  peekAhead: function(i, e1, e2, e3, e4) {
    if (this.tokens.length > i) {
      var token = this.tokens[i];
      var t = token.text;
      if (t === e1 || t === e2 || t === e3 || t === e4 ||
          (!e1 && !e2 && !e3 && !e4)) {
        return token;
      }
    }
    return false;
  },
The software constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.