if/else execution in elisp

if/else execution in elisp

[ken]

This should be simple.  It is in every other language I've ever used.  
Here's an if/else:

  (if (> lb 5)
      (setq hh (+ 2 hh)  lb (+ 4 lb))		; if true
	    (setq hh (+ 1 hh) lb (+ 3 lb))	; if false
	    )

What I'm trying to do should be obvious.  If not:

If lb is greater than 5, increment hh and lb by 2 and 4 respectively.
If not, increment hh and lb by 1 and 3 respectively.


Appreciated.

-- 
AMD crashes?  See http://cleveland.lug.net/~ken/amd-problem/.

Re: if/else execution in elisp

[Barry Margolin]

In article <mailman.1034973328.14861.help-gnu-emacs@gnu.org>,
ken  <ken@cleveland.lug.net> wrote:
>This should be simple.  It is in every other language I've ever used.  
>Here's an if/else:
>
>  (if (> lb 5)
>      (setq hh (+ 2 hh)  lb (+ 4 lb))		; if true
>	    (setq hh (+ 1 hh) lb (+ 3 lb))	; if false
>	    )
>
>What I'm trying to do should be obvious.  If not:
>
>If lb is greater than 5, increment hh and lb by 2 and 4 respectively.
>If not, increment hh and lb by 1 and 3 respectively.

It looks correct to me.  What's the problem you're having?

-- 
Barry Margolin, barmar@genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

Re: if/else execution in elisp

[ken]

Thanks for the vote of confidence.  I was starting to doubt reality.  
Here's the bigger fragment:

(defun testo-func ()
  (setq 
   zlist '(2 65535 3)			
   firsto (car zlist)
   segundo (car (cdr zlist))
   thirdo (cdr (cdr zlist)))

  (if (> segundo 44671)
      (setq firsto (+ 2 firsto)  segundo (- 44672 segundo))
    (setq firsto (+ 1 firsto) segundo (+ 20864 segundo))
    )
  (list firsto segundo thirdo)
  )

When I evaluate (test-func), I want to get (4 20863 3), but I'm getting
instead (4 -20863 (3)).  The hilarious part is that testo-func works 
just fine for a lot of setq'd values.  


I'm about to die laughing.  Please help it stop.


ken

-- 
AMD crashes?  See http://cleveland.lug.net/~ken/amd-problem/.

Spake Barry Margolin at 20:43 (UTC-0000) on Fri, 18 Oct 2002:

= In article <mailman.1034973328.14861.help-gnu-emacs@gnu.org>,
= ken  <ken@cleveland.lug.net> wrote:
= >This should be simple.  It is in every other language I've ever used.  
= >Here's an if/else:
= >
= >  (if (> lb 5)
= >      (setq hh (+ 2 hh)  lb (+ 4 lb))		; if true
= >	    (setq hh (+ 1 hh) lb (+ 3 lb))	; if false
= >	    )
= >
= >What I'm trying to do should be obvious.  If not:
= >
= >If lb is greater than 5, increment hh and lb by 2 and 4 respectively.
= >If not, increment hh and lb by 1 and 3 respectively.
= 
= It looks correct to me.  What's the problem you're having?
= 
= 

Re: if/else execution in elisp

[Ehud Karni]

On Sun, 20 Oct 2002 15:36:03 -0400 (EDT), ken <ken@cleveland.lug.net> wrote:
> 
> (defun testo-func ()
>   (setq 
>    zlist '(2 65535 3)			
>    firsto (car zlist)
>    segundo (car (cdr zlist))
>    thirdo (cdr (cdr zlist)))

This should be:
     thirdo (car (cdr (cdr zlist))))
> 
>   (if (> segundo 44671)
>       (setq firsto (+ 2 firsto)  segundo (- 44672 segundo))
The correct expression is:         segundo (- segundo 44672))

>     (setq firsto (+ 1 firsto) segundo (+ 20864 segundo))
>     )
>   (list firsto segundo thirdo)
>   )

Now it works as you expect.

I suggest the use of the `nth' built-in function (check its help)
for getting the nth element of a list, instead of `(car (cdr ...'

Ehud.


-- 
 Ehud Karni           Tel: +972-3-7966-561  /"\
 Mivtach - Simon      Fax: +972-3-7966-667  \ /  ASCII Ribbon Campaign
 Insurance agencies   (USA) voice mail and   X   Against   HTML   Mail
 http://www.mvs.co.il  FAX:  1-815-5509341  / \
 mailto:ehud@unix.mvs.co.il                  Better  Safe  Than  Sorry

Re: if/else execution in elisp

[Barry Margolin]

In article <mailman.1035149738.4225.help-gnu-emacs@gnu.org>,
Ehud Karni <ehud@unix.mvs.co.il> wrote:
>I suggest the use of the `nth' built-in function (check its help)
>for getting the nth element of a list, instead of `(car (cdr ...'

Or 'first', 'second', and 'third'.

-- 
Barry Margolin, barmar@genuity.net
Genuity, Woburn, MA
*** DON'T SEND TECHNICAL QUESTIONS DIRECTLY TO ME, post them to newsgroups.
Please DON'T copy followups to me -- I'll assume it wasn't posted to the group.

Re: if/else execution in elisp

[Miles Bader]

Barry Margolin <barmar@genuity.net> writes:
> >I suggest the use of the `nth' built-in function (check its help)
> >for getting the nth element of a list, instead of `(car (cdr ...'
> 
> Or 'first', 'second', and 'third'.

Those are not normally provided by elisp.

-Miles
-- 
自らを空にして、心を開く時、道は開かれる