my $retn = $alpha_a cmp $alpha_b;
    return $retn if $retn != 0;
    
    $retn = $num1_a <=> $num1_b;
    return $retn if $retn != 0;
    
    return $num2_a <=> $num2_b;
[download]

That can be compacter written as:

return $alpha_a cmp $alpha_b
      || $num1_a <=> $num1_b
      || $num2_a <=> $num2_b;
[download]