Variadic templates

[Knud Sørensen]

On Thu, 02 Nov 2006 02:02:35 -0800, Walter Bright wrote:

> Oskar Linde wrote:
>>> There's a lot of unexplored territory with the tuples, they should be
>>> able to do a lot more than the current rather limited ability.
>> I am really excited about the possibilities here. Will tuples become real
>> types or a meta-types?
> 
> My current thought is that they will never be types, i.e. you will not 
> be able to have a "pointer to tuple" or "array of tuples". Also, they 
> will always be statically fixed at compile time. A tuple will simply be 
> a shorthand notation for a sequence of types or expressions.
> 
>> From the examples you show, I'd presume there is an implicit tuple expansion
>> when calling
>> 
>> void foo(int a, int b) {}
>> 
>> as foo(t); where t is a tuple of (int,int) ?
> 
> That's right. Those two declarations are the same thing. A function 
> parameter list is a tuple.
> 
Will something like this be possible ??

tuple t=(7, 'a', 6.8);

 print at t; // for print(7, 'a', 6.8)

>> will it be possible to declare a function such as taking a specific tuple
>> argument
> 
> I'm not sure what you mean. A function's parameter types *are* a tuple.
> 
>> and use tuples as return values etc?
> 
> That's something I want to make work.

Then you could write something like this.

print at func1@func2 at t; // for print(func1(func2(7, 'a', 6.8)));