From: Dan Schmidt <dfan@dfan.org>
To: caml-list@inria.fr
Subject: Re: [Caml-list] polymorphic variant question
Date: 29 Aug 2002 12:41:27 -0400 [thread overview]
Message-ID: <u1y8hehxk.fsf@dfan.thecia.net> (raw)
In-Reply-To: <3D6E45DA.51D99F9F@noos.fr>
nadji@noos.fr writes:
| Hi all,
|
| I am puzzled by the code below which doesn't work.
|
| # let f = function `B -> ();;
| val f : [ `B] -> unit = <fun>
| # let g x = match (x:[`A|`B]) with `A -> () | y -> f y;;
| Characters 51-52:
| let g x = match (x:[`A|`B]) with `A -> () | y -> f y;;
| ^
| This expression has type [ `A | `B] but is here used with type [ `B]
| (denoting the "y" from the "f y")
|
| How can I say to OCaml that "y" can't be of type `A ?
Try
# let g x = match (x:[`A|`B]) with `A -> () | `B as y -> f y;;
Dan
--
http://www.dfan.org
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next prev parent reply other threads:[~2002-08-29 17:57 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-29 16:03 nadji
2002-08-29 16:41 ` Dan Schmidt [this message]
2002-08-29 17:16 ` Remi VANICAT
2002-08-29 19:05 ` nadji
-- strict thread matches above, loose matches on Subject: below --
2001-09-21 0:14 Charles Martin
2001-09-21 6:28 ` Francois Pottier
2001-09-21 8:39 ` Andreas Rossberg
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