Tuple and tie?

[NCrashed via Digitalmars-d-learn]

On Tuesday, 8 July 2014 at 17:42:00 UTC, Remo wrote:
>
> How to make something that work like std::tie in D2 ?
>
> Tuple!(float, float) sinCos(float n) {
>   return tuple(cast(float)sin(n), cast(float)cos(n)); //please 
> note cast(float)!
> }
>
> int main(string[] argv) {
>  float s,c;
>  tie!(s,c) = sinCos(3.0f);
> }

Try the following approach:
```
import std.typecons;
import std.typetuple;
import std.math;
import std.stdio;

auto tie(StoreElements...)(ref StoreElements stores)
{
	alias Elements = staticMap!(Unqual, StoreElements);
	
	template toPointer(T)
	{
		alias toPointer = T*;
	}
	
	struct Holder
	{
		alias StoreElementsPtrs = staticMap!(toPointer, StoreElements);
		StoreElementsPtrs storePtrs;
		
		this(ref StoreElements stores)
		{
			foreach(i, _; StoreElements)
			{
				storePtrs[i] = &stores[i];
			}
		}
		
		void opAssign(Tuple!Elements values)
		{
			foreach(i, _; Elements)
			{
				*storePtrs[i] = values[i];
			}
		}
	}
	
	return Holder(stores);
}

Tuple!(float, float) sinCos(float n)
{
	return tuple(cast(float)sin(n), cast(float)cos(n)); //please 
note cast(float)!
}

void main()
{
	float s,c;
	tie(s,c) = sinCos(3.0f);
	writeln(s, " ", c);
}
```