处理ANTLR中的错误4 [英] Handling errors in ANTLR 4

问题描述

在遵循接受的答案说明之后/ 2279200>处理ANTLR4中的错误问题我遇到以下错误。

After following the accepted answer's instructions of Handling errors in ANTLR4 question I stuck up with the following error.

CustomErrorListener.java:11：不能找到符号

符号：变量REPORT_SYNTAX_ERRORS

位置：class CustomErrorListener

CustomErrorListener.java:11: cannot find symbol
symbol : variable REPORT_SYNTAX_ERRORS
location: class CustomErrorListener

我明白处理ANTLR4错误的方法与ANTLR3不同，根据上述问题及其答案，我最终实施了以下错误侦听器。

I understood that ways to handle errors in ANTLR4 were different from ANTLR3, and based on the aforementioned question and its answers I ended up implementing the following error listener.

public class DescriptiveErrorListener extends BaseErrorListener {
    public static DescriptiveErrorListener INSTANCE = new DescriptiveErrorListener();

    @Override
    public void syntaxError(Recognizer<?, ?> recognizer, Object offendingSymbol,
                        int line, int charPositionInLine,
                        String msg, RecognitionException e)
    {
        if (!REPORT_SYNTAX_ERRORS) {
            return;
        }

        String sourceName = recognizer.getInputStream().getSourceName();
        if (!sourceName.isEmpty()) {
            sourceName = String.format("%s:%d:%d: ", sourceName, line, charPositionInLine);
        }

        System.err.println(sourceName+"line "+line+":"+charPositionInLine+" "+msg);
    }
}

不幸的是，我找不到任何关于这个 REPORT_SYNTAX_ERRORS 字段在ANTLR文档的任何地方。任何关于这可能来自哪里的线索？

Unfortunately I could not find anything about this REPORT_SYNTAX_ERRORS field anywhere in the ANTLR documentation. Any clue on what this could come from?

推荐答案

它在 class from。这是声明：

It's declared in the same file you copied and pasted the DescriptiveErrorListener class from. Here is the declaration:

private static final boolean REPORT_SYNTAX_ERRORS = true;

当值为 false 时， code> syntaxError 方法返回而不显示错误。

When the value is false, the syntaxError method returns without displaying errors.

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