[plt-scheme] about letrec and continuation : which behavior is correct ? and why ?

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Tue Aug 19 10:22:28 EDT 2008

At Tue, 19 Aug 2008 09:59:44 -0400, Matthias Felleisen wrote:
> Here is a proof that this must evaluate to #t.

Actually, on further investigation, I don't think that PLT Scheme's
`letrec' is supposed to behave that way, either. Your proof is treating
`letrec' like `let', right? That's exactly what MzScheme's optimizer is
incorrectly doing in this case.

So I'm now pretty sure that the right answer is #f for all of our
variations on `letrec', and I'll fix the optimizer.


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