Generate Java/Python parser for syntax error checking in the browser

[Abdullah Hilson]

Hello,

I am trying to use ANTLR's grammars from https://github.com/antlr/grammars-v4 to create a linter for an online editor.

I could generate a java parser and python3 parser for javascript target following documentation.

Now I try to use the parser in a javascript script, I don't get any rules in the parser created:

const antlr4 = require('../antlr4-js/index')

const JavaLexer = require('./JavaLexer')

const JavaParser = require('./JavaParser')

var input = `

public class Main {

   public static void main(String[] args) {

       System.out.println("Hello, World!");

   }

}

`;

var chars = new antlr4.InputStream(input);

var lexer = new JavaLexer.JavaLexer(chars);

var tokens = new antlr4.CommonTokenStream(lexer);

var parser = new JavaParser.JavaParser(tokens);

parser.buildParseTrees = true;

console.log(Object.keys(parser))

// parser.parseMyRule();

I get these properties on the parser object:

[ '_listeners',

  '_interp',

  '_stateNumber',

  '_input',

  '_errHandler',

  '_precedenceStack',

  '_ctx',

  'buildParseTrees',

  '_tracer',

  '_parseListeners',

  '_syntaxErrors',

  'ruleNames',

  'literalNames',

  'symbolicNames' ]

I don't get compilationUnit or anything that looks like a rule function here.

I pushed my antlr-js and my code on a fork of the grammar here :

https://github.com/abumalick/grammars-v4/blob/master/java/test.js

One can clone the repository and run `node java/test.js` to see what I get.

I am stuck for 2 days on this. Am I missing something ?

Thank you very much

[Abdullah Hilson]

Really I don't understand this, it should have generated rules for compilationUnit, packageDeclaration, etc... https://github.com/abumalick/grammars-v4/blob/master/java/JavaParser.g4#L34

I don't see anything in the parser object..

Did anyone generate a parser from public grammars to javascript target ?

I tried with 4 or 5 grammars and every time I get no rule generated.

(https://github.com/antlr/grammars-v4)

[Abdullah Hilson]

Okay I understood now thanks to eric vergnaud here: https://github.com/antlr/antlr4/issues/2286#issuecomment-388080617

we have to look for the names of the rules in the generated Parser, so here it works with `parser.compilationUnit()`