Re: OOD in Ada?

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

O.K. I understand where you were going with it now. I'd agree that trying to
make everything in a parse tree as you describe it use the type system to
try to guarantee correctness is a bad idea. Attempting to do so is only
likely to lead to fighting with the compiler endlessly & for little
advantage. Better to have the parser logic insure that only a correct parse
tree gets built & use a more loose level of type checking on the access
types.

It still leaves a hole in that someone could derive from the base class and
succeed in getting something into the parse tree that is incorrect - but
doing so would require some rather deliberate moves. The answer can be "Then
just don't do that!" because it isn't likely to happen just by an accidental
coding error.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com


<tmoran@acm.org> wrote in message
news:fKIS8.801$X14.133162217@newssvr13.news.prodigy.com...
>    I presume the OP wants to have things along the line of
>
>      type Adding_Operator is tagged record ...
>        Op_Char : character;
>      end record;
>      type Simple_Expression is tagged record>        Left :
Access_Simple_Expression;
>        Add_Op : Access Adding_Operator;
>        Right  : Access_Term;
>      end record;

>
<snip>