[R6RS] syntax-case semantics

[dyb at cs.indiana.edu]

> What does "unwilling to consider" mean in this context?  That
> you will vote against it when we vote?  Or that you will not
> allow this issue to come up for a vote?

The former, of course.  I don't know how I'd prevent a vote even if I
wanted to.

> So far as I know, we are not considering anything that would
> require macro-generated transformers to be recorded in files
> at all, let alone compiled files.

True, but we shouldn't preclude it or make it difficult either, especially
since we've identified allowing separate compilation as a priority for the
library system.  In general, if we make the representation less abstract,
we're going to eliminate some implementation choices and generally make
extensions, like compiled files, more difficult.

Incidentally, I have not proposed to include a syntax-object?  predicate
or to require that syntax objects be distinct from other types.  So while
standardizing on SRFI 72's less abstract representation would limit
implementation options and may inhibit various extensions, standardizing
on the more abstract representation does not.  In particular, if we
standardize on the more abstract representation, an implementation can
still employ the SRFI 72 representation.

Kent