Function.setUdas

import std.typecons : tuple;
@(666) int answer();

mixin(
  refract!(answer, "answer")
  .setName("answerIs42")
  .setUdas(["@(42)"])
  .mixture);
static assert(__traits(getAttributes, answerIs42).length == 1);
static assert(__traits(getAttributes, answerIs42)[0] == 42);