From: Yotam Barnoy <yotambarnoy@gmail.com>
To: Ocaml Mailing List <caml-list@inria.fr>
Subject: [Caml-list] Expanding functors
Date: Thu, 27 Aug 2015 09:29:54 -0400 [thread overview]
Message-ID: <CAN6ygOkt00dsKkZPvKybbeHa-yw_s7tKC2LwHPGcRPDCUBz51Q@mail.gmail.com> (raw)
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One problem I've commonly encountered in OCaml is the inability to expand
the interface of functors after they've been created (I'm not talking about
post-application). For example, Map.Make in the stdlib takes an OrderedType
module which contains only the compare function. What happens if I want to
add something to this interface, such as a show function? I have to copy
the whole implementation of Map.Make into my own file to modify it. Compare
this to the ability to 'include' a regular module and just add the new
functionality, and to take the type of a module and expand that type as
needed. Functors are severely lacking in this regard.
What do people think of this idea -- of allowing functors to be expanded?
Ideally, expanding a functor would allow for both replacing its argument
type (as in the example I gave) and for adding a second/third functor
argument type (so Map.Make(OrderedType) would become
Map.Make(OrderedType)(Show).
-Yotam
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next reply other threads:[~2015-08-27 13:30 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-27 13:29 Yotam Barnoy [this message]
2015-08-27 13:33 ` Drup
2015-08-27 13:35 ` Gabriel Scherer
2015-08-27 14:17 ` Yotam Barnoy
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