Comment by dcrazy

I’m curious why the author chose to model this as an assertion stack. The developer must still remember to consume the assertion within the loop. Could the original example not be rewritten more simply as:

    const result: ast.Expression[] = [];
    p.expect("(");
    while (!p.eof() && !p.at(")")) {
     subexpr = expression(p);
     assert(p !== undefined); // << here
     result.push(subexpr);
     if (!p.at(")")) p.expect(",");
    }
    p.expect(")");
    return result;