Function parseExpression

01.GettingStarted/js/vue.js:2967–2988

* Parse an expression into re-written getter/setters. * * @param {String} exp * @param {Boolean} needSet * @return {Function}

(exp, needSet)

   */

  function parseExpression(exp, needSet) {
    exp = exp.trim();
    // try cache
    var hit = expressionCache.get(exp);
    if (hit) {
      if (needSet && !hit.set) {
        hit.set = compileSetter(hit.exp);
      }
      return hit;
    }
    var res = { exp: exp };
    res.get = isSimplePath(exp) && exp.indexOf('[') < 0
    // optimized super simple getter
    ? makeGetterFn('scope.' + exp)
    // dynamic getter
    : compileGetter(exp);
    if (needSet) {
      res.set = compileSetter(exp);
    }
    expressionCache.put(exp, res);
    return res;
  }

  /**
   * Check if an expression is a simple path.