Re: Problem with generic linked list package

[AdaMagica <christ-usch.grein@t-online.de>]

There is a declaration of Element before the functions:

     type Element is private;
>
>    with function "<"(Left, Right : Element) return Boolean is <>; 
>    with function "="(Left, Right : Element) return Boolean is <>; 
>
> There is no "<" and "=" defined for Element_Type, normally. So the "<>" seems to do the trick but why?
>
> The box tells the compiler that it will get the info it needs later. But in this case there is no later, isn't it?

There is a later indeed! It's when and where you instantiate the generic.

The actual type for Element you use to instantiate must have functions < and =. If not, the instantiation is illegal. The box <> tells the compiler: "Look at the place of the instantiation for those functions. If they exist, take them; if they don't exist, don't accept the instantiation."