Hi Zucan

If you want to sort alphabetically the words with the vowels at the same position, you can make just a very simple change to just one line of the original ST code suggested by choroba:

#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my @words = qw( fanfare apparate panacea parmesan albatross
                albacore false vermeil candelabra beans );

say for map $_->[0],
        sort { $a->[1] cmp $b->[1] || $a->[0] cmp $b->[0]}
        map [ $_, join q(), /[aeiou]/g ],
        @words;
[download]

For each time comparison step in the sorting algorithm, if the vowels compare equal, then

$a->[1] cmp $b->[1]
[download]

return 0. And it returns -1 or +1 in all the other cases. If you get a 0, then the logical or (||) will execute the second part of the sort statement:

$a->[0] cmp $b->[0]
[download]

to try to see if the whole expression is true. But if you get -1 or +1 with the first part, then the whole expression if already known to be true, so that the second part of the statement will not be executed (short-circuited).

I do not think that the other edge case you mention is compatible with the initial question.