check if its a DOC end sequence
function() {
    // @fixme : check if out of text limits
    if (
      this._input.substring(
        this.offset - 1,
        this.offset - 1 + this.heredoc_label.length
      ) === this.heredoc_label
    ) {
      const ch = this._input[this.offset - 1 + this.heredoc_label.length];
      if (ch === "\n" || ch === "\r" || ch === ";") {
        return true;
      }
    }
    return false;
  }