As others have already pointed out qq() is basically the same as double quotes. But I wonder about that code you have there. The -1 argument to to index is ignored, so basically what that line is doing is: IF $input contains at least one space, then $key is set to the beginning of $input up to (but excluding) the first space. If, on the other hand, $input contains no spaces, then $key is set to $input minus its last character (or the empty string, if $input is empty); this is because in this case index returns -1, and therefore substr removes the last character.

It looks like pretty nutty code to me.