generics in Ada 83

["REH" <spamjunk@stny.rr.com>]

Is there a way to define a default for the with'd procedure in the
following example in Ada 83:

generic
    type X is private;
    with procedure Y(Z : in X);
package Foo;

I want to define a default for Y, but how can I without knowing X?

I have a generic package that has several with'd procedures, but
depending on what services the package provides are use, only a few of
the procedures may need to be defined.  I'd like to just default the
unused ones to stubs.

Thanks.