I don't like using set!, because (set! x y z) depends on the current
value of x, whereas (set! x y) ignores the current value.  Using set
(with no !) might be better.

The opaque records of R6RS and SRFI 99 extensions should be explicitly
excluded from this SRFI.

If SRFI-4 homogeneous vectors are supported by the implementation,
this SRFI should require that they be supported here too.

It would be easy to allow default arguments for all types of refs,
and I think that should be done, for convenience and uniformity.

Supporting a SRFI-17 setter for ref makes sense, but I think
(set! (car foo) bar quux) is even more confusing than (set! foo bar quux).

--
John Cowan          http://www.ccil.org/~cowan        xxxxxx@ccil.org
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