RE: [PHP] Re: Copying an Object

From: chris h > On Fri, Sep 24, 2010 at 8:35 AM, Peter Lind <peter.e.lind@gmail.com> wrote: > > On 24 September 2010 14:22, Bob McConnell <rvm@cbord.com> wrote: > > From: David Hutto > > > >> On Fri, Sep 24, 2010 at 4:09 AM, Gary <php-general@garydjones.name> wrote: > >>> Daniel Kolbo wrote: > >>> > >>>> Say you have two classes: human and male. Further, say male extends > >>>> human. Let's say you have a human object. Then later you want to make > >>>> that human object a male object. This seems to be a pretty reasonable > >>>> thing to request of our objects. > >>> > >>> I don't think any human can change gender without major surgery, but I > >>> don't know if you just chose your example badly or whether you really > >>> think objects should be able to mutate into other types of object > >>> without some kind of special treatment. > >> > >> But it would work in something like makehuman, where you start with a neuter > >> form and scale one way or the other for physical features. If I > >> remember correctly, > >> we're' all xx until you become xy(genetically speaking). > > > > This is one of the details that really bothers me about OOP. It makes > it impossible to implement some very reasonable scenarios. 80% of the time, > when a patron is added to a system, we don't know which gender they are. > More than 50% of the time, we will never know, since the client doesn't keep > track of it. But the rest of them will be assigned sometime after they were > added. i.e. the gender assignment comes from a secondary source that is not > available at the time the patron is entered. > > > If you can't handle that, it's not the fault of OOP but your lack of > programming skills in OOP I'd say (and I mean no disrespect there, I'm > just pretty sure your scenario can be handled very easily in OOP). > > And no, I have no urge to defend OOP in PHP, I just see this entire > thread as a complete non-starter: if the language doesn't let you do > something in a particular way, how about you stop, take a breather, > then ask if perhaps there's a better way in the language to do what > you want done? That would normally be a much more productive and > intelligent response than either a) pressing on in the face of failure > or b) complaining about your specific needs and how the language fails > to meet them. > > I think pages 17-19 of the GoF covers exactly this: > > "Object composition is an alternative to inheritance." ... "Any > [composed] object can be replaced at run-time by another as long > as it has the same type." > > I would look into "object composition" or just read the GoF. GoF? Bob McConnell