Re: letrec bug

[Mikael Djurfeldt]

2008/10/28 Bill Schottstaedt <address@hidden>:
> I believe this shows a bug in letrec:
>
> guile> (let ((x 1)) (let ((x 32) (y x)) y))
> 1
> guile> (let ((x 1)) (letrec ((x 32) (y x)) y))
>
> Backtrace:
> In standard input:
>   2: 0* (let* ((x 1)) (letrec ((x 32) (y x)) y))
>   2: 1  (letrec ((x 32) (y x)) y)
>
> standard input:2:14: In expression (letrec (# #) y):
> standard input:2:14: Variable used before given a value: x
> ABORT: (unbound-variable)

Nope.

>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>."