Re: Ripple effect

["Jeffrey R. Carter" <spam.not.jrcarter@acm.not.spam.org>]

Robert A Duff wrote:
> 
> The "Nada" thing was a joke.  I would not call a language "Nada", and
> certainly not "Duff".  ;-)

Nada sounds like a great name for a language :) "What's so great about 
this language?" "Oh, Nada."

You did indicate that you would probably name it after someone.

> I think you mean there is no equivalent of "use type".

IIRC, there is no equivalent of "use" or "use type". Of course, I may 
have misunderstood.

> No, I think you misunderstand the "Ripple Effect".  As I understand it,
> the Ripple Effect means that adding/removing a with_clause can cause
> compilation units that do not depend DIRECTLY on the modified thing to
> become illegal.  For example, suppose C with's B and B with's A.  Can a
> with_clause on A affect the legality of C?  If so, there's a Ripple
> Effect.

I've just rechecked the answer in the FAQ at adapower.com, and I think 
we're both mistaken: 'In brief, the (undesirable) Ripple effect was 
related to whether the legality of a compilation unit could be affected 
by adding or removing an otherwise unneeded "with" clause on some 
compilation unit on which the unit depended, directly or indirectly.' 
(Tucker Taft)

So it's not a with on C, as I thought, and can be a with on B, which you 
exclude. It also refers only to unneeded withs. So, if B withs A 
unnecessarily, that could cause a Ripple effect.

> Anyway, to answer Jeff's question:  I think with_clauses should be
> transitive in the first place, so that the Ripple Effect is not an
> issue.

So you mean, in the example you give above, that because C withs B and B 
withs A, that C withs A? Is that how your language works?

-- 
Jeff Carter
"Now look, Col. Batguano, if that really is your name."
Dr. Strangelove
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