inheritance of this kind is useful if you have common descendants for
specific types of object
object mammal (
function eat (mixed $food)
function shit ()
function sleep()
)
object carnivore extends mammal (
function eat (meat $food)
)
object herbivore extends mammal (
function eat (veggies $food)
)
now you can call the descendant mammal->eat() from carnivore->eat()
and herbivore->eat() to process foods.
their mammal->vitality settings (lets say its a subproperties-array)
will be updated, with custom handling taking place in carnivore->eat()
and herbivore->eat() while mammal->eat() is likely to update those
vitality properties..
another use, is a modification of a certain component.
descend it from the parent object and override the functions.
you can do pre processing and post processing by overriding functions.
On Wed, Jun 23, 2010 at 5:58 AM, Camilo Sperberg <unreal4u@xxxxxxxxx> wrote:
> Hello everybody :)
>
> I'm really intrigued on something... In what real-world applications could
> an extension of a class be really useful?
>
> Let's say I have this code:
>
> class foo {
> function hello_world($a) {
> echo 'foo hello world';
> }
>
> function bye_world() {
> echo 'foo bye world';
> }
> }
>
> class bar extends foo {
> function hello_world($a,$b) {
> echo 'bar hello world';
> }
> }
>
> Point 1: Why not just overwrite the hello_world method in the foo class in
> the first place? Wouldn't that save code and possible incompatibility or
> consistency issues between the code you've already written and between the
> two classes ? (Assuming that you do some things based on the $a and $b
> values).
>
> Point 2: On the other hand, maybe I could apply different operations to both
> (e.g.: return 1 in foo and 2 in bar), without breaking the basic
> functionality already achieved in the foo class. (Maybe considering that I
> want to apply an update or patch to an already existing application,
> however, is this is the scenario, I should always fix the old code wherever
> I invoke the foo class which returns us to point 1).
>
> Point 3: Ok, maybe I don't want a specific class to be so huge and I
> separate it into "pieces" of classes. But then again, wouldn't it be simpler
> to just save some code and keeping only one file with the entire class?
>
> Is it just that or do I miss something else? I'm not saying it is useless,
> it sounds indeed fantastic to work with... but I just can't imagine in what
> real-world cases this would be useful.
>
> Greetings !
>
> --
> Mailed by:
> UnReAl4U - unreal4u
> ICQ #: 54472056
> www1: http://www.chw.net/
> www2: http://unreal4u.com/
>
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