oop

2.23: adda/oop/child pkg's similarity to subclasses:
. child pkg's are like subclasses
so how does ada handle choice of visible to public,
subclasses, self-only?

adda/oop/freedom with security:
. encapsulation means not having the freedom to
poke into privates .
. one way to have freedom too,
is using the unix idea of root user:
encapsulation can be broken in root.user mode .