From: Ivan Gotovchits <ivg@ieee.org>
To: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>
Cc: OCaML List Mailing <caml-list@inria.fr>
Subject: Re: [Caml-list] Request for feedback: A problem with injectivity and GADTs
Date: Mon, 29 Apr 2013 07:45:36 +0400 [thread overview]
Message-ID: <87a9oi9ezj.fsf@golf.niidar.ru> (raw)
In-Reply-To: <00C57DF0-C6F0-4EDE-8607-2155F3A17146@math.nagoya-u.ac.jp> (Jacques Garrigue's message of "Sun, 28 Apr 2013 09:02:56 +0900")
Jacques Garrigue <garrigue@math.nagoya-u.ac.jp> writes:
>
> If we need to be able to define GADTs relying on the injectivity of some abstract
> types, a straightforward solution is to add injectivity annotations on type parameters,
> the same way it was done for variance:
>
> type #'a t
>
I'm not sure that symbol '#' is a good choice. It is already used for
open types and may impose difficulties in undestanding code (and
compiler messages) when overriden. For me '#' is something polymorphic
and related to OOP.
And indeed, «#'a» is to perlish... Personally, I would prefer something
like:
type 'a t
constraint 'a is injective
P.S. the following symbols looks more «injective» for me: '>', '^', '=',
though the last one can be confused with the invariance.
--
(__)
(oo)
/------\/
/ | ||
* /\---/\
~~ ~~
...."Have you mooed today?"...
next prev parent reply other threads:[~2013-04-29 3:45 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-28 0:02 Jacques Garrigue
2013-04-28 2:45 ` Markus Mottl
2013-04-28 10:28 ` Jacques Garrigue
2013-04-28 5:54 ` Jacques Le Normand
2013-04-29 3:45 ` Ivan Gotovchits [this message]
2013-04-29 4:03 ` Ivan Gotovchits
2013-04-29 5:17 ` Jacques Le Normand
2013-04-29 7:58 ` Alain Frisch
2013-04-29 10:52 ` Jacques Garrigue
2013-04-29 11:23 ` Alain Frisch
2013-04-29 16:37 ` Nathan Mishra Linger
2013-04-29 23:53 ` Jacques Garrigue
2013-04-30 5:45 ` Jacques Garrigue
2013-05-04 6:46 ` Jacques Garrigue
2013-05-04 7:09 ` Gabriel Scherer
2013-05-04 12:28 ` Jacques Garrigue
2013-04-30 6:59 ` Alain Frisch
2013-04-30 7:56 ` Jacques Garrigue
2013-04-30 8:02 ` Alain Frisch
2013-04-30 8:18 ` Jacques Garrigue
2013-04-30 9:11 ` Gabriel Scherer
2013-04-30 9:55 ` Jacques Garrigue
2013-04-30 10:12 ` Leo White
2013-04-30 11:30 ` Gabriel Scherer
2013-04-30 13:06 ` Leo White
2013-04-29 7:59 ` Gabriel Scherer
2013-07-01 14:47 ` Alain Frisch
2013-07-01 23:20 ` Jacques Garrigue
2013-07-03 16:08 ` Alain Frisch
2013-07-03 16:13 ` Gabriel Scherer
2013-07-04 6:07 ` [Caml-list] Request for feedback: A problem with injectivity oleg
2013-07-04 7:35 ` Alain Frisch
2013-07-05 10:30 ` oleg
2013-07-05 12:02 ` Alain Frisch
2013-07-04 1:00 ` [Caml-list] Request for feedback: A problem with injectivity and GADTs Jacques Garrigue
2013-07-04 8:14 ` Alain Frisch
2013-07-04 8:52 ` Jacques Garrigue
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