Correct, but the very beginning of the original article proposes running JSON through JSMin to support comments. So in this context, a "compiler" is being proposed (or transpiler to more modern). My comment isn't clear.
I'm dense: what's a combinator?
edit: Forgot partial application. Not strictly required, but super handy.
Edit: It’s not that accurate. It’s just math used in a way to compose parsers using parsers.