grap returns the element that matched, which may be 0 or some other false value. So you can't use this module to find out if 0 is a member of some array. _{(This is no longer true since you've edited your post.)}

You could use the prototype (&@) to make your grap easier to call.

By the way, your subroutine is not different from first() in List::Util. _{(This is no longer true, either.)}