Hi,

I am trying to understand tuples.
Does anybody know why line 11 below fail?
Is it conceptually wrong or is it a compiler glitch?

Erik

 1	import std.stdio;
 2
 3
 4	template Tuple1(E...)
 5	{
 6		alias E Tuple1; // Works
 7	}
 8
 9	template Tuple2(E...)
10	{
11		alias E[0..length] Tuple2;  // Sematicly the same (?) but fails
12	}
13
14	int main (char[][] args)
15	{
16		writefln(Tuple1!(3, 7L, 6.8));
17		writefln(Tuple2!(3, 7L, 6.8));
18
19		return 0;
20	}


a.d(11): tuple E is used as a type
a.d(11): Error: can only slice tuple types, not void
a.d(17): template instance a.Tuple2!(3,7L,6.8) error instantiating

Erik Baklund wrote:
> Hi,
> 
> I am trying to understand tuples.
> Does anybody know why line 11 below fail?
> Is it conceptually wrong or is it a compiler glitch?
> 
> Erik
> 
>  1	import std.stdio;
>  2
>  3
>  4	template Tuple1(E...)  5	{  6		alias E Tuple1; // Works
>  7	}	
>  8
>  9	template Tuple2(E...) 10	{ 11		alias E[0..length] Tuple2;  // Sematicly the same (?) but fails
> 12	}	
> 13
> 14	int main (char[][] args)
> 15	{
> 16		writefln(Tuple1!(3, 7L, 6.8));   17		writefln(Tuple2!(3, 7L, 6.8));   18
> 19		return 0;
> 20	}
> 
> 
> a.d(11): tuple E is used as a type
> a.d(11): Error: can only slice tuple types, not void
> a.d(17): template instance a.Tuple2!(3,7L,6.8) error instantiating

I think your DMD is too old.  Works fine here with v1.014.  There were a number of problems like that in older versions of dmd.

--bb