Expression | Markers Loop

try{
    markers = thisComp.layer("control").marker;// слой  с маркерами
    var nk;
    if(markers.nearestKey(time).time > time && markers.nearestKey(time).index-1 != 0){
        nk = markers.key(markers.nearestKey(time).index-1).time;
    }else{
        nk = markers.key(markers.nearestKey(time).index).time;
    }
    val1 = effect("Point A")(1).value; //Point Control
    val2 = effect("Point B")(1).value; //Point Control
    dur = effect("loopDuration, frames")(1).value*thisComp.frameDuration; //Slider Control
    t = time-nk;
    x = t%dur;
    linear(x, 0, dur, val1, val2);
}catch(err){
    value;
}