Should the comma operator be removed in D2?

[Ellery Newcomer]

Bill Baxter wrote:
> On Tue, Nov 17, 2009 at 3:01 PM, Ellery Newcomer
> <ellery-newcomer at utulsa.edu> wrote:
>> Bill Baxter wrote:
>>> On Tue, Nov 17, 2009 at 1:51 PM, KennyTM~ <kennytm at gmail.com> wrote:
>>>> On Nov 18, 09 05:40, Ellery Newcomer wrote:
>>>>> Bill Baxter wrote:
>>>>>> However, I think for the good of humanity we can accept that one
>>>>>> little bizarre example of legal C syntax not doing the same thing in
>>>>>> D.
>>>>> int[] i;
>>>>>
>>>>> auto a = (i)[0];
>>>>>
>>>>> what does this do?
>>>> (i) should not construct a tuple. Probably (i,).
>>> That's Python's solution and it seems to work out ok.
>>>
>>> --bb
>> How do we express tuple types? ...
>> These won't work:
>> ...
>> (int,int) [] lst; //want
> 
> Why won't that work?  You may be right, but that particular
> declaration doesn't seem ambiguous to me.
> 
> --bb

foo!( (i,i) ) ();

compiler doesn't know if 'i' is a type or a variable.
Like I said, the problem already exists for eg

foo!( i ) ();

and isn't semantically ambiguous (as far as I know..), so it is doable.

at statement level, it would require a lot of lookahead to distinguish eg

(i,i)[0] = blah;
(i,i)[0] blah;

Not my idea of good language design (one character deep in the
production - can you say fortran :) actually fortran is worse, it
discards whitespace as token separators)