Working examples how to use Antlr in Java

[Stjepan Vukadin]

Hi!

Every example page that I have found on the web (google) is using deprecated API. Where can I find up to date example how to load generated classes?

Thanks and kind regards,

Stjepan

[alex;]

Hi, Stjepan.

What mean to load?

example parsing

import org.antlr.v4.runtime.//<editor-fold defaultstate="collapsed" desc="/*comment*/">
        ANTLRInputStream
//</editor-fold>
;
import org.antlr.v4.runtime.CommonTokenStream;
import org.antlr.v4.runtime.tree.ParseTreeWalker;
import org.antlr.v4.runtime.ParserRuleContext;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;


public class MyGrammarCL {

    /**
     * @param args the command line arguments
     * @throws java.io.FileNotFoundException
     */
    public static void main(String[] args) throws FileNotFoundException, IOException {
        InputStream inputStream = new FileInputStream("c:\\dev\\MyGrammar\\utils\\hbmk2\\hbmk2_full.txt");
        ANTLRInputStream input = new ANTLRInputStream(inputStream);
        MyGrammarLexer lexer = new MyGrammarLexer(input);
        CommonTokenStream tokens = new CommonTokenStream(lexer);
        MyGrammarParser parser = new MyGrammarParser(tokens);
        System.out.println(new Date());
// Specify our entry point
        MyGrammarParser.FileProgramContext MyGrammar_fileContext1 = parser.fileProgram();
        System.out.println(new Date());
        ParseTreeWalker walker = new ParseTreeWalker();              
        AntlrMyGrammaristener listener = new AntlrMyGrammaristener();
        walker.walk(listener, MyGrammar_fileContext1);

    }

    private static class AntlrMyGrammaristener extends MyGrammarParserBaseListener {

        public AntlrMyGrammaristener() {
        }
        @Override
    public void enterEveryRule(ParserRuleContext ctx)
        {
            System.out.println(ctx.getClass().getName());
//            if (ctx.getClass().getName() != "MyGrammarParser+FileProgramContext" && ctx.GetType().ToString() != "MyGrammarParser+StatementsContext")
//                System.out.println(ctx.GetText());
        }
    }
   
}

example View AST by TestRig

java -cp c:\dev\antlr4\grammars-v4-master\MyGrammar\build\classes;c:\dev\antlr4\tool\target\antlr4-4.7.1-complete.jar org.antlr.v4.gui.TestRig MyGrammar statements -tree -gui c:\dev\antlr4\grammars-v4-master\MyGrammar\test\test.prg
rem -trace -diagnostics

[Stjepan Vukadin]

You provided a perfect example. By load I meant exactly what you provided (using them in a context to e.g. print AST or something similar).