[ltk-user] ltk-tile make-instance 'button :command

[Everett Fuller]

Howdy Peter

I have to say, from the general style your code basically looks like
> the code I would write.
>

Makes sense, since it's your code that I'm copying, hehe.

- what lisp are you using, SBCL has pi defined as a constant?
>

I have both clisp 2.48 and sbcl 1.0.35 installed, and just discovered that
clisp also has pi predefined.  I started with clisp because it was already
included with slackware, and the logic of a slacker is:  if Pat thought it
was good enough, then it must be.  However, I have since learned that sbcl
compiles to machine code whereas clisp compiles to byte code, and even in
the ltk package, clisp can't do the "serve-event" stuff.  My goal is to
write code that does read-time conditionalization for clisp and sbcl, and to
use clisp when working on non-profit projects and sbcl when working on
commercial projects.

Thanks for this invaluable resource.  I've been trying out the different
widgets, and just tried the notebook instance, and am using it  in my
current endeavor of making a gui to help with the maintenance of my dns
server (i'm tired of manually creating and editing zone files by hand)...
hopefully everything will work and I won't be back here begging for
deliverance from my confusion.

Thanks again,

--Everett

On Tue, Apr 13, 2010 at 1:43 PM, Peter Herth <herth at peter-herth.de> wrote:

> Hi Everett,
>
> I have to say, from the general style your code basically looks like
> the code I would write.
> Just a few comments, none of them ltk related:
>
> - you set some variables, but never define them, rather use let*
> - what lisp are you using, SBCL has pi defined as a constant?
> - and the biggest one: DON'T use read on user input carelessly, try
> for example entering #.(do-msg "huch!") instead of a number and press
> calculate... read allows for evaluation of arbitrary lisp code.
>
> Of course, the dialog layout could be different, but thats just fiddling a
> bit
> with the options of pack...
>
> So the code could look like:
>
> (defun circularea ()
>  (with-ltk (:debug-tcl nil)
>    (wm-title *tk* "circularea")
>    (let* ((label-d (make-instance 'label
>                                   :text "A circle with a diameter of "))
>           (entry-d (make-instance 'entry
>                                   :text "0"))
>           (label-u (make-instance 'label
>                                   :text "units"))
>           (label-a (make-instance 'label
>                                   :text "has an area of "))
>           (label-r (make-instance 'label
>                                   :text "0"))
>           (label-su (make-instance 'label
>                                    :text "square units"))
>           (b (make-instance 'button
>                             :text "calculate"
>                             :command
>                             (lambda ()
>                                (let* ((diameter (let ((*read-eval* nil))
>                                                  (read-from-string
> (text entry-d))))
>                                      (radius (/ diameter 2))
>                                      (area (* pi (* radius radius))))
>                                  (setf (text label-r) area))))))
>      (pack label-d)
>      (pack entry-d)
>      (pack label-u)
>      (pack label-a)
>      (pack label-r)
>      (pack label-su)
>      (pack b) )))
>
>
> Peter
>
> _______________________________________________
> ltk-user site list
> ltk-user at common-lisp.net
> http://common-lisp.net/mailman/listinfo/ltk-user
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.common-lisp.net/pipermail/ltk-user/attachments/20100419/d0a1c93c/attachment.html>