[r6rs-discuss] Importing set! into a single phase

[AndrevanTonder]

According to section 9.1, the base library exports set! for levels 0 and 1.
As a result, there does not seem to be any way that a client library can
import set! into a single level.

One way of addressing this would be for the base library to remain as
specified, but to provide an additional library separately that exports only
set! at level 0.

Andre