Antlr
ANTLR is a parser generator tool.
BITPlan has been using ANTLR in projects for a few years now and Wolfgang Fahl has been active in improving ANTLR see e.g. #Motivation
Library with helpers for ANTLR Language development com.bitplan.antlr
To simplify Parser development with ANTLR BITPlan has created a library with some helper code for ANTLR Language Development and published it as Open Source at:
Base Class Language Parser
The abstract base class LanguageParser has some help code that makes language development and debugging easier.
Example
/**
* example parser
* @author wf
*
*/
public class ExpLanguageParser extends LanguageParser {
private ExpParser parser;
ExpLexer lexer;
public ExpParser getParser() {
return parser;
}
@Override
protected ParseTree getRootContext(Parser parser) {
if (!(parser instanceof ExpParser)) {
throw new RuntimeException("wrong parser type for getRootContext, expected Rule but got "+parser.getClass().getName());
} else {
ExpParser expParser=(ExpParser) parser;
return expParser.eval();
}
}
@Override
protected ParseTree parse(ANTLRInputStream in, String inputText)
throws Exception {
lexer = new ExpLexer(in);
parser=new ExpParser(getTokens(lexer));
ParseTree result=super.parse(lexer,getParser());
return result;
}
@Override
public void showParseTree() {
super.showParseTree(getParser());
}
}