DIP19: Remove comma operator from D and provision better syntactic support for tuples

[foobar]

On Sunday, 23 September 2012 at 20:57:48 UTC, foobar wrote:
> On Sunday, 23 September 2012 at 20:39:38 UTC, Andrei 
> Alexandrescu wrote:
>> I discussed this with Walter, and we concluded that we could 
>> deprecate the comma operator if it helps tuples. So I started 
>> with this:
>>
>> http://www.prowiki.org/wiki4d/wiki.cgi?LanguageDevel/DIPs/DIP19
>>
>> Unfortunately, I started much cockier than I ended. The 
>> analysis in there fails to construct a case even half strong 
>> that deprecating the comma operator could significantly help 
>> tuples. Well it essentially concludes that tuples are mostly 
>> fine as they are, and attempts to embellish them syntactically 
>> are marred with unexpected problems. Nevertheless, I sure have 
>> missed aspects all over, so contributions are appreciated.
>>
>>
>> Thanks,
>>
>> Andrei
>
>

Yay! vote += infinity

Regarding specifics,
I'd argue that (int) should be a perfectly valid construct. I
don't see what's confusing about that. I also am opposed to the
idea to limit tuples to 2 or more elements. On the contrary, I
root for the clean semantics of having a proper unit type
represented as () instead of the horrible C semantics of the
'void' type. Just make void an alias to () for backwards
compatibility.
Also, why the need to special case the for loop? the increment
part can be a regular tuple since the for loop doesn't assign
the value of the expression.
for (int i, j; cond; i++, j++) {}

I'd suggest looking at functional implementations such as ML or 
Haskel for more inspiration.