* Straight recursive fact prints in floating-point in org-babel but not in REPL
@ 2015-12-04 16:18 Brian Beckman
2015-12-06 3:13 ` Nick Dokos
0 siblings, 1 reply; 3+ messages in thread
From: Brian Beckman @ 2015-12-04 16:18 UTC (permalink / raw)
To: emacs-orgmode
Org-babel seems to print SLIME / SBCL bignums as floating point, at least in
this gist (please see
https://gist.github.com/rebcabin/f73cecd3c9b7da6218e9). I'd like to be able
to control whether bignums are printed out in full. Any advice for me?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Straight recursive fact prints in floating-point in org-babel but not in REPL
2015-12-04 16:18 Straight recursive fact prints in floating-point in org-babel but not in REPL Brian Beckman
@ 2015-12-06 3:13 ` Nick Dokos
2015-12-06 17:44 ` Charles C. Berry
0 siblings, 1 reply; 3+ messages in thread
From: Nick Dokos @ 2015-12-06 3:13 UTC (permalink / raw)
To: emacs-orgmode
Brian Beckman <bc.beckman@gmail.com> writes:
> Org-babel seems to print SLIME / SBCL bignums as floating point, at least in
> this gist (please see
> https://gist.github.com/rebcabin/f73cecd3c9b7da6218e9). I'd like to be able
> to control whether bignums are printed out in full. Any advice for me?
>
I think this happens because babel turns result strings into elisp
objects, using (read ...).
This has two consequences: the string has to be legal emacs-lisp (that
causes problems with e.g. scheme evaluators which return things like #t
and #f on which the elisp reader chokes; note also the conversion of
lisp-vector-to-list in ob-lisp.el which is done to avoid similar
problems); it also does violence to some strings as you have observed -
e.g. try
(read "123456789123456789123456789")
1.2345678912345679e+26
I'm not sure whether the (read ...) is required in order for babel
to work correctly, or whether it is a bug. I've wanted to look into
this for a while now (ever since Lawrence Bottorff reported the #t
problem with scheme), but I have not been able to find any time to
do so.
--
Nick
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Straight recursive fact prints in floating-point in org-babel but not in REPL
2015-12-06 3:13 ` Nick Dokos
@ 2015-12-06 17:44 ` Charles C. Berry
0 siblings, 0 replies; 3+ messages in thread
From: Charles C. Berry @ 2015-12-06 17:44 UTC (permalink / raw)
To: Nick Dokos; +Cc: emacs-orgmode
On Sat, 5 Dec 2015, Nick Dokos wrote:
> Brian Beckman <bc.beckman@gmail.com> writes:
>
>> Org-babel seems to print SLIME / SBCL bignums as floating point, at least in
>> this gist (please see
>> https://gist.github.com/rebcabin/f73cecd3c9b7da6218e9). I'd like to be able
>> to control whether bignums are printed out in full. Any advice for me?
>>
You can convert them to strings yourself and get ahead of the (read
...) issue Nick explains.
--8<---------------cut here---------------start------------->8---
#+BEGIN_SRC emacs-lisp
(defun fact (n)
(if (= 0 n)
1
(* n (fact (- n 1.0)))))
(format "%.0f" (fact 60))
#+END_SRC
#+RESULTS:
:
8320987112741391580056396102959641077457945541076708813599085350531187384917164032
--8<---------------cut here---------------end--------------->8---
HTH,
Chuck
>
> I think this happens because babel turns result strings into elisp
> objects, using (read ...).
>
> This has two consequences: the string has to be legal emacs-lisp (that
> causes problems with e.g. scheme evaluators which return things like #t
> and #f on which the elisp reader chokes; note also the conversion of
> lisp-vector-to-list in ob-lisp.el which is done to avoid similar
> problems); it also does violence to some strings as you have observed -
> e.g. try
>
> (read "123456789123456789123456789")
> 1.2345678912345679e+26
>
> I'm not sure whether the (read ...) is required in order for babel
> to work correctly, or whether it is a bug. I've wanted to look into
> this for a while now (ever since Lawrence Bottorff reported the #t
> problem with scheme), but I have not been able to find any time to
> do so.
>
> --
> Nick
>
>
>
Charles C. Berry Dept of Family Medicine & Public Health
cberry at ucsd edu UC San Diego / La Jolla, CA 92093-0901
http://famprevmed.ucsd.edu/faculty/cberry/
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2015-12-04 16:18 Straight recursive fact prints in floating-point in org-babel but not in REPL Brian Beckman
2015-12-06 3:13 ` Nick Dokos
2015-12-06 17:44 ` Charles C. Berry
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