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;
}