从 Antlr3 转换为 Antlr4

本文介绍了从 Antlr3 转换为 Antlr4的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我正在将 antlr3 语法转换为 antlr4 语法.我已经去掉了所有的句法谓词.我正在努力对此进行正确转换

I am in the process of converting an antlr3 to antlr4 grammar. I have stripped out all the syntactic predicates. I am struggling to make a correct conversion of this

    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，它都会说外部输入 '->' 需要 {TOKEN_REF, RULE_REF...ACTION}".

to antlr4 grammar.

Everytime the antlr4 tool runs into "->" character it says "extraneous input '->' expecting {TOKEN_REF, RULE_REF...ACTION}".

我该如何解决这个问题?

How do I fix this?

推荐答案

ANTLR4 没有树重写.因此，删除 ->... 完全:

ANTLR4 has no tree-rewriting. So, remove -> ... entirely:

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

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