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Ray Blaak wrote:
> What happens if you need to do multiple actions for a library, e.g.
>
> (import (only "stack" push! pop!)
> (add-prefix "stack" stack:)
> (rename "stack" (clear! empty!))
>
> This could have a well-defined meaning (e.g. one gathers all "stack"
> related clauses to process them in aggregation), but it seems
> unnecessary, complex, and confusing to keep respecifying "stack"
I'm pretty sure the example above doesn't do what you intended. Based on
the spec, it would:
1. Import only push! and pop! from "stack," then
2. Import all identifiers from "stack" with the stack: prefix, then
3. Import all identifiers from "stack" again, except for clear!, which
is renamed to empty!.
The net result would include push!, stack:push!, stack:clear!, empty!,
etc. -- almost certainly not what you meant. If I understand correctly,
that's not even legal, since it imports some identifiers more than once.
Instead of importing "stack" multiple times with different modifiers, I
think you're supposed to nest the modifiers, with "stack" at the
innermost point, i.e.:
(import (add-prefix (rename (only "stack" push! pop! clear!)
(clear! empty!)
stack:)))
This version will:
1. Start with all identifiers from "stack."
2. Narrow the list to only push!, pop!, and clear!.
3. Rename clear! to empty!.
4. Apply the stack: prefix to all three names.
It avoids repetition of the "stack" and more precisely states how to
perform the namespace modifications. I think the result is a bit
obscure, although I would expect few programs to actually combine all
three modifiers like this.
--
Bradd W. Szonye
http://www.szonye.com/bradd