Requested changes to R4RS

["Jonathan S. Shapiro" <shap@polya.stanford.edu>]

About the SYMBOL-VALUE mail.  I was wrong. Thinking about it, however,
has led me to the following question:  Does the specification require
that LOAD use READ? Should it?  Similarly, should READ be required to
be based on READ-CHAR and PEEK-CHAR?

Consider the problem of having a meta-language to describe concisely
something that has a routine expansion into Scheme, but the expansion
is much larger than the concise specification.  If the LOAD routine is
required to use READ, I could contemplate something like:

	(define (myload file)
	   (let ((standard-read read))
	     (set! read myread)
	     (load file)
	     (set! read standard-read)))

where myread does the translation before the interpreter gets a hold
of things.  We can argue about whether or not this is a good idea, but
I think that the standard should make it clear whether this usage can
be relied on or not.

Similarly READ/(READ-CHAR,PEEK-CHAR).  Consider the problem of
internationalizatoin.  It would be nice if I could re-implement
READ-CHAR on top of READ-BYTE to do, for example, Kanji characters.

More generally, there are several standard functions which are
logically implemented on top of more-primitive standard functions, but
the standard does not require any necessary relationship between them.
Should it?  I could argue this either way, and in a few cases, notably
READ and LOAD, I think it is highly desirable.

I would be interested in hearing other opinions.

Jon