let tree = p.expectSingleResult(p.expectEOF(PROG.parse(lexer.parse(inputTxt))));
console.log("RESULT=" + tkTreeToSExp(tree));
let tree = p.expectSingleResult(p.expectEOF(PROG.parse(lexer.parse(inputTxt))));
console.log("RESULT=" + tkTreeToSExp(tree));