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.

add 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 some caches, the old binding is erased but may still count 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 k v; add c k u and add c k v; remove c k; add c k u

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

Note that for some cache, this function may fold over a subset of the bindings of c. See Functors for more details.

iter f c iterates the function f over the bindings of c.

Note that for some cache, this function may iterate over a subset of the bindings of c. See Functors for more details.

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

Note that the in some caches, this may have a side effect on the k-to-v binding. Specifically, in some 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 some caches, removed bindings can still count towards the size bound for some time.

length c is the number of bindings held by c.

clear c removes all bindings from c.