Re: [VOTE] Userspace operator overloading

On 28.03.2020 at 10:22, Arnold Daniels wrote: > This issues become even more apparent when sequencing operations like `$a + > $b + $c - $d`. Trying left, then trying right, will make it very difficult > to determine the outcome of such a statement. > > The arguments against type hinting for operator methods, assume the "try > left/right" method. Instead, type hinting should be applied to determine > which method should be used. If both or neither methods are applicable, an > error must be thrown. This "try left/right" approach is how operator overloading works for internal classes[1], and apparently, it works quite well, as long as it is not overused. > With class inheritance, you also don't want to rely on the order of the > operands. If you're the creator of a library, that's out of your hands. If > both the parent and child class overwrite the operation, and both accept > the operands, then the child class should always be used. If a subclass overrides the operation, it would have to conform to parameter type contravariance, so it would always be used, anyway. [1] <https://github.com/php/php-src/blob/php-7.4.4/Zend/zend_operators.h#L934-L937> -- Christoph M. Becker