    for my $page (@Tree) {
        my $Sort = 0;
        my $M = 100;
        for (@{$page->{Path}}) {
            $Sort += $M * $_;
            $M = $M / 100;
        }
        $page->{Sort} = $Sort;
    }

    @Tree = sort {$a->{Sort} <=> $b->{Sort}} @Tree;
[download]

... which works, but is UGLY and probably slow and fattening. I'd really love to see a more elegant solution, if some monk can suggest one. Now, I got this result with the following rather clunky method:

§ George Sherston

2002-07-06 Edit by Corion: Added readmore tag

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