static S input(S msg) {
  say(msg);
  ret input();
}

static S input() {
  bool e = consoleInputEnabled();
  if (!e) enableConsoleInput();
  S s = readLine();
  if (!e) disableConsoleInput();
  if (ai_enabled() && s != null) post("User", "said", quote(s));
  ret s;
}