static String rep(int n, char c) {
  ret repeat(c, n);
}

static String rep(char c, int n) {
  ret repeat(c, n);
}

static <A> L<A> rep(A a, int n) {
  ret repeat(a, n);
}

static <A> L<A> rep(int n, A a) {
  ret repeat(n, a);
}