Re: bug in pprint with circular lists in structures?

Sorry to reply to my own message, but I had posted this on
comp.lang.lisp as well, and only just recently got a response
suggesting that this is a bug, and not implementation specific
behavior.

So, should pprint respect *print-circle* ?

On 2/22/07, Taylor, Joshua <tayloj@rpi.edu> wrote:
> Hello all,
> I'm wondering if this is a bug. I'm not sure, as I'm having a hard time
> tracking down the inter-dependencies between the various
> *print-xxx*variables.
>
> In CLISP:
>
>
> [1]> (setf *print-circle* t)
> T
> [2]> (print '#1=(1 2 3 . #1#))
>
> #1=(1 2 3 . #1#)
> #1=(1 2 3 . #1#)
> [3]> (pprint '#1=(1 2 3 . #1#))
>
> #1=(1 2 3 . #1#)
>
> [4]> (defstruct foo l)
> FOO
> [5]> (print (make-foo :l '#1=(1 2 3 . #1#)))
>
> #S(FOO :L #1=(1 2 3 . #1#))
> #S(FOO :L #1=(1 2 3 . #1#))
> [6]> (pprint (make-foo :l '#1=(1 2 3 . #1#)))
>
> #S(FOO :L #1=(1 2 3 . #1#))
>
>
> But in Lispworks: (LWM 4.4.5):
>
> CL-USER 1 > (setf *print-circle* t)
> T
>
> CL-USER 2 > (print '#1=(1 2 3 . #1#))
>
> #1=(1 2 3 . #1#)
> #1=(1 2 3 . #1#)
>
> CL-USER 3 > (pprint '#1=(1 2 3 . #1#))
>
> #1=(1 2 3 . #1#)
>
> CL-USER 4 > (defstruct foo l)
> Foo
>
> CL-USER 5 > (print (make-foo :l '#1=(1 2 3 . #1#)))
>
> #S(Foo :L #1=(1 2 3 . #1#))
> #S(Foo :L #1=(1 2 3 . #1#))
>
> CL-USER 6 > (pprint (make-foo :l '#1=(1 2 3 . #1#)))
>
> ;; and then it hangs here until I break manually.
>
>
> I'm having a hard time determining what the behavior
> *should* be (if it's even specified), and whether or not
> there's a bug here, or if I should be doing something
> with set-pprint-dispatch, &c,
>
> Thanks!
>
>
> --
> =====================
> Joshua Taylor
> tayloj@rpi.edu
>
> "A lot of good things went down one time,
>      back in the goodle days."
>                John Hartford
>


-- 
=====================
Joshua Taylor
tayloj@rpi.edu

"A lot of good things went down one time,
     back in the goodle days."
               John Hartford