I heard somebody say their language has a convention where the names of functions which mutate state must end with an exclamation point. I'm trying to write more functional code and I like the idea of somehow marking functions according to their side effect status i.e. none, inward side effects, outward side effects (I'm ignorant of the right fp terminology but you get the idea I hope).
Obviously it's easy for me to come up with my own naming scheme but I was wondering if such schemes/conventions already exist before I go and homebake one.
edit2: As for the mods closing this as primarily opinion based I have to disagree. I was asking what, if any, conventions were in common use - this is by anyone's definition a question of fact not opinion!