DIP54 : revamp of Phobos tuple types

[Dicebot]

On Monday, 30 December 2013 at 06:42:56 UTC, Andrei Alexandrescu 
wrote:
>> If it is you judgement, let it be so. I prefer to start 
>> working on
>> implementation whatever it is as opposed to endless 
>> discussion. What is
>> your opinion about defining general guideline to use packs 
>> over nested
>> templates for multi-list algorithms (another disagreement 
>> between me and
>> Jakob)?
>
> I think an argument advocating a bunch of changes that add 
> chaff to code that works very well would have a hard time 
> geting off the ground. Use the right tool for the job - that's 
> why we're providing two of them.

It is not related to any existing code as there are no multi-list 
templates in std.typetuple right now. What I am speaking about is 
defining new ones in two possible ways:

template Equals(T1...)
{
     template To(T2...)
     { ... }
}

vs

template Equals(alias T1, alias T2)
     if (isTemplateArgumentPack!T1 && isTemplateArgumentPack!T2)
{
}

I think default Phobos style should be the latter while Jakob 
seems to favor the former. Judgement of uninterested party is 
welcome.