A map.

Keys in t.

Values in t.

empty cap is an empty map with capacity cap.

• raises Invalid_argument

  when cap < 0.

is_empty t is true iff there are no bindings in t.

size t is the number of bindings in t.

weight t is the combined weight of bindings in t.

capacity t is the maximum combined weight of bindings that trim will retain.

resize cap t sets t's capacity to cap, while leaving the bindings unchanged.

• raises Invalid_argument

  when cap < 0.

trim t is t', where weight t' <= capacity t'.

This is achieved by discarding bindings in LRU-to-MRU order.

mem k t is true iff k is bound in t.

find k t is Some v when k -> v is bound in t, or None otherwise.

promote k t is t with the binding for k promoted to most-recently-used, or t if k is not bound in t.

add k v t adds the binding k -> v to t as the most-recently-used binding.

Note add does not remove bindings. To ensure that the resulting map is not over capacity, compose with trim.

remove k t is t without a binding for k.

pop k t is (v, t'), where v is the value bound to k, and t' is t without the binding k -> t, or None if k is not bound in t.

lru t is the least-recently-used binding in t, or None, when t is empty.

drop_lru t is t without the binding lru t, or t, when t is empty.

pop_lru t is ((k, v), t', where (k, v) is lru t, and t' is t without that binding.

fold f z t is f k0 v0 (... (f kn vn z)), where k0 -> v0 is LRU and kn -> vn is MRU.

fold_k f z t folds in key-increasing order, ignoring the recently-used ordering.

Note fold_k is faster than fold.

iter f t applies f to all the bindings in t in in LRU-to-MRU order.

iter_k f t applies f in key-increasing order, ignoring the recently-used ordering.

Note iter_k is faster than iter.

of_list kvs is a map with bindings kvs, where the order of the list becomes LRU-to-MRU ordering, and its capacity is set to its weight.

The resulting t has the same shape as if the bindings were sequentially added in list order, except for capacity.

to_list t are the bindings in t in LRU-to-MRU order.

pp ~pp_size ~sep pp_kv ppf t pretty-prints t to ppf, using pp_kv to print the bindings, ~sep to separate them, and ~pp_size to print the weight and capacity. ~sep and ~pp_size default to unspecified printers.