How would you do this in D?

[Jose Armando Garcia]

Hey guys,

I am trying to create a function that return true or executes
"something" the n-th time it is called from a specific call site. How
would you do that in D? In C we can do that with the help of
pre-processor macros. E.g.:

---
#include <assert.h>

#define EVERY(N, ACTION) { static int counter = 0; if(++counter > (N))
counter -= (N); if(counter == 1) (ACTION); }

int main()
{
   int i = 0;
   int j = 0;
   while(i < 10)
   {
      EVERY(10, ++j);
      EVERY(2, ++i);
   }
   assert(j == 2);
   assert(i == 10);
}
---

In D, I hacked the following implementation. I don't like this
implementation for a log of reason... Am I missing some D feature? Can
someone do better?

---
int[string] map;

bool every(string file = __FILE__, int line = __LINE__)(int time)
{
   // assume file ~ "+" ~ to!string(line) is unique
   // assumption could be removed by using a struct
   string key = file ~ "+" ~ to!string(line);

   map[key] += 1;
   if(map[key] > time) map[key] -= time;

   return map[key] == 1;
}

unittest
{
   auto i = 0;
   auto j = 0;
   while(i < 10)
   {
      if(every(10)) ++j;
      if(every(2)) ++i;
   }
   assert(j == 2);
   assert(i == 10);
}

void main() {}
---

Thanks!
-Jose