Re: [Scheme-reports] Write procedure is not backwards compatible John Cowan (02 Jul 2012 00:22 UTC)

Re: [Scheme-reports] Write procedure is not backwards compatible John Cowan 02 Jul 2012 00:22 UTC

Marc Feeley scripsit:

> R7RS introduces a new output procedure called write-simple, which has
> the same semantics as the R5RS write procedure.  On the other hand,
> the R7RS write procedure handles shared structures differently than
> the R5RS.  For example :
>
>    (let ((x (list 1 2))) (write (list x x)))
>
>        displays ((1 2) (1 2)) in an R5RS system
>    and displays (#0=(1 2) #0#) in an R7RS system

R5RS leaves the output of `write` unspecified in such a case.  In actual
fact, it leaves the output of `(write (list 1 2))` unspecified as well.

--
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