static LS ai_spaceToSpace(S space1, S space2, Collection<S> inputs, O... _) {
  ret map(s -> ai_spaceToSpace(space1, space2, s, _), inputs);
}

sS ai_spaceToSpace(S space1, S space2, S input, O... _) {
  S userName = optPar userName(_, 'usery);
  S computerName = optPar computerName(_, 'computery);
  if (eq(space1, 'user) && eq(space2, 'objective))
    ret switcheroo_youToName(computerName, switcheroo_iToName(userName, input));
  if (eq(space1, 'objective) && eq(space2, 'computer))
      ret switcheroo_nameToYou(userName, switcheroo_nameToI(computerName, input));
    ret input;
}