@thi.ng/parse/combinators/not.js

Purely functional parser combinators & AST generation for generic inputs

import { always } from "../prims/always.js";
const not = (parser, fail = always()) => (ctx) => {
  if (ctx.done) return false;
  ctx.start("");
  const res = parser(ctx);
  ctx.discard();
  return res ? false : fail(ctx);
};
export {
  not
};