Observed-Remove set.
Supports add, remove, lookup and merge operations. See Immutable_types.RSet. Contains two separate instances of a regular Map, one for adding (add_s) and the other for removing (remove_s).
add el t adds (unique (), el) to add_s, where unique is the result of calling Random.bits. This may or may not be enough entropy for your use case.
remove el t adds all {(u, el) | ∃ u : (u, el) ∈ add_s} to remove_s
Both lookup and value operate on the set difference add_s \ remove_s.
merge a b calls merges add_s_a with add_s_b and the same for b
module Make
(O : Immutable_types.Comparable) :
Immutable_types.RSet with type elt = O.tCreates an add / remove set of elements satisfying Immutable_types.Comparable