zformat3.cpp

This sketch performs the same functions as zformat2::cpp, but uses recursive printf/scanf calls inside the custom handlers, to reduce the number of lines of code we have to write, and just to show we can. (Though convenient, note that this version consumes more stack space that the previous.)

// Demonstrate recursive custom formatting and scanning using the '%Z'
// and '%z' codes.

struct TwoD {                   // Simple 2D coords based on shorts
  s16 x;                        // +-32K x range
  s16 y;                        // +-32K y range
};

void TwoDZPrinter(u8 face, void * arg, bool alt, int width, bool zerofill) {
  API_ASSERT_NONNULL(arg);      // Make sure we got an arg
  TwoD t = * (TwoD*) arg;       // Cast to the struct we require
  facePrintf(face,"(%d,%d)",t.x,t.y);  // Format our custom element, recursively
}

bool TwoDZScanner(u8 * packet, void * arg, bool alt, int width) {
  int x, y;
  if (packetScanf(packet,"(%d,%d)", &x, &y) != 5) // Recursive scanner call
    return false;
  if (arg) {                    // If they gave us a pointer
    TwoD * tp = (TwoD*) arg;    // Use it
    tp->x = x;
    tp->y = y;
  }
  return true;                  // Success!
}

void negateCoord(u8 * packet) {
  TwoD c;                       

  if (packetScanf(packet,"%Zn%z\n", TwoDZScanner, &c) != 3) {
    logNormal("Failed at %d\n",packetCursor(packet)); // Say where the parse died..
    return;
  }
  c.x = -c.x;                   // Negate the coord 
  c.y = -c.y;                   // they gave us

  facePrintf(packetSource(packet),"n%Z%z\n", TwoDZPrinter, &c); // Print result
}

void setup() {
  Body.reflex('n',negateCoord);
}

void loop() {
  /* nothing to do */
}