Procedure Element: Item in Player's Hand

This request is fairly simple (at least to me, programming it may be basically impossible, I have no idea). For entity management, there are the procedure elements (I'm assuming that's what they're called) "Item in entity's main hand" and "Item in entity's off hand". As far as I can tell, these do not work if you are trying to refer to the item in the player's main or off hand. I think it would be very nice and helpful if "Item in player's main hand" and "Item in player's off hand" could be added. If there's a workaround to make something equivalent to this, please let me know. Otherwise, I would really like this to be added. Thank you! =)