use of at.ac.tuwien.kr.alpha.antlr.ASPCore2Parser in project Alpha by alpha-asp.
the class Main method parseVisit.
public static ParsedProgram parseVisit(ANTLRInputStream is) throws IOException {
/*
// In order to require less memory: use unbuffered streams and avoid constructing a full parse tree.
ASPCore2Lexer lexer = new ASPCore2Lexer(new UnbufferedCharStream(is));
lexer.setTokenFactory(new CommonTokenFactory(true));
final ASPCore2Parser parser = new ASPCore2Parser(new UnbufferedTokenStream<>(lexer));
parser.setBuildParseTree(false);
*/
CommonTokenStream tokens = new CommonTokenStream(new ASPCore2Lexer(is));
final ASPCore2Parser parser = new ASPCore2Parser(tokens);
// Try SLL parsing mode (faster but may terminate incorrectly).
parser.getInterpreter().setPredictionMode(PredictionMode.SLL);
parser.removeErrorListeners();
parser.setErrorHandler(new BailErrorStrategy());
final CustomErrorListener errorListener = new CustomErrorListener(is.getSourceName());
ASPCore2Parser.ProgramContext programContext;
try {
// Parse program
programContext = parser.program();
} catch (ParseCancellationException e) {
// retry with LL parser and DefaultErrorStrategy printing errors to console.
if (e.getCause() instanceof RecognitionException) {
tokens.reset();
parser.addErrorListener(errorListener);
parser.setErrorHandler(new DefaultErrorStrategy());
parser.getInterpreter().setPredictionMode(PredictionMode.LL);
// Re-run parse.
programContext = parser.program();
} else {
throw e;
}
}
// is attempted) and the user will only see the first error encountered.
if (errorListener.getRecognitionException() != null) {
throw errorListener.getRecognitionException();
}
// Construct internal program representation.
ParsedTreeVisitor visitor = new ParsedTreeVisitor();
return (ParsedProgram) visitor.visitProgram(programContext);
}
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