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

[Andrei Alexandrescu]

On 9/25/12 4:14 PM, Jonathan M Davis wrote:
> On Wednesday, September 26, 2012 04:29:13 kenji hara wrote:
>> But, the two are often confused, by the word "tuple". It has
>> introduced badly confusion in many discussions.
>> To make matters worse, it had often invoked incorrect suggestion that
>> merging the two into one.
>>
>> My suggestion is very simple.
>> 1. Change all words "built-in tuple" in the documentation to "built-in
>> sequence". Then, in the D language world, we can have clarify name for
>> the built-in one.
>> 2. Introduce new templates, Seq, TypeSeq, and ExpSeq.
>>
>> template Seq(T...) { alias T Seq; } // identical with
>> std.typetuple.TypeTuple
>> template TypeSeq(T...) if (allSatisfy!(isType, T)) { alias T TypeSeq; }
>> template ExpSeq(T...) if (allSatisfy!(isExpression, T)) { alias T
>> ExpSeq; }
>>
>> If you really want to a sequence with heterogeneous elements, use
>> Seq template. Otherwise use TypeSeq or ExpSeq based on your purpose.
>
> In principle, renaming TypeTuple makes sense given it's bad name (though I
> really don't seem much point in separating expression tuples and type tuples),
> but it would break a _lot_ of code. And both Walter and Andrei are
> increasingly against making any breaking changes.
>
> - Jonathan M Davis

TypeTuple does a lot of harm. I'd be glad to rename it GenericTuple and 
leave TypeTuple as a slowly rotting alias.

Andrei