Re: parameterized signatures

From: Markus Mottl (
Date: Thu Dec 23 1999 - 11:44:53 MET

From: Markus Mottl <>
Message-Id: <>
Subject: Re: parameterized signatures
To: (Chris Tilt)
Date: Thu, 23 Dec 1999 11:44:53 +0100 (MET)
In-Reply-To: <> from "Chris Tilt" at Dec 22, 99 11:32:25 am


> Is there a way to refer to the type of a functor defined by a .mli file
> in another .mli file?

> =====> the problem area. How do I express the type of this module?
> module type Wgraph = Pgraph.S ???

Acessing .mli-files as signatures is currently not possible. If I remember
right, I have already asked once whether this could be allowed, but I was
told that this would cause confusions about module names and module-type

Therefore, if I use functors I normally do not use an .mli-file to restrict
the interface, but split up the code in something like:

and restrict the modules/functors explicitely.

"" contains, for example:

  module type SPEC = sig ... end
  module type T = sig ... end

and "":

  open Foo_intf

  module Make (Spec : SPEC) : (T with ...) = struct ... end

Sometimes it is necessary to "reexport" types from the "specification"

Then I do this like:

  module Make (Spec_ : SPEC) : (T with ...) = struct
    module Spec = Spec_
    open Spec

Of course, the signature T will then have to include something like:

  module type SPEC = sig ... end

  module type T = sig
    module Spec : SPEC
    open Spec

and will thus make available all types in "Spec".

I hope this helps!

Best regards,
Markus Mottl

Markus Mottl,,

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