module type External =sig
..end
Structure.Open
from an Structure.Internal
datatype.
When a generic datatype is a combination of several other datatypes, these
functions allow interacting with its subparts. Note that their behavior is
undefined if the overall datatype contains several times the same datatype.type
t
type 'a
key
val mem : 'a key -> bool
val get : 'a key -> (t -> 'a) option
val set : 'a key ->
'a -> t -> t