Need help understanding Tuple

[John Chapman]

On Tuesday, 18 December 2012 at 11:06:12 UTC, d coder wrote:
> Greetings
>
> Somebody please help me understand why we need the Tuple 
> template in the
> following code. Does not __traits(getAttributes, foo.a) return 
> a tuple? So
> what is the Tuple template doing here? Converting a tuple to a 
> tuple?
>
> Also where to learn more about tuples in D. Info in TDPL is 
> sketchy.

The spec goes into tuples in some depth: 
http://dlang.org/tuple.html