Re: Re: Copying an Object

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On Fri, Sep 24, 2010 at 8:35 AM, Peter Lind <peter.e.lind@xxxxxxxxx> wrote:

> On 24 September 2010 14:22, Bob McConnell <rvm@xxxxxxxxx> wrote:
> > From: David Hutto
> >
> >> On Fri, Sep 24, 2010 at 4:09 AM, Gary <php-general@xxxxxxxxxxxxxxx>
> 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.
>
> Regards
> Peter
>
> --
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>
>


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.

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