从Antlr3到Antlr4的转换

Question

我正在将antlr3语法转换为antlr4语法。我已经去掉了所有的语法谓词。我正在努力对此进行正确的转换

    relaxed_date_month_first
  : relaxed_day_of_week? relaxed_month COMMA? WHITE_SPACE relaxed_day_of_month (relaxed_year_prefix relaxed_year)?
      -> ^(EXPLICIT_DATE relaxed_day_of_month relaxed_month relaxed_day_of_week? relaxed_year?)

到antlr4语法。

每次antlr4工具遇到"->“字符时，它都会显示”外部输入“->”期望{TOKEN_REF，RULE_REF...ACTION}“。

我该如何解决这个问题？

Answer 1

ANTLR4没有树重写功能。因此，完全删除-> ...：

relaxed_date_month_first
 : relaxed_day_of_week? relaxed_month COMMA? WHITE_SPACE relaxed_day_of_month (relaxed_year_prefix relaxed_year)?
 ;