Re: [Caml-list] Expressing module sig and impl in mli file

[David House <dmhouse@gmail.com>]

The standard way of doing this is as follows (note that Identifier is
changing to Identifiable in the next version, so I'll use that
terminology):

module Bar : sig
  type t = string
  include Identifiable with type t := t
end

But if this is literally what you're doing, I'm sort of confused. The
point of identifiable is that you have explicit to_string/from_string
functions and the type equality with string is not exposed. E.g. you
might want to use a different comparison function than string
equality. If you expose the type equality with string, then people are
free to use String.compare on your type, so you don't get the
abstraction you wanted.