From: Michael Vanier <mvanier@cs.caltech.edu>
To: Adam Granicz <granicz.adam@vnet.hu>
Cc: "caml-list@inria.fr" <caml-list@inria.fr>
Subject: Re: [Caml-list] syntax question
Date: Thu, 29 May 2008 18:13:09 -0700 [thread overview]
Message-ID: <483F54A5.4020808@cs.caltech.edu> (raw)
In-Reply-To: <op.ubxyg1hbibhf7u@ephubudl0046.budapest.epam.com>
Adam,
I realize that this is how it works, but I don't understand why it should work this way. AFAIK
elsewhere in ocaml "int * int" always refers to a tuple. Similarly, if testme's Foo really took two
int arguments I would expect to be able to create Foos as "Foo 1 2" instead of "Foo (1, 2)" which
looks like Foo takes a single tuple argument, not two int arguments. I don't see why "int * int"
and "(int * int)" are different things.
Mike
Adam Granicz wrote:
> Hi Michael,
>
> In the type definition
>
>> # type testme = Foo of int * int;;
>
> the constructor Foo takes *two* int arguments (thus, you can not
> construct a testme value supplying only one argument), whereas in
>
>> # type testme2 = Foo2 of (int * int);;
>
> it takes *one* tuple argument.
>
> Regards,
> Adam.
>
> On Fri, 30 May 2008 00:23:40 +0200, Michael Vanier
> <mvanier@cs.caltech.edu> wrote:
>
>> Hi everyone,
>>
>> I got bitten by a simple syntax problem:
>>
>> # let a = (1, 2);;
>> val a : int * int = (1, 2)
>> # type testme = Foo of int * int;;
>> type testme = Foo of int * int
>> # Foo a;;
>> The constructor Foo expects 2 argument(s),
>> but is here applied to 1 argument(s)
>> # Foo (1, 2);;
>> - : testme = Foo (1, 2)
>> # type testme2 = Foo2 of (int * int);;
>> type testme2 = Foo2 of (int * int)
>> # Foo2 a;;
>> - : testme2 = Foo2 (1, 2)
>>
>> Why does the compiler treat int * int and (int * int) in type
>> definitions so differently? Is it to give clearer error messages in
>> the typical case?
>>
>> Mike
>>
>>
>>
>>
>> _______________________________________________
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>
>
> _______________________________________________
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next prev parent reply other threads:[~2008-05-30 1:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-29 22:23 Michael Vanier
2008-05-30 0:32 ` [Caml-list] " Adam Granicz
2008-05-30 1:13 ` Michael Vanier [this message]
2008-05-30 1:48 ` Adam Granicz
2008-05-30 1:54 ` Gordon Henriksen
2008-05-30 7:03 ` Christophe TROESTLER
2008-05-30 7:06 ` Luc Maranget
2008-05-30 12:17 ` Damien Doligez
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