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From: Fraser Wilson <newsfraser@blancolioni.org>
Newsgroups: comp.lang.ada
Subject: Re: OOD in Ada?
Date: 26 Jun 2002 11:01:09 +0200
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Date: 2002-06-26T08:59:34+00:00
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"David Crocker" <dcrocker@eschertech.com> writes:

> There is no way I want to put all the expression and statement classes in
> one package! The natural way to construct the project is to put each class
> in its own file (and hence package, if I am using Ada).

Put just the abstract base classes for Expressions and Statements in
the same package, and put derived classes in their own packages.  You
could use child packages for this.

My compiler is structured along these lines:

   package Trees;   --  abstract base class for tree node
   package Trees.Expressions;
   package Trees.Expressions.Operators;
   -- ...
   package Trees.Statements;
   package Trees.Statements.Ifs;
   -- enzofoort

You get the idea.  If it turned out that expressions and statements
were mutually dependent, I would have either put them both in the same
package, or have only the package bodies rely on each other (which you
can do by casting down at run time -- not really recommended, but
nevertheless useful).

Fraser.