How to override error reporting in c++ target of antlr4? - antlr4

Question

To report errors in a different way in antlr4-java target, we do the following:
(1) define a new listener:
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)
{
String printMsg = String.format("ERR: %s:%d:%d: %s",
recognizer.getInputStream().getSourceName(), line,
charPositionInLine+1, msg);
System.err.println(printMsg);
}
}
(2) override the reporter for lexer and parser:
lexer.removeErrorListeners();
lexer.addErrorListener(DescriptiveErrorListener.INSTANCE);
..
parser.removeErrorListeners();
parser.addErrorListener(DescriptiveErrorListener.INSTANCE);
What would be the corresponding code in c++ target?

Answer 1

In C++ it's almost identical (aside from the language specific aspects). Code I use:
struct MySQLParserContextImpl : public MySQLParserContext {
ANTLRInputStream input;
MySQLLexer lexer;
CommonTokenStream tokens;
MySQLParser parser;
LexerErrorListener lexerErrorListener;
ParserErrorListener parserErrorListener;
...
MySQLParserContextImpl(...)
: lexer(&input), tokens(&lexer), parser(&tokens), lexerErrorListener(this), parserErrorListener(this),... {
...
lexer.removeErrorListeners();
lexer.addErrorListener(&lexerErrorListener);
parser.removeParseListeners();
parser.removeErrorListeners();
parser.addErrorListener(&parserErrorListener);
}
...
}
and the listeners:
class LexerErrorListener : public BaseErrorListener {
public:
MySQLParserContextImpl *owner;
LexerErrorListener(MySQLParserContextImpl *aOwner) : owner(aOwner) {}
virtual void syntaxError(Recognizer *recognizer, Token *offendingSymbol, size_t line, size_t charPositionInLine,
const std::string &msg, std::exception_ptr e) override;
};
class ParserErrorListener : public BaseErrorListener {
public:
MySQLParserContextImpl *owner;
ParserErrorListener(MySQLParserContextImpl *aOwner) : owner(aOwner) {}
virtual void syntaxError(Recognizer *recognizer, Token *offendingSymbol, size_t line, size_t charPositionInLine,
const std::string &msg, std::exception_ptr e) override;
};