fcn bsearch(list,value){	// list is sorted
   fcn(list,value, low,high){
      if (high < low) return(Void);	// not found
      mid:=(low + high) / 2;
      if (list[mid] > value) return(self.fcn(list,value, low,   mid-1));
      if (list[mid] < value) return(self.fcn(list,value, mid+1, high));
      return(mid);			// found
   }(list,value,0,list.len()-1);
}