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From: Lukasz Stafiniak <lukstafi@gmail.com>
To: Markus Mottl <markus.mottl@gmail.com>
Cc: OCaml List <caml-list@inria.fr>
Subject: Re: [Caml-list] Covariant GADTs
Date: Wed, 21 Sep 2016 12:14:31 +0200	[thread overview]
Message-ID: <CAJMfKEXxARn4cb7OFP5xNk6rpDx5nd45MW8UjKAf2q_rXBwEoA@mail.gmail.com> (raw)
In-Reply-To: <CAJMfKEVjEU9h+jEE9CbCQytfYoc8SOCpikDcBzouk+yUU8w2Og@mail.gmail.com>

On Wed, Sep 21, 2016 at 12:11 PM, Lukasz Stafiniak <lukstafi@gmail.com> wrote:
>
> A simple solution would be to "A-transform" (IIRC the term) accesses

Sorry, I forgot to define this. I mean rewrite rules like:
[f r.x] ==> [let x = r.x in f x]
where subsequently the existential variable is introduced (unpacked)
at the let-binding level. This corresponds to a single-variant GADT
pattern match.

> to fields with existential type variables. This would give a more
> narrow scope on the expression level than you suggest, but a
> well-defined one prior to type inference. To broaden the scope you
> would need to let-bind the field access yourself at the appropriate
> level.

  reply	other threads:[~2016-09-21 10:14 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-17 17:38 Markus Mottl
2016-09-18  8:17 ` Petter A. Urkedal
2016-09-19  1:52   ` Markus Mottl
2016-09-19  8:58     ` octachron
2016-09-19 10:18       ` Mikhail Mandrykin
2016-09-19 13:37         ` Mikhail Mandrykin
2016-09-19 14:46         ` Markus Mottl
2016-09-19 14:53           ` Mikhail Mandrykin
2016-09-19 15:03             ` Markus Mottl
2016-09-20 21:07               ` Markus Mottl
2016-09-21 10:11                 ` Lukasz Stafiniak
2016-09-21 10:14                   ` Lukasz Stafiniak [this message]
2016-09-21 17:04                     ` Markus Mottl
2016-09-21 21:40                       ` Gabriel Scherer
2016-09-22  0:39                         ` Markus Mottl
2016-09-24  5:09                           ` Yaron Minsky
2016-10-04 10:33                 ` Jacques Garrigue
2016-09-19 14:39       ` Markus Mottl
2016-09-19 10:05     ` Goswin von Brederlow

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