Re: how to import a package

["Björn Persson" <spam-away@nowhere.nil>]

markww wrote:

> Yes I'm still confused - sorry - I'm coming from C++ / java and the ada
> syntax / scoping is a bit strange to me. So I thought a package is
> equivalent to a structure/class.

No, a struct in C would be a record in Ada. A class in C++ corresponds to a
tagged record type in Ada. C++ doesn't have anything quite like a package;
I'd say the closest you get is a namespace. In Java, the classes serve as
both data types and packages. Not so in Ada. An Ada package isn't a data
type any more than a C++ namespace is.

What you have is a generic package. Generics in Ada fill the same role as
templates in C++, but they're not quite the same thing. When you
instantiate a C++ template you get a class ? a data type. When you
instantiate a generic package in Ada you get a package, which can in turn
contain data types, subprograms and other things. (Ada also has generic
subprograms, but no generic data types.)

> So the line:
> 
>     Start : Person_List.Node_Ptr;
> 
> doesn't make sense to me since it looks like 'Start' is being defined
> as pointing to Person_List.Node_Ptr, when I thought the right side of
> the colon must be a data type.

Right. Node_Ptr is a data type, and its declaration is to be found in the
package Person_List. Start is an object (a variable) of this type.

-- 
Bj�rn Persson                              PGP key A88682FD
                   omb jor ers @sv ge.
                   r o.b n.p son eri nu