Le 25/11/14 21:13, Vladimir Batov a écrit :
On 11/24/2014 09:07 PM, Andrzej Krzemienski wrote:
Anyone else? Would you be affected if operator<(optional<T>, T) is poisoned? (but operator==(optional<T>, T) remains working)
Another *pragmatic* point (probably more relevant for the std::optional variant) is if op<(T, optional<T>) is prohibited now and then later it is decided that decision was wrong (even though I can't possibly see how as it does not take *any* functionality away), then adding it back will not cause any issues. On the contrary, it op<() is allowed to stay now and later it's decided that decision was wrong and op<() is better taken out, then it won't be possible to do... well, much harder anyway as it's be a breaking change.
Following your reasoning, I will suggest to remove the implicit construction from T to optional<T> and/or remove the operator<(optional<T>, optional<>). If we can not live without them, we could always try to do whatever is better. Best, Vicente