how to iterate over an AA by key-value pair (tuple)?

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On Friday, 14 February 2014 at 09:30:30 UTC, bearophile wrote:
> Timothee Cour:
>
>> auto byKeyValue(){...}
>
> It's probably better to call the method "byPair" that is 
> shorter.
>
>
>> If I/someone does it, will it be merged in?
>
> Some people want those pairs to be tuples. But D lacks built-in 
> tuples, so you need to use typecons ones. But to use the 
> typecons ones you need to import half Phobos. It seems there is 
> no good solution.
>
> Bye,
> bearophile

I thought that the type of variadic template arg packs was 
considered D's tuple? The only problem is returning them from 
functions, but if that's fixed, would they not effectively be 
built-in tuples?