use interrupts on C-level

I'm afraid there isn't anything at the moment - it'd just be a matter of having a static variable, of multiple functions if you wanted to allow multiple instantiation...

Also, there's no need for jsvNewNativeFunction... you can just do:

void gotInterrupt(int n, ... ){ jsWarn("got it %j",n); }
void jswrap_Gesture_scan(JsVar *parent){
  JsGesture gest;
  if(!getFromVar(&gest,parent)) return;
  IOEventFlags exti = EV_NONE;
  if (!jsiIsWatchingPin(gest.data.echo))
    exti = jshPinWatch(gest.data.echo, true);
    // disable event callbacks by default
  if (exti) {
    jshSetEventCallback(exti, (JshEventCallbackCallback)gotInterrupt);
  }
}

So I guess a multi-function might look like:

JsVar *parents[4]  {0,0,0,0};
void gotInterrupt1(int n, ... ){ /* parents[0] */ }
void gotInterrupt2(int n, ... ){ /* parents[1] */ }
void gotInterrupt3(int n, ... ){ /* parents[2] */ }
void gotInterrupt4(int n, ... ){ /* parents[3] */ }
const JshEventCallbackCallback gotInterrupts[4] = { gotInterrupt1, gotInterrupt2, gotInterrupt3, gotInterrupt4 };

void jswrap_Gesture_scan(JsVar *parent){
  JsGesture gest;
  if(!getFromVar(&gest,parent)) return;
  IOEventFlags exti = EV_NONE;
  if (!jsiIsWatchingPin(gest.data.echo))
    exti = jshPinWatch(gest.data.echo, true);
  if (exti) {
    int n = 0;
    while (parents[n]) n++;
    if (n>3) {
     jsExceptionHere(JSET_ERROR, "Too many watches!");
     return;
    }
    jsvUnLock(parents[n]);
    parents[n] = jsvLockAgain(parent);
    jshSetEventCallback(exti, (JshEventCallbackCallback)gotInterrupts[n]);
  }
}