template in struct

[dsmith]

How to make workable something like this:

struct S (T...) {
   T args;
   string arg_str;

   foreach(i; args) {
     arg_str ~ to!string(i);
   }
}

void some_function(S s) {   // here ... Error: struct S(T...) is 
used as a type
   s.args = [a, b, c];
   string args = s.arg_str;
}