code: function isStandAloneExpression(text) {
          var found = ASTWalker.findNodeAt(getAST(text), 0, text.length, function (nodeType, node) {
              if (nodeType === "Expression") {
                  return true;
              }
              return false;
          });
          return found && found.node;
      }
docs: Checks whether the text forms a stand alone expression without considering the context of text
  @param {!string} text
  @return {boolean}