[R6RS] SYNTAX-CASE

[dyb at cs.indiana.edu]

> Why do you consider that its hard to use a unified matched? Could you give 
> me some hints? Is it because of the problem of keeping tracks of the location
> in the source files of the original s-expressions?

It's nothing deep, just that I don't believe we can come up with a unified
matcher that is as convenient for syntactic abstraction as syntax-case
while at the same time being appropriate for general pattern matching.
The difficulties are just those I laid out in my October 19 note.  If we
end up with something that doesn't work just as well as syntax-case for
syntactic abtraction, it won't replace syntax-case in actual use and we
will have failed to standardize on what people actually use.

Also, Given the distinctions among existing general-purpose matchers, I'm
also concerned that we would have trouble agreeing on any general-purpose
matcher, let alone one that is suitable for syntactic abstraction.

Kent