Re: Ripple effect

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

Robert A Duff wrote:
> 
> I suppose there are many other ways; I'm not sure which one you're
> leaning toward.  ;-)  Surely not to increase Beaujolais-like effects!?

The world would be a different place if we all drank a bottle of 
Beaujolais a day.

I'm leaning toward not have "use". It seems to work pretty well in 
SPARK. It also tends to make you think up good names.

> I'm not sure.  The user can declare a module "open".  If you say
> "use X", you get visibility on X (remember this is not Ada's "use").  If
> X is open, you also get (direct) visibility on the contents of X.  The
> part I'm not sure about is whether to _also_ provide something like
> Ada's "use" clause, which allows clients of a non-open module to open
> it.  It could work for records, too, like Pascal's "with" statement --
> except that I would eliminate the nasty Beaujolais-like effects of
> Pascal.

Thanks for the explanation.

I never found Pascal's "with" to be very useful.

> I guess I'm confused as to what the issue is, then.  If B doesn't
> reference A, then it shouldn't import it -- and the compiler should
> give a (suppressable) error.  Suppressable because you might want unused
> imports temporarily during construction.  Also, there are some cases
> where unused imports are needed.

I would probably outlaw them completely, with a way to create exceptions 
when they're actually needed.

-- 
Jeff Carter
"Pray that there's intelligent life somewhere up in
space, 'cause there's bugger all down here on earth."
Monty Python's Meaning of Life
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