Re: ssax thread-safe? example

Hello!

	We have a couple of PLT Scheme experts around. Alas, they will
be away until Thursday. At present, I can venture only one guess: is
let*-values thread-safe? I know, on Bigloo, multiple-values use global
variables to pass extra values. That is perfectly OK in a
single-threaded mode: the second-class nature of multiple-values
guarantees that nothing will come between a producer and a
consumer. However, if a system decides to switch threads in-between,
the trouble is imminent.

	To verify, you may wish to globally search-and-replace
let*-values (it occurs only in SSAX.scm) with let*-values1 and values
with values1, which you can implement as

(define values1 list)

(define (call-with-values1 producer consumer)
  (apply consumer (producer)))

; Like let* but allowing for multiple-value bindings: SRFI-11
(define-syntax let*-values1
  (syntax-rules ()
    ((let*-values1 () . bodies) (begin . bodies))
    ((let*-values1 (((var) initializer) . rest) . bodies)
      (let ((var initializer))		; a single var optimization
	(let*-values1 rest . bodies)))
    ((let*-values1 ((vars initializer) . rest) . bodies)
      (call-with-values1 (lambda () initializer) ; the most generic case
	(lambda vars (let*-values1 rest . bodies))))))



	I'll ask the experts when they come back.

	Cheers,
	Oleg


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