tokenize.js

function tokenize(str) {
  str=str.replace(/\(/g,"( ");
  str=str.replace(/\)/g," )");
  arr = str.split(' ');

  return arr;
}

function InputToLObject(arr){
  var rtn;
      if(arr[0] == "("){
        rtn = InputToList(arr);
      }
      else if(isFinite(arr[0])){
       rtn = Number(arr.shift());
      }
      else{
       rtn = arr.shift();
      }
  return rtn;
}

function InputToList(arr){
  var list = [];
  arr.shift();
  while(arr[0] != ")"){
    list.push(InputToLObject(arr));
  }
  arr.shift();
  return list;
}