returns how many times has ´f´ been called.

evaluate!(f,x)

Force (re-)evaluation of the cached function at x. Returns f(x) and stores the input value.

Evaluates the cached function at x. Returns f(x), it doesn' t store the input

returns the output cache stored in ´f´ Returns f(x), it doesn' t store the input. if your function has only one type cached, you can get the output cache without adding the type.