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From: Jeremy Yallop <yallop@gmail.com>
To: Andreas Rossberg <rossberg@mpi-sws.org>
Cc: Gabriel Scherer <gabriel.scherer@gmail.com>, Alain Frisch <alain.frisch@lexifi.com>,  caml users <caml-list@inria.fr>
Subject: Re: [Caml-list] Newbie comment on constructor syntax
Date: Mon, 9 Nov 2015 22:57:31 +0000
Message-ID: <CAAxsn=FfxeGReM2T_c3y7JEkr5t4VuX+EF7eoepnh97y943+wA@mail.gmail.com> (raw)
In-Reply-To: <95AE93FB-4D5A-43E2-B72F-40C348403AA6@mpi-sws.org>

On 9 November 2015 at 22:27, Andreas Rossberg <rossberg@mpi-sws.org> wrote:
>> On Nov 9, 2015, at 22:11 , Gabriel Scherer <gabriel.scherer@gmail.com> wrote:
>> I like the revised syntax choice of writing
>>  type t = A of int and int list
>> instead of
>>  type t = A of int * int list
>> which removes the beginner surprise without introducing other
>> unpalatable design side-effects. (It is still awkward for GADTs, but
>> such is life.)
>
> I am not fond of the revised syntax, because it does not explain why the term-level syntax for constructor application uses tuple notation.

In fact, the revised syntax doesn't use tuple notation for constructor
application!  The revised type definition syntax also has a few
additional differences, such as prefix type constructor application,
besides the one Gabriel mentioned.  Here's an example, showing how to
define a data type with a multi-argument constructor and to construct
and match against values, with curried notation:

   # type t = [ A of int and list int ];
   type t = [ A of int and list int ]
   # value x = A 3 [];
   value x : t = A 3 []
   # fun [ A x y -> (x, y) ];
   - : t -> (int * list int) = <fun>

However, partial application of constructors is not supported:

   # A 3;
   Characters 0-3:
     A 3;
     ^^^
   Error: The constructor A expects 2 argument(s),
          but is applied here to 1 argument(s)


Jeremy.

  reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-06  9:33 Soegtrop, Michael
2015-11-06 10:04 ` Nicolas Ojeda Bar
2015-11-06 10:31 ` Francois Berenger
2015-11-06 12:20   ` Soegtrop, Michael
2015-11-06 12:34     ` Gabriel Scherer
2015-11-06 13:09       ` Soegtrop, Michael
2015-11-06 14:10         ` Ashish Agarwal
2015-11-06 15:19           ` Soegtrop, Michael
2015-11-06 15:22             ` Ashish Agarwal
2015-11-21 17:24       ` [Caml-list] Notation for currying Hendrik Boom
2015-11-21 17:42         ` Gabriel Scherer
2015-11-21 18:06         ` David Rajchenbach-Teller
2015-11-21 18:56           ` Gabriel Scherer
2015-11-06 12:29 ` [Caml-list] Newbie comment on constructor syntax Jonas Jensen
2015-11-06 12:46   ` Soegtrop, Michael
2015-11-06 12:55     ` Gabriel Scherer
2015-11-08 21:17 ` Florian Weimer
2015-11-08 22:51   ` Norman Hardy
2015-11-09  6:27     ` Florian Weimer
2015-11-09 13:27       ` Stefan Monnier
2015-11-09  8:10     ` Soegtrop, Michael
2015-11-09 10:00       ` Hendrik Boom
2015-11-09 10:17       ` Alain Frisch
2015-11-09 10:35         ` Andreas Rossberg
2015-11-09 12:28           ` Alain Frisch
2015-11-09 17:33           ` Alain Frisch
2015-11-09 18:09             ` Gabriel Scherer
2015-11-09 18:16               ` Andreas Rossberg
2015-11-09 21:12                 ` Gabriel Scherer
2015-11-09 22:06                   ` Alain Frisch
2015-11-09 22:27                   ` Andreas Rossberg
2015-11-09 22:57                     ` Jeremy Yallop [this message]
2015-11-10  0:11                   ` Hendrik Boom
2015-11-10  8:27                   ` Soegtrop, Michael
2015-11-10 10:26                     ` Romain Bardou
2015-11-10 10:44                       ` Alain Frisch
2015-11-10 10:55                         ` Romain Bardou
2015-11-10 13:17                           ` Alain Frisch
2015-11-10 13:41                             ` Romain Bardou
2015-11-10 14:01                               ` Alain Frisch
2015-11-13 15:36                           ` Romain Bardou
2015-11-10 11:17                         ` Soegtrop, Michael
2015-11-10 14:11                     ` Hendrik Boom
2015-11-10 14:40                       ` immanuel litzroth
2015-11-10 15:30                       ` Soegtrop, Michael
2015-11-10 17:28                         ` Gerd Stolpmann
2015-11-09 20:32               ` Alain Frisch

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