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

问题描述

按照接受的答案处理 ANTLR4 中的错误 问题我遇到了以下错误.

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

CustomErrorListener.java:11: 找不到符号
符号:变量 REPORT_SYNTAX_ERRORS
位置:类 CustomErrorListener

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

我知道处理 ANTLR4 中错误的方法与 ANTLR3 不同，基于上述问题及其答案，我最终实现了以下错误侦听器.

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，我在 ANTLR 文档的任何地方都找不到关于此 REPORT_SYNTAX_ERRORS 字段的任何信息.关于这可能来自什么的任何线索?

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 相同的文件，您从中复制并粘贴了 DescriptiveErrorListener 类.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，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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