Re: What is derived?

[Martin Krischik <krischik@users.sourceforge.net>]

Rick Santa-Cruz wrote:

> Hi,
> 
> thanks for your answer!
> 
>>> At least I think, that private-methods are inherited, or am I wrong?
>>
>> If by "private-methods" you mean "subprograms declared in the private
>> part of the package spec", then yes and no. They will be derived if
>> they are visible at the point of derivation.
> What do you mean with visible at the point of deriviation? For example if
> a procedure is declared after the a type is derived, then is this
> procedure not visible? Are there more special cases?

Remember that private work on child packages and not on child classes.

So a child class which is inside a child packages can see procedures
declared inside private.

A child class declared in an unrelated package can not see the private part
and therefore cannot inherit private procedures.

If you are a C++ convert then I suggest to declare all child classes in
child packages -  that make transition easier for you

With Regards

Martin.

PS: The following creates a class where the outsild world does not know it
is OO. Favourite example is Unbounded_String. Since Unbounded_String may
not leak memory and almost no Ada compiler implements garbage collection it
needs some form of destructor. Therefore Unbounded_String is internally a
class.

package Hidden_Tag

  type Object is private;

private

  type Object is tagged private;

end Hidden_Tag;

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