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

Purely functional parser combinators & AST generation for generic inputs

const comp = (...xforms) => {
  const [a, b, c, d] = xforms;
  switch (xforms.length) {
    case 0:
      return (x) => x;
    case 1:
      return a;
    case 2:
      return (scope, ctx, user) => b(a(scope, ctx, user), ctx, user);
    case 3:
      return (scope, ctx, user) => c(b(a(scope, ctx, user), ctx, user), ctx, user);
    case 4:
      return (scope, ctx, user) => d(c(b(a(scope, ctx, user), ctx, user), ctx, user), ctx, user);
    default:
      return (scope, ctx, user) => xforms.reduce((scope2, x) => x(scope2, ctx, user), scope);
  }
};
export {
  comp
};