(?x)         # extended syntax
(?=.*[A-Z])  # look ahead for at least one upper case
(?=.*[a-z])  # look ahead for at least one lower case
(?=.*[0-9])  # look ahead for at least one numeral
(?=.*[~!@#$%\^&*()\-_=+\|\[{\]};:'",<.>/?])
             # look ahead for at least one of the listed symbols

{
$[ = 1 ;
}
print $[ ;

{
no warnings 'deprecated' ;
$[ = 1 ;
}

{
    use arybase ();
    BEGIN {
        $^H{'$['} = '1';
    }
    ($arybase::leftbrack = 1);
}
print($[);

mac(tchrist)% perl -X -le '$[ = 42; @a = ("many"); print $#a'
42

mac(tchrist)% perl -X -le '$[ = 42; $a[++$#a] = "many"; print $#a'
42

mac(tchrist)% perl -X -le '$[ = 42; $a[++$#a] = "many" for 1..5; print $#a'
46

mac(tchrist)% perl -X -le '$[ = -42; $a[++$#a] = "many" for 1..17; print $#a'
-26

mac(tchrist)% perl -X -le '$[ = -42; $a[--$#a] = "many" for 1..17; print $#a'
Modification of non-creatable array value attempted, subscript -43 at -e line 1.
Exit 2

my $deprecated = warnings::enabled( "deprecated" ) ;
no warnings 'deprecated' ;
$[ = 1 ;
use warnings 'deprecated' if $deprecated ;

Um