Re: Child packages

[mbk@inls1.ucsd.edu (Matt Kennel)]

Robert I. Eachus (eachus@spectre.mitre.org) wrote:
: In article <3816h5$n3g@schonberg.cs.nyu.edu> dewar@cs.nyu.edu (Robert Dewar) writes:

:  > One thing that should be emphasized about child packages (since some of
:  > the posts of this thread have not been clear on this point) is that
:  > child packages in no way change their parents. If you have a parent A,
:  > and a child A.B, then if A.B does horrible things to the abstractions
:  > in A, it still does not affect anyone who with's only package A. It is
:  > only if package A.B is with'ed that the effects of the child are
:  > noticable.

:      Very misleading.  If a PROGRAM doesn't include any withs of a
: child, the child is not part of that program and can't harm it.  But a
: child unit can--even during elaboration--change hidden state in the
: parent's private part. 

Question:  do you mean objects declared to be type of the parent
may be harmed due to the fact that there are subclasses of
this parent?  This sounds dumb.  This isn't true, is it?

Of course, if you create a child class which takes some implementation
from a parent sure you might screw up the implementation taken from
the parent, but this should only affect you if you use
objects of the child class, right?

: 					Robert I. Eachus

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-Matt Kennel  		mbk@inls1.ucsd.edu
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