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From: Andreas Rossberg <rossberg@mpi-sws.org>
To: Markus Mottl <markus.mottl@gmail.com>
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Date: Mon, 9 May 2011 19:33:12 +0200
Cc: yminsky@gmail.com, caml-list@inria.fr
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Subject: Re: [Caml-list] "with module" surprises

On May 9, 2011, at 19.21 h, Markus Mottl wrote:
> A use case for the intended semantics might be reexporting of  
> functor arguments:
>
>  module Make (Arg : ARG) : S with module Spec = Arg = struct
>    module Spec = Arg
>    ...
>  end
>
> It could be bad from a design perspective to lose substructures in
> "Spec" which were unknown to "S".

If I understand your example correctly, then I don't think it does  
what you think it does. That is, if you apply Make to some M that is  
wider than ARG, you still won't have the additional components in  
F(M).Spec, because M gets narrowed to ARG by the functor application  
anyway.

/Andreas