sbool ai_evalFunctionCallLHS(BasicLogicRule rule, IF1<S, O> getFunction) {
  if (rule.lhs instanceof FunctionCall) {
    FunctionCall fc = cast rule.lhs;
    O f = getFunction.get(fc.function);
    if (f == null) false;
    O result = callF(f, fc.args);
    if (isTrue(result)) true;
  }
  false;
}