I wouldn't make a Rock-Paper-Lizard-Spock set of rules for this; I'd let the narrative define limits and permission as the game progresses.
Not least because I wouldn't want to make an exhaustive list of weapons and their interrelations.
I might, however, make a template for designing a weapon skill.
> Can your weapon defend against attacks? If so, choose whether you can use this skill to defend against quick, darting attacks or heavy, slow attacks.
Again, I need to get PayPal working because the Atomic Robo point-buy system for designing skills seems really useful here.