Re: __toString(), __toArray()

Hello, On Tue, Jan 12, 2010 at 11:40 PM, Chris Stockton <chrisstocktonaz@gmail.com> wrote: > Hello, > > On Mon, Jan 11, 2010 at 8:32 PM, mm w <0xcafefeed@gmail.com> wrote: >> cast is not needed in PHP >> >> i 'd rather be more interesting in >> >> class Obj { >>     function __catch($data, $type) { >>            //$type [ static_method, method, get_property, set_property] >>            if (observed &&  $type == set_property && >> somevalueIsObserved) { >>                  $observer->notify("somevalue::valueWillChanged"); >>                  $this->somevalue = $data['somevalue']; >>                  $observer->notify("somevalue::valueDidChanged"); >>            } else { >>                  continue__call(); >>            } >>     } >> } > > What? ... > >>> Etienne Kneuss wrote: >>> This is where operator over-loading would be useful however perhaps only >>> explicit casts would make sense here. > > I beleive adding a __cast(string $type) would be a useful feature for > me, very often I have a toArray method defined. I agree with you that > due to unexpected edge cases with operator precedence and general type > juggling that __cast should only be called on explicit (cast). > > I.E.: > class Int { public function __cast($type) { return 'int' == $type ? 15 : 0; } } > $r = new Int; This is an exemple where __cast would be very wrong. At the very least, it should return a value that is an inhabitant of the requested type! Do you really want (bool)new Int() to be Int 0? as a result, you have three solutions: 1) have the engine issue an error in case the return value is not compatible 2) provide a return value for every possible types requested 3) throw an exception in case the cast is not handled In the end, it looks way more complicated/magic than _simply_ defining a toArray method that is used whenever you need an object to be an array. You need an explicit cast anyway, so it's (array)$obj vs $obj->toArray(). > > var_dump($r + 1); // 2 > var_dump((int) $r + 1); // 16 > var_dump((bool) $r + 1); // 1 > > -- > PHP Internals - PHP Runtime Development Mailing List > To unsubscribe, visit: http://www.php.net/unsub.php > > -- Etienne Kneuss http://www.colder.ch