Can't use variadic arguments to functions that use templates

[JS]

On Tuesday, 23 July 2013 at 19:14:26 UTC, H. S. Teoh wrote:
> On Tue, Jul 23, 2013 at 08:54:12PM +0200, Jesse Phillips wrote:
>> On Tuesday, 23 July 2013 at 16:22:38 UTC, JS wrote:
>> >On Tuesday, 23 July 2013 at 16:15:03 UTC, Jesse Phillips 
>> >wrote:
>> >>On Tuesday, 23 July 2013 at 14:03:01 UTC, JS wrote:
>> >>>I don't think you understand(or I've already got 
>> >>>confused)...
>> >>>
>> >>>I'm trying to use B has a mixin(I don't think I made this
>> >>>clear). I can't use it as a normal function. e.g., I can't
>> >>>seem to do mixin(B(t)). If I could, this would definitely
>> >>>solve my problem.
>> >>...[Code]...
>> >What good does that do?
>> >
>> >What if I want to use a run-time variable in the mix?
>> 
>> Ah, I understand now you're interested in:
>> 
>> string concat(alias Data...)() { ... }
>> 
>> This does not exist, but maybe it should... I don't know of a
>> workaround to get this behavior.
>
> Is this by any chance related to that other thread about 
> compile-time
> optimized join()? 'cos if it is, I've already solved the 
> problem via
> templates:
>
> 	import std.stdio;
> 	
> 	template tuple(args...) {
> 		alias tuple = args;
> 	}
> 	
> 	/**
> 	 * Given a tuple of strings, returns a tuple in which all 
> adjacent compile-time
> 	 * readable strings are concatenated.
> 	 */
> 	template tupleReduce(args...)
> 	{
> 		static if (args.length > 1)
> 		{
> 			static if (is(typeof(args[0])==string) &&
> 				__traits(compiles, { enum x = args[0]; }))
> 			{
> 				static if (is(typeof(args[1])==string) &&
> 					__traits(compiles, { enum x = args[1]; }))
> 				{
> 					alias tupleReduce = tupleReduce!(args[0] ~
> 								args[1], args[2..$]);
> 				}
> 				else
> 				{
> 					alias tupleReduce = tuple!(args[0], args[1],
> 								tupleReduce!(args[2..$]));
> 				}
> 			}
> 			else
> 			{
> 				alias tupleReduce = tuple!(args[0],
> 							tupleReduce!(args[1..$]));
> 			}
> 		}
> 		else
> 		{
> 			alias tupleReduce = args;
> 		}
> 	}
> 	
> 	void main() {
> 		string x = "runtime1";
> 		string y = "runtime2";
> 		auto arr = [ tupleReduce!("a", "b", x, "c", "d", y, "e", "f", 
> "g", x) ];
> 		writeln(arr);
> 	}
>
> The output is:
>
> 	["ab", "runtime1", "cd", "runtime2", "efg", "runtime1"]
>
> All compile-time readable strings in the list have been 
> concatenated at
> compile-time.
>
>
> T

Thanks, I'll check it out when I get a chance and report back. It
looks like it solves the problem.