import { VisualBasic6Lexer, VisualBasic6Parser } from "vb6-antlr4";
import { ANTLRInputStream, CommonTokenStream } from "antlr4ts";

// Create the lexer and parser
let inputStream = new ANTLRInputStream(`
Private Sub Command1_Click ()
   Text1.Text = "Hello, world!"
End Sub
`);
let lexer = new VisualBasic6Lexer(inputStream);
let tokenStream = new CommonTokenStream(lexer);
let parser = new VisualBasic6Parser(tokenStream);

let tree = parser.startRule();

// ...
import { VisualBasic6Listener, SubStmtContext } from "vb6-antlr4";
import { ParseTreeWalker } from "antlr4ts/tree";

class EnterSubListener implements VisualBasic6Listener {
  enterSubStmt(context: SubStmtContext) {
    console.log(`Sub start line number ${context._start.line}`);
    // ...
  }

  // other enterX functions...
}

// Create the listener
const listener: VisualBasic6Listener = new EnterSubListener();
// Use the entry point for listeners
ParseTreeWalker.DEFAULT.walk(listener, tree);

// ...
import { VisualBasic6Visitor, SubStmtContext } from "vb6-antlr4";
import { AbstractParseTreeVisitor } from "antlr4ts/tree";

// Extend the AbstractParseTreeVisitor to get default visitor behaviour
class CountSubsVisitor
  extends AbstractParseTreeVisitor<number>
  implements VisualBasic6Visitor<number> {

  defaultResult() {
    return 0;
  }

  aggregateResult(aggregate: number, nextResult: number) {
    return aggregate + nextResult;
  }

  visitSubStmt(context: SubStmtContext): number {
    return 1 + super.visitChildren(context);
  }
}

// Create the visitor
const countSubsVisitor = new CountSubsVisitor();
// Use the visitor entry point
const count = countSubsVisitor.visit(tree);
console.log(`There are ${count} Subs`);