On Oct 7, 2006, at 4:23 PM, Aubrey Jaffer wrote:
> It is my understanding that LETREC* semantics can replace LETREC
> semantics in an R5RS implementation without breaking any behavior
> guaranteed by R5RS.
This understanding may be incorrect. Al Petrofsky has an expression
that can observe the difference between R5RS letrec and the common
implementation of letrec as letrec* (by using, surprise surprise,
call/cc). See the following thread:
http://groups.google.com/group/comp.lang.scheme/tree/browse_frm/
thread/141d47814c79776b/b646336450487157?rnum=1&q=Widespread+bug+
(arguably)+in+letrec+when+an+initializer+returns+twice&_done=%2Fgroup%
2Fcomp.lang.scheme%2Fbrowse_frm%2Fthread%2F141d47814c79776b%
2F93641d7d47af2858%3Flnk%3Dst%26q%3DWidespread+bug+(arguably)+in
+letrec+when+an+initializer+returns+twice%26rnum%3D1%
26#doc_93641d7d47af2858
-Felix Klock
Received on Sat Oct 07 2006 - 20:07:01 UTC