Re: how to import a package

["markww" <markww@gmail.com>]

Ok I just broke down and wrote the test function to take a specific
PERSON_REC type to add into a new node. The program compiles and runs
as expected, but I just lost my generics support by doing this, I
think:

    procedure Add_Record(GenericData : PERSON_REC) is
    Temp : gNode.Node_Ptr;
    begin

        Temp := new gNode.Node;
        Temp.Data := GenericData;
    end Add_Record;

So yes now it runs ok and I can print the contents of the linked list
and see that a person record was added into the Data member.

But now I can't use this Add_Record function to store some other type
of user defined data, it will only work with PERSON_RECs.

I'm sorry, I still don't understand how to just pass a generic through
as a parameter!

Thanks,
Mark



Georg Bauhaus wrote:
> On Sun, 2006-12-10 at 22:50 -0800, markww wrote:
> >  So I made a test function like:
> >
> >      procedure Add_Record(GenericData : gNode.T) is
> >      Temp : gNode.Node_Ptr;
> >      begin
> >          Temp := new gNode.Node;
> >          Temp.Data := GenericData;
> >      end Add_Record;
> >
> > now the compiler is saying that my generic type T is not visible to the
> > rest of the application.
>
> The type T is in the formal part of the package, not in the package
> proper. So either you are explicit about T (you have made an
> instance of the package using Some_Type for T, so you can use
> Some_Type instead of gNode.T there, too) or you make your generic
> package have a type Gen_T by using "subtype Gen_T is T" or similar.
>
>
> > Also, is this procedure definition correct? In C++ it's easy to do this
> > after defining a type it would be just:
> >
> >     bool Add_Record (T t);
> >     template<typename T>
> >     bool CLinkedList<T>::Add_Record(T t)
> >     {
> >         // ...
> >     }
> 
> But here, you have one specific T and one generic T.