keen/col/mut-index-set

Source
mut-index-set record mut (has private fields)
Set of nats. This takes up space proportional to the largest value. This is ideal for a reasonably dense (at least 1/32 full) set of small numbers.
list-new mut-index-set(a nat32[])
new-with-capacity mut-index-set(capacity nat32)
capacity is 1 more than the greatest value that it can store without reallocating.
any bool(a mut-index-set)
size nat32(a mut-index-set)
This is O(n) (but pretty fast) where n is the largest value in a.
to nat32[](a mut-index-set)
subscript bool(a mut-index-set, n nat32)
~= void(a mut-index-set, n nat32)
try-add bool(a mut-index-set, n nat32)
-= void(a mut-index-set, n nat32)
some bool(a mut-index-set, f bool mut(nat32))