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From: Jacques Garrigue <garrigue@math.nagoya-u.ac.jp>
To: Gregory Malecha <gmalecha@gmail.com>
Cc: Mailing List OCaml <caml-list@inria.fr>
Subject: Re: [Caml-list] "Type constructor b would escape its scope"
Date: Mon, 28 Mar 2016 10:12:41 +0900	[thread overview]
Message-ID: <2D2C7D68-D59A-407B-B83A-65622DF9CC25@math.nagoya-u.ac.jp> (raw)
In-Reply-To: <CAGraiHJ=j_YtaKttyrZaXunc=1xuFBGZw20rOv1s+sAHwxqsOg@mail.gmail.com>

On 2016/03/28 03:52, Gregory Malecha wrote:
> 
> Thanks, Leo --
> 
> This is exactly what I needed to know. I thought that the (type a) annotation was forcing the function to be polymorphic. For future reference, is there any way to write the annotation (that forces the function to be polymorphic) without having to write explicit ‘fun's?

You should either write

  let generic_search_stream : ‘b. int option -> (internal_result, ‘b) result_stream = …

or
 
  let generic_search_stream : type b. int option -> (internal_result, b) result_stream = …

where the latter one both requires polymorphism and defines a locally abstract type,
i.e. probably the behavior you expect with (type b).

Jacques


  reply	other threads:[~2016-03-28  1:12 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-27  6:19 Gregory Malecha
2016-03-27  7:04 ` Leo White
2016-03-27 18:52   ` Gregory Malecha
2016-03-28  1:12     ` Jacques Garrigue [this message]
2016-03-28  4:20       ` Gregory Malecha
2016-03-28  8:07         ` Gabriel Scherer
2016-03-28 15:35           ` Gregory Malecha
2016-03-28 19:20           ` Arnaud Spiwack
2016-03-28 20:51             ` Leo White
2016-03-28 21:00             ` Gerd Stolpmann

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