[r6rs-discuss] [Formal] (r6rs base) must also export _ and ... at
aghuloum at cs.indiana.edu
Thu Jan 25 09:29:53 EST 2007
On Jan 25, 2007, at 7:46 AM, AndrevanTonder wrote:
> My assumption was that ... and _ are bound in (r6rs base).
I see it in neither draft of the report that any of these is bound.
> If they are
> bound, exporting them is necessary for writing most useful macros.
They are not. But even if they were, I don't see them "necessary" for
"most" useful macros.
> It did not even occur to me originally that an implementor might leave
> them unbound, thereby preventing users from being able to do various
> useful things to them.
As far as my understanding of the current draft goes, an implementor
does not have a luxury of adding extra stuff to the (r6rs base) library.
As a matter of fact, I would expect the following behavior:
(library OK (export) (import (prefix (r6rs base) r6rs:))
(library NOT (export) (import (prefix (r6rs base) r6rs:))
[r6rs:else 13])) => &syntax violation
> Example of useful things:
Both examples are useful, yes. But leaving ... and => undefined does
not prevent the user from writing them. The cond example, in
is a trivial exercise.
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