From: Jean-Christophe Filliatre <Jean-Christophe.Filliatre@lri.fr>
To: Mike Hamburg <hamburg@fas.harvard.edu>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] 'a Set?
Date: Wed, 26 Jan 2005 09:25:56 +0100 [thread overview]
Message-ID: <16887.21524.707176.646417@gargle.gargle.HOWL> (raw)
In-Reply-To: <727068A7-6F2C-11D9-8411-0003939A19AA@fas.harvard.edu>
Mike Hamburg writes:
> Is there any clean way to make a type 'a set, corresponding to Set.Make
> of a module with type t='a and compare=Pervasives.compare? I'm trying
> to make a module which uses sets of arbitrary types of objects, and I
> don't want to have to make it a functor.
This is a recurrent question on this list.
> Is there a clean way to do this without removing the code from set.ml
> and modifying it?
Unfortunately, no.
Note that when duplicating the code from set.ml, you can either keep a
functorized code, with an additional type parameter:
module type OrderedType = sig
type 'a t
val compare: 'a t -> 'a t -> int
end
module type S = sig
type 'a elt
type 'a t
...
end
module Make(Ord: OrderedType): (S with type 'a elt = 'a Ord.t)
or directly substitute Pervasives.compare for the comparison function
to get a polymorphic data structure (and no functor anymore):
module AlphaSet : sig
type 'a elt
type 'a t
...
end
Best regards,
--
Jean-Christophe
next prev parent reply other threads:[~2005-01-26 8:25 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-01-25 23:54 Mike Hamburg
2005-01-26 8:25 ` Jean-Christophe Filliatre [this message]
2005-01-26 10:13 ` [Caml-list] " Frédéric Gava
2005-01-26 11:04 ` Radu Grigore
2005-01-26 12:04 ` Jacques Garrigue
2005-01-26 16:00 ` Alex Baretta
2005-01-26 16:14 ` Jacques Carette
2005-01-26 21:09 ` Mike Hamburg
2005-01-29 9:55 ` Radu Grigore
2005-01-26 9:13 ` Jon Harrop
2005-01-26 15:36 ` Frédéric Gava
2005-01-26 16:06 ` Jon Harrop
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