docs: function handler(instance, context, func, index, callback) {
  	return function() {
  		var old = instance.results[index];
  		instance.results[index] = tryExpr(func, context);
  		if (old === instance.results[index])
  			return;
  		if (instance.dependenciesCount === 1 || !Interpolable.allowDelayedUpdate)
  			callback(instance.output(context), 'set');
  		else if (!instance.willFire)
  			instance.willFire = context.delay(function() { // call on nextTick to manage other dependencies update without multiple rerender
  				if (instance.willFire) {
  					instance.willFire = null;
  					callback(instance.output(context), 'set');
  				}
  			}, 0);
  	};
  }