I need to sort a bunch of path names and wanted to use Sort::Key because I'm already using it several other places in my code. A proper path sorting algorithm requires splitting the path into its components for comparison, and the number of components can be arbitrary. All of the documentation for Sort::Key and its family of other modules assume the number of comparison keys is known. Is it possible to use Sort::Key for this use case and if so, how? Thanks.

Below is the script I am using for testing other sort routines: 

use List::Util qw(min);

my @path = qw(
    /abc
    /abc/1/2/a/b/c
    /abc/2
    /abc/def/1/2/a/b/c
    /abc!def/1/2/a/b/c
    /abc-def/1/2/a/b
    /abcdef/1/2/a/b/c
    /usr/a
);

say 'Wanted path order:';
say ' 'x4, $_ for @path;

my @sorted = sort @path;
say 'Lexical order (default sort):';
say ' 'x4, $_ for @sorted;

say 'Ordered by dirname, then basename:';
@sorted = map { $_->[0] }
    sort { $a->[1] cmp $b->[1] or $a->[2] cmp $b->[2] }
    map { [$_, m{^(.*/)?(.*)}s ] }
    @path;
say ' 'x4, $_ for @sorted;

say 'Ordered by path components:';
@sorted = sort bypath @path;
say ' 'x4, $_ for @sorted;

say 'Ordered by path components (with caching):';
@sorted = map { $_->[0] }
    sort {
        for my $i (0 .. min $#{$a->[1]}, $#{$b->[1]}) {
            return $a->[1][$i] cmp $b->[1][$i] if $a->[1][$i] ne $b->[
+1][$i];
        }
        return $#{$a->[1]} <=> $#{$b->[1]};
    }
    map { [$_, [split '/'] ] }
    @path;
say ' 'x4, $_ for @sorted;

exit;


# https://stackoverflow.com/questions/5124994/sorting-directory-filena
+mes-with-perl/19506331#19506331
sub bypath {
    my @a = split m'/', $a;
    my @b = split m'/', $b;
    for (my $i = 0; $i <= $#a; $i++) {
        last if $i > $#b;
        return $a[$i] cmp $b[$i] if $a[$i] cmp $b[$i];
    }
    return $#a <=> $#b;
}

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In reply to Sorting path names with Sort::Key by Anonymous Monk

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