Javascript grammar in antlr4 and python

Question

I have used the following link for JavaScript grammar .

https://github.com/antlr/grammars-v4/tree/master/javascript/javascript/Python

i have used antlr4.8 and ntlr4-python3-runtime==4.8. when i use the following code it gives following error .
error:

PS N:\antlr4\sample\py4.8> python main.py test.js
Running
Test started for: test.js
Created parsers
Traceback (most recent call last):
  File "main.py", line 25, in <module>
    main(sys.argv)
  File "main.py", line 20, in main
    tree = parser.program()
  File "N:\antlr4\sample\py4.8\JavaScriptParser.py", line 880, in program
    self.enterRule(localctx, 0, self.RULE_program)
  File "C:\Users\root\AppData\Local\Programs\Python\Python38\lib\site-packages\antlr4\Parser.py", line 366, in enterRule
    self._ctx.start = self._input.LT(1)
.
.
.
  File "N:\antlr4\sample\py4.8\JavaScriptLexer.py", line 919, in sempred
    return pred(localctx, predIndex)
  File "N:\antlr4\sample\py4.8\JavaScriptLexer.py", line 925, in HashBangLine_sempred
    return  this.IsStartOfFile()
NameError: name 'this' is not defined

code:

import sys
from antlr4 import *
import JavaScriptLexer
import JavaScriptParser

JSL = JavaScriptLexer.JavaScriptLexer
JSP = JavaScriptParser.JavaScriptParser

class WriteTreeListener(ParseTreeListener):
    def visitTerminal(self, node:TerminalNode):
        print ("Visit Terminal: " + str(node) + " - " + repr(node))

def main(argv):
    input_stream = FileStream(argv[1])
    print("Test started for: " + argv[1])
    lexer = JSL(input_stream)
    stream = CommonTokenStream(lexer)
    parser = JSP(stream)
    print("Created parsers")
    tree = parser.program()
    ParseTreeWalker.DEFAULT.walk(WriteTreeListener(), tree)

if __name__ == '__main__':
    print("Running")
    main(sys.argv)

print("Hello")

What have I done wrong ?

Answer 1

Replace this with self (ref here). Example:

Change return this.IsStartOfFile() to return self.IsStartOfFile().