That's not what idempotent means. Idempotent means forall x, f(x)=f(f(x)). Most pure functions are not idempotent. Heck, f(f(x)) doesn't even type-check for mos

That's not what idempotent means. Idempotent means forall x, f(x)=f(f(x)). Most pure functions are not idempotent. Heck, f(f(x)) doesn't even type-check for most f. The typical name given to always getting the same results is just "pure". It doesn't depend on any implicit state anywhere.