@thi.ng/parse/combinators/xform.js

Purely functional parser combinators & AST generation for generic inputs

const xform = (parser, xf, user) => (ctx) => {
  if (parser(ctx)) {
    const children = ctx.scope.children;
    const scope = children[children.length - 1];
    if (xf(scope, ctx, user)) {
      if (scope.children && !scope.children.length) {
        scope.children = null;
      }
    } else {
      children.pop();
    }
    return true;
  }
  return false;
};
export {
  xform
};