> On Jul 1, 2015, at 2:25 PM, Anatol Belski <anatol....@belski.net> wrote: > >> Expanding on this idea, a separate RFC could propose a magic > __cast($value) >> static method that would be called for code like below: >> >> $obj = (ClassName) $scalarOrObject; // Invokes >> ClassName::__cast($scalarOrObject); >> >> This would allow UString to implement casting a string to a UString and > allow >> users to implement such behavior with their own classes. >> >> However, I would not implement such casting syntax for UString only. Being > able >> to write $ustring = (UString) $string; without the ability to do so for > other classes >> would be unusual and confusing in my opinion. If an RFC adding such > behavior >> was implemented, UString could be updated to support casting. >> >> Obviously a UString should be able to be cast to a scalar string using > (string) >> $ustring. If performance is a concern, UString::__toString() should cache > the >> result so multiple casts to the same object are quick.
> Hi, > > One way doing this is already there thanks > https://wiki.php.net/rfc/operator_overloading_gmp . Consider > > $n = gmp_init(42); var_dump($n, (int)$n); > > However the other way round - could be done on case by case basis, IMHO. > Where it could make sense for class vs scalar, casting class to class is a > quite unpredictable thing. > > While users could implement it, how is it handled with arbitrary objects? > How would it map properties, would those classes need to implement the same > interface, et cetera? We're not in C at this point, where we would just > force a block of memory to be interpreted as we want. > > Regards > > Anatol Hello, I was thinking that the __cast() static method would examine the parameter given, then use that value to build a new object and return it or return null (which would then result in the engine throwing an Error saying that $scalarOrValue could not be cast to ClassName). It was just a suggestion to see what others thought because someone suggested supporting casting syntax such as $ustring = (UString) $scalarString. I don’t really care for either method though (__cast() or enabling casting just for UString), as they don't offer any advantage over writing new UString($string) or UString::fromString($string). Aaron Piotrowski -- PHP Internals - PHP Runtime Development Mailing List To unsubscribe, visit: http://www.php.net/unsub.php
