use String::Approx 'amatch';
use re 'eval';
use re 'debug';

$r = qr/((?:@{[ ramatch( 'APT' ) ]}\s)?\w+\d)$/;
$apt = ( "5678 DELAWARE AVENUE AOT 123" =~ $r )[0];

$\ = "\n";
print "\$apt=$apt";

sub ramatch {
    my $match = shift;
    my $match_len = length $match;
    $match =~ s(\\)(\\\\)g;
    $match =~ s(')(\\')g;
    return
        "(?x:\Q$match\E |
             (?(?{scalar amatch('$match',substr(\$_,pos(),$match_len))})
               (?s:@{[ q[.] x $match_len]}) |
               (?!)))";
}