| Re: An overloading question [message #174497 is a reply to message #174496] |
Wed, 15 June 2011 00:45   |
Jerry Stuckle
Messages: 2598
Registered: September 2010
Karma:
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Senior Member |
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On 6/14/2011 7:43 PM, sheldonlg wrote:
> On 6/14/2011 7:12 PM, Jerry Stuckle wrote:
>> On 6/14/2011 6:27 PM, sheldonlg wrote:
>>> On 6/14/2011 2:32 PM, Denis McMahon wrote:
>>>> On Tue, 14 Jun 2011 12:49:11 -0400, sheldonlg wrote:
>>>>
>>>> > I have a problem that I am wrestling with that should be so obvious
>>>> > and
>>>> > easy -- but it isn't. I have a base class that has a method that calls
>>>> > another method in the base class with $this->thatOtherMethod. I have
>>>> > another class that extends the base class and I want to have
>>>> > thatOtherMethod in the extended class override the one in the base
>>>> > class. The calling method in the base class is called using and
>>>> > instance of the extended class pointing to that method.
>>>> >
>>>> > Simply, here is an example:
>>>> >
>>>> > A.class.php
>>>> > --------------------------
>>>> > <?php
>>>> > abstract class A {
>>>> > public function b() {
>>>> > $this->a();
>>>> > }
>>>> > protected function a() {
>>>> > print 'In class A';
>>>> > }
>>>> > }
>>>> > ?>
>>>> >
>>>> > B.class.php
>>>> > ---------------------------
>>>> > <?php
>>>> > include_once 'A.class.php';
>>>> > class B extends A {
>>>> > public function a() {
>>>> > print 'In class B';
>>>> > }
>>>> > }
>>>> > ?>
>>>> >
>>>> > c.php
>>>> > ----------------------------
>>>> > <?php
>>>> > include 'B.class.php';
>>>> > $x = new B();
>>>> > $x->b();
>>>> > ?>
>>>> > ----------------------------
>>>> >
>>>> > I want it to print out "In class B", but it prints out "In class A".
>>>> >
>>>> > I have looked over Google quite a bit and found nothing that helped. I
>>>> > have tried making the methods public, protected, keep them both the
>>>> > same
>>>> > access, etc. and have had no luck. Suggestions?
>>>>
>
>> Unfortunately, PHP doesn't really implement OO constructs very well - in
>> fact they to a pretty piss poor job of it. One of the problems is with
>> virtual functions, as you found. A good OO language would work like you
>> want, but PHP doesn't - the constructor for A will, in this case, only
>> call a function in A. In C++, Smalltalk, Java and most other OO
>> languages, you could define y() as virtual and the constructor for A
>> would call the function y() in B.
>
> I could define the method in A as abstract (and the class). It would
> then require that it be implemented in B. However, I am not the only
> application using A, and so doing that would require all the other apps
> to also implement it in an extended class. That is a no-no and is one of
> the reasons for using B in the first place.
>
>>
>> But if you created a constructor in B properly, it should call B:y().
>
> I did create a constructor in B properly.
>
>> I'd suggest checking your code again - you might have made a mistake.
>>
>
> No mistakes that I could find.
>
Id you created it properly, then the constructor in B should be calling
b::y().
I still suggest you have a mistake in your code.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex(at)attglobal(dot)net
==================
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