Std.Opaque
Opaque type is like regular type, except that we can print or examine it in any way. So it can't be serialized or pretty-printed. An Opaque.Make can create an instances of such type.
Opaque.Make
module type S = sig ... end
Opaque type is like regular type, except that we can print or examine it in any way. So it can't be serialized or pretty-printed.
module Make (M : sig ... end) : S with type t := M.t
creates a module implementing Opaque interface.
Opaque