Re: Assertions in Ada

[Brian Rogoff <bpr@shellx.best.com>]

On Thu, 21 Aug 1997, Tucker Taft wrote:
> Note that during the 9X design we did consider adding more complete
> assertion/invariant constructs, but dropped them in the desire to
> reduce the overall scope of the revision.

This decision seems exactly right to me, though for a different reason. It 
isn't clear to me that there is enough consensus on formal (in the sense of
"mathematically formal") programming methodologies to consider choosing a 
set of constructs to put in the language proper. It makes more sense to 
let people experiment with tools/notations/methods like Anna, Larch, Z, B, 
and others. So IMO, Ada got this right, and Eiffel got it wrong, just like 
Eiffel got modules wrong.

This "Eiffel envy" strikes me as kind of silly, since I don't find Eiffel a 
particularly elegant language.

> My biggest complaint about Eiffel (and Java, for that matter), however, 
> is that they don't physically separate interface from implementation (except 
> via the notion of "deferred" classes).  

Agreed. Separate package spec and body is a nice feature.

-- Brian