Re: Bug with letrec???

[Michael Livshin <mlivshin at bigfoot dot com>]

Lars Arvestad <arve@nada.kth.se> writes:

> NP> it seems that letrec is not working correct?! I thought this is the
> NP> standard behaviour according to RnRS? What is the difference between
> NP> letrec and let in this case?
> 
> It works correct. Here is from R5RS:
> 
>      One restriction on `letrec' is very important: it must be possible
>      to evaluate each <init> without assigning or referring to the
>      value of any <variable>.  If this restriction is violated, then it
>      is an error.  The restriction is necessary because Scheme passes
>      arguments by value rather than by name.  In the most common uses
>      of `letrec', all the <init>s are lambda expressions and the
>      restriction is satisfied automatically.

an interesting thing is that at least in Scsh and MzScheme letrec
works as Norbert expected.  but yes, per R5RS it doesn't have to.

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