static long dm_evalOnOtherMachineWithReturnValue_timeout = 30000;

sS dm_evalOnOtherMachineWithReturnValue(fS computerID, S code) {
  fS id = aGlobalID();
  final new Var<S> var;
  temp vmBus_onMessage('gotFromChat, voidfunc(S msg) {
    if (var.has()) ret;
    new Matches m;
    if (!startsWith(msg, "done " + id + ": ", m)) ret;
    if (neq(getAuthorOfSignedText(msg), computerID)) ret;
    var.set(firstLine(m.rest()));
  });
  dm_osChat_postSigned(computerID + " eval " + id + ": " + code);
  ret waitForVarToBeNotNullWithTimeout(var, dm_evalOnOtherMachineWithReturnValue_timeout);
}