[fpc-devel] Abstract functons with parameters on classes

Peter Vreman peter at freepascal.org
Thu Jul 27 20:16:52 CEST 2006

> On 7/27/06, Jonas Maebe <jonas.maebe at elis.ugent.be> wrote:
>> On 27 Jul 2006, at 17:49, ik wrote:
>> > The issue is that TA is an abstract class, while TA2 and anything else
>> > will inherit this class, but will implement different things/ways of
>> > things ... so the "fnc" function will need a different structure on
>> > each class.
>> What is the use of having an abstract fnc in the base class? I don't
>> understand what you want to do. For calling these differently
>> structured "overloads" you have to typecast your class to TA2 or so
>> anyway, unless you declare all these variants also as virtual
>> abstract methods in your base class (in which case your problem is
>> immediately solved, but I don't really see the use of that because
>> you can't have generic code when calling any of these methods anyway).
> My wish to to make sure that the classes have the same function names,
> that only it's parameters are different depending on the need ....

That is ofcourse not possible because if you call a (virtual) method of TA
then the doesn't know anything about TA2. That is how the object model
works. You know things of the parent classes. But a parent class doesn't
know anything about it's children.

More information about the fpc-devel mailing list