The type of the hashtable keys.
The equality predicate used to compare keys.
A hashing function on keys. It must be such that if two keys are
equal according to
equal
, then they have identical hash values
as computed by
hash
.
Examples: suitable (
equal
,
hash
) pairs for arbitrary key
types include
(
(=)
,
Hashtbl.hash
) for comparing objects by structure,
(
(fun x y -> compare x y = 0)
,
Hashtbl.hash
)
for comparing objects by structure and handling
nan
correctly, and
(
(==)
,
Hashtbl.hash
) for comparing objects by addresses
(e.g. for cyclic keys).