This is rather ridiculously easy, actually:

use strict;
use warnings;

comb('',[1..10],['a'..'c'],['x'..'z']);

sub comb {
    if ($#{@_} == 1) { print "$_[0]$_\n" for @{$_[1]}; }
    else { comb($_[0].$_, @_[2..$#{@_}]) for @{$_[1]}; }
}
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