Re: [Caml-list] Newbie comment on constructor syntax

[Gabriel Scherer <gabriel.scherer@gmail.com>]

If we gave a functional semantic to the unapplied constructor, then I
think that good taste would mandate for the application of this
function and the application of the constructor to be equivalent. This
means that by choosing a tuple-taking function, we commit to the
tuple-application syntax (that nobody likes), and that choosing a
currified function creates an unpleasant inconsistency in the
language.

I don't know whether we could ever manage to transition to a currified
syntax for constructors, but right now it is at least conceivable
because the application syntax is just a concrete syntax choice, it
does not affect typing. Turning unapplied constructor into a function
(tuplified or currified) makes it a typing property, observable at
specification boundaries: we cannot change it.

On Mon, Nov 9, 2015 at 6:33 PM, Alain Frisch <alain.frisch@lexifi.com> wrote:
> On 09/11/2015 11:35, Andreas Rossberg wrote:
>>
>> Yes please, I would appreciate such sugar.
>
>
> I've now submitted a cleaner implementation, working on both expressions and
> patterns:
>
> https://github.com/ocaml/ocaml/pull/284
>
>> Even more I would appreciate
>> generalising that to allowing constructors to be used as first-class
>> expressions (i.e., unapplied "C" -> "fun (x1,...,xN) -> C (x1,...,xN)"
>> when C is a constructor with arity > 0). I had to write some AST mapping
>> code recently that would have vastly benefited from that.
>
>
> This is not covered (and now, it could simply be "fun x -> C x" :-)).  I
> don't see anything clever to be done on patterns for "unapplied
> constructors", though.
>
>
> Alain
>
>
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