caml-list - the Caml user's mailing list
 help / Atom feed
From: Gabriel Scherer <gabriel.scherer@gmail.com>
To: Hendrik Boom <hendrik@topoi.pooq.com>
Cc: caml users <caml-list@inria.fr>
Subject: Re: [Caml-list] Notation for currying
Date: Sat, 21 Nov 2015 18:41:53 +0100
Message-ID: <CAPFanBHjPf41BS=NOSkT5Zh4m5AyYd8N-Knj1-Sa0vrpEkm7=g@mail.gmail.com> (raw)
In-Reply-To: <20151121172401.GA31756@topoi.pooq.com>

[-- Attachment #1: Type: text/plain, Size: 2526 bytes --]

In a previous life I would write Camlp4 extension for fun, and I used the
syntax
  \( ... _ ...)
to abstract over an anonymous variables (you could also use \1 \2 \3 etc,
and the n-th occurence of _ from left to right was turned into \n, but
mixing numbers and _ was disallowed). It solves Scala's problem that, the
scope of _ being delimited by the closest parentheses, the notation was not
composable -- but arguably enforcing a small scope is a good thing.

This is the kind of features that nobody will ever agree on, so it's too
hard to get them in a language. Nowadays I write "(fun x ->" instead of
"\(", and "x" instead of "_", and it is not that bad.

Arthur Charguéraud has been working on an "easy-type-errors" mode with
better typing error messages for OCaml. You may be interested in his article
  http://www.chargueraud.org/research/2015/ocaml_errors/ocaml_errors.pdf
although I think this specific case of under-application is not discussed
(using too many argument is discussed).

I also find the work on SHErrLoc, by Danfeng Zhang, Andrew C. Myers and
their collaborators, to be very impressive:
  http://www.cs.cornell.edu/Projects/SHErrLoc/

On Sat, Nov 21, 2015 at 6:24 PM, Hendrik Boom <hendrik@topoi.pooq.com>
wrote:

> On Fri, Nov 06, 2015 at 01:34:11PM +0100, Gabriel Scherer wrote:
> >
> > I personally believe that currified constructor syntax would be a better
> > choice, and that using non-currified constructors is a historical mistake
> > of SML/Caml. But I am also not convinced that efforts to change it today
> > are worth the trouble, and prefer to concentrate on improving other parts
> > of the OCaml ecosystem.
>
> Perhaps there should be explicit syntax for currying, such as
>    f a b _
> instead of
>    f a b
> That would permit currying in other argument positions:
>    f a _ c
> though I suspect _ may be the wrong symbol for the current language, and
> I also suspect it's far too late tointroduce it in the current language.
>
> I have noticed that almost a the situations where the compiler thinks I
> mean to curry I actually just left out a parameter by mistake.  The type
> inferences it makes based on these errors usually occur elsewhere and
> are truly mystifying.
>
> -- hendrik
>
> --
> Caml-list mailing list.  Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>

[-- Attachment #2: Type: text/html, Size: 3512 bytes --]

  reply index

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-06  9:33 [Caml-list] Newbie comment on constructor syntax 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 [this message]
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
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

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAPFanBHjPf41BS=NOSkT5Zh4m5AyYd8N-Knj1-Sa0vrpEkm7=g@mail.gmail.com' \
    --to=gabriel.scherer@gmail.com \
    --cc=caml-list@inria.fr \
    --cc=hendrik@topoi.pooq.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

caml-list - the Caml user's mailing list

Archives are clonable: git clone --mirror https://inbox.ocaml.org/caml-list

AGPL code for this site: git clone https://public-inbox.org/ public-inbox