Re: [VOTE] Userspace operator overloading

On 28.03.2020 at 22:21, Andrea Faulds wrote: > Christoph M. Becker wrote: >> (frankly, I would not have not supported __concat() at all).  Also, >> overloaded operators should be programmed defensively, i.e. they should >> not accept arbitrary arguments (how could that even work?), but only >> those they can handle.  If implementations adhere to these "rules", I >> don't see real issues. > > Consider a type implementing some kind of list. Perhaps someone would > want to overload the + operator to mean adding an item to the list. If > the list accepts any type of value as a valid item, then you have an > example of an unconditional overload. I had already considered this, and wrote immediately above the quote: > If, for example, the + operator is overloaded to add something to a > collection, the normal expectation that + is commutative is already > violated. Operator overloading should definitely not be used for > "anything", but only for those rare cases which resemble math > operations Thanks, Christoph