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The order of evaluation of the expressions used to
initialize bindings in LET is explicitly left
unspecified in the Scheme standard, Section 4.2.2:
"Semantics: The <init>s are evaluated in the
current environment (in some unspecified order), ..."
This is not the case.
I think SRFI-LET should show the same side effects and results
whether multiple values are used or not. If not, srfi-let is not
compatible
with srfi-let itself, although it is compatible with r5rs-let.
> (define x 10)
>
(srfi-let ((a (begin (display "first") (set! x (+ x 1)) x))
(b c (values
(begin (display "second") (set! x 1) x)
(begin (display "third") (set! x 1000) x)))
(d (begin (display "end") (set! x (+ x 11)) x)))
(set! x 10)
(list a b c d))
secondthirdfirstend (1001 1 1000 1012)
>
(srfi-let ((a (begin (display "first") (set! x (+ x 1)) x))
(b (begin (display "second") (set! x 1) x))
(c (begin (display "third") (set! x 1000) x))
(d (begin (display "end") (set! x (+ x 11)) x)))
(set! x 10)
(list a b c d))
firstsecondthirdend (11 1 1000 1011)
>
(let ((a (begin (display "first") (set! x (+ x 1)) x))
(b (begin (display "second") (set! x 1) x))
(c (begin (display "third") (set! x 1000) x))
(d (begin (display "end") (set! x (+ x 11)) x)))
(set! x 10)
(list a b c d))
firstsecondthirdend (11 1 1000 1011)
--
Joo ChurlSoo