code: public static <T> Parser<T> constant(final T v) {
      return new Parser<T>() {
        @Override boolean apply(ParseContext ctxt) {
          ctxt.result = v;
          return true;
        }
        @Override public String toString() {
          return String.valueOf(v);
        }
      };
    }
docs: A {@link Parser} that always returns {@code v} regardless of input.