The type of keys on which values in the cache are indexed.

The type of caches holding bindings from key to 'a

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

replace c k v binds the key k to the value v in the cache c. This may or may not cause another binding to be removed from the cache, depending on the number of bindings 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 k is already bound to a value in c, the previous binding disappears and is replaced by the new binding to v.

Note that in caches with a Sloppy accounting policy, the old (removed) binding may still count towards the size bound for some time.

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

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

fold_v f c init folds the function f and value init over the values held by the bindings of c.

It is less powerful than fold in that it does not grant access to the bindings' keys, but it does fold over all the values bound in c, even when the c has a Weak overflow policy.

find_opt c k is Some v if k is bound to v in c. It is None otherwise.

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

remove c k removes the binding from k in c. If k is not bound in c, it does nothing.

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

length c is the number of bindings held by c.

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

clear c removes all bindings from c.