Re: Ripple effect

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Tue, 05 Sep 2006 02:33:47 GMT, Jeffrey R. Carter wrote:

> OK. In the discussion, your language used "use" in context clauses as 
> equivalent to Ada's "with" (which sounds like a good idea), and you 
> didn't show any equivalent to Ada's "use". I thought I recalled you 
> saying that the language didn't have one, but I guess IDRC.
> 
> If you do have an equivalent to Ada's "use", maybe it should be called 
> "see".

You don't need it, if the language offers constructs to handle namespaces,
especially to compose them out of existing ones. Then you could merge
specifications of several packages into a new specification and re-use it
where needed. 

>> Yes.  Do you think it should be otherwise? [transitive context clauses]
> 
> It seems awkward. We're working on a project. I create package B, which 
> has "with A;" on it. I thought B would need it, but I was wrong, and 
> forgot to remove it. You're developing C and need to use B, so you have 
> "with B;" on C. Then you realize you need to use A and write some code 
> that references A. You forget to put "with A;" on C, but it compiles OK 
> because B references A. Then I clean up B and remove the reference to A 
> from it. Now C doesn't compile. That seems undesirable.

You complain that missing "with" could be a lie, but it so anyway. I think
that management of non-transitive "with" is an unnecessary burden. If you
have 20+ packages, then it becomes unrealistic to inspect all with-clauses
each time you change something.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de