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From: Romain Bardou <romain@cryptosense.com>
To: Alain Frisch <alain.frisch@lexifi.com>, caml-list@inria.fr
Subject: Re: [Caml-list] Newbie comment on constructor syntax
Date: Tue, 10 Nov 2015 11:55:15 +0100
Message-ID: <5641CD13.1080900@cryptosense.com> (raw)
In-Reply-To: <5641CA8E.4060909@lexifi.com>

On 10/11/2015 11:44, Alain Frisch wrote:
> On 10/11/2015 11:25, Romain Bardou wrote:
>> In the Mantis thread I proposed that #C or (C) would be the curried
>> version of constructor C.
>
> If we go in the direction of making n-ary constructors behave as
> constructor taking a tuple (at the expression level) then it seems
> confusing that #C would mean something different for:
>
>    type t = A of int * int
>
> and for:
>
>    type t = A of (int * int)
>
> Moreover, I'm not sure about the benefit:  how often do you need to
> partially apply a constructor?  And it's easy to define manually the
> helper function (let a x y = A (x, y)) if needed.  I don't think adding
> dedicated syntax is justified here.
>
> Andreas suggested that a non-constant unapplied constructor would be
> interpreted as a function (i.e. just A would be interpreted as (fun x ->
> A x)).  This would allow writing for instance "List.map Some l", and
> have the nice consequence that "Some e" becomes equivalent to "(Some)
> e".  The only drawback I can think of with this idea is less useful
> error locations when changing a constant constructor into a non-constant
> one.
>
> Alain
>

That #C would mean something different for the definitions is an issue 
with the syntax and the semantics of constructor definitions I believe, 
which is already rather confusing :)

That being said it's true that most of the time when I use a constructor 
as a function, the constructor has arity 1. In fact, most of the time it 
is Some.

Cheers,

-- 
Romain Bardou

  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
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 [this message]
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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