EmptyMap(H) is a map module but it only supports the empty map: a map with zero elements.
The create function ignores its size-limit parameter: the size limit is hardcoded.
Note that all policies are equivalent in the case of an empty map. This is why the empty map does not require the user to specify any policy.
A Mutable structure akin to a hash-table, but with a size bound. Note that, different caches have different policies towards the size bounds: some uphold the bound strictly, some treat the bound as a suggestion. In addition, some caches count their elements somewhat sloppily.
In general, the caches of Aches are intended to be used in settings that do not require strict, by-the-number, extremely-predictable behaviors.
See Vache (or Functors) for more information.
val create : int -> 'a tcreate 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 from newest to oldest.
Note that for caches with a Weak overflow policy, this function may fold over a subset of the bindings of c. See Vache (or Functors) for more details.
fold_oldest_first is like fold but in reversed order: oldest elements of c first. This function has the same limitation as fold.
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.
val length : 'a t -> intlength c is the number of bindings held by c.
val capacity : 'a t -> intcapacity c is the number of bindings c can hold: capacity (create n) = n
val clear : 'a t -> unitclear c removes all bindings from c.