package ringo

The type of values held by the cache.

The type of caches holding values of type elt.

create n creates a unit-cache with a size-bound of n. Remember that the size-bound is not upheld strictly by all caches.

add c v adds the value v to the cache c. This may or may not cause another element to be removed from the cache, depending on the number of elements already present in the cache c, the size-bound of the cache c, and the policy of the cache c towards its size-bound.

If v is already present in c, the element may count twice towards the size bound for some time. In other words: apart for size bound in some cases, the following sequences of operations are indistinguishable: add c v; add c u and add c v; remove c v; add c u

fold f c init folds the function f and value init over the elements of c.

Note that for caches with a Weak overflow policy, this function may fold over a subset of the elements of c. See Ringo (or Functors) for more details.

mem c v is true if v is present in c. It is false otherwise.

Note that the in caches with a non-FIFO replacement policy, this may have a side effect on the v element. Specifically, in those caches, it might make it less likely to be removed when supernumerary elements are inserted.

remove c v removes the element v from c. If v is not present in c, it does nothing.

Note that in caches with a Sloppy accounting policy, removed elements can still count towards the size bound for some time.

length c is the number of elements present in c.

capacity c is the number of bindings c can hold: capacity (create n) = n

clear c removes all elements from c.