Re: [Jscheme-user] Javadot constructor style vs Java setter raft style

[Timothy J. H. <tim...@ma...>]

Hi David and Ken,

On Tuesday, February 3, 2004, at 02:43 PM, Ken Anderson wrote:

> At 11:14 AM 2/3/2004 -0800, david wrote:
>> Thanks
>> It eventually came  back to me..
>> I just downloaded and installed the jetty based tutorial.
>> I may include this by in the linux distro I am working on.
>> If it's okay with you.
>
> Best to check with Tim.
Its OK with me, but I'm putting together a better version soon so you 
might
want to wait. (See below...) When do you want your next linux distro 
release to be?

>
>> I am thinking Jscheme and Mozilla/XUL  make a pretty good combination.
>> Is Anybody doing anything with this ?
It think it might be a good combination and no one that I know of is 
working on it....


>
> First i've heard about XUL.
I looked into it. Its sort of a JLIB-like approach to GUI building but 
using XML
rather than Scheme expressions.
          http://xul.sourceforge.net/
There are several versions in Java (basically XML parsers for this 
particular XML language)

For example,
    http://thinlet.sourceforge.net/calculator.html
Gives an example of a calculator applet where the GUI is given in XUL by

<panel gap="4" top="4" left="4">
   <textfield name="number1" columns="4" />
   <label text="+" />
   <textfield name="number2" columns="4" />
   <button text="=" action="calculate(number1.text, number2.text, 
result)" />
   <textfield name="result" editable="false" />
</panel>

The Java source that uses this XUL file is

package thinlet.demo;
import thinlet.*;

public class Calculator extends Thinlet {

   public Calculator() throws Exception {
     add(parse("calculator.xml"));
   }

   public static void main(String[] args) throws Exception {
     new FrameLauncher("Calculator", new Calculator(), 320, 240);
   }
}

   public void calculate(String number1, String number2, Object result) {
     try {
       int i1 = Integer.parseInt(number1);
       int i2 = Integer.parseInt(number2);
       setString(result, "text", String.valueOf(i1 + i2));
     } catch (NumberFormatException nfe) {
       getToolkit().beep();
     }
   }

In JScheme with JLIB we could do this as

(define (install applet)
   (define lib (jlib.Swing.load))

   ;; Layout and component properties
   (define G
    (let* ((H (java.util.Hashtable.))
          (L (lambda(name) (lambda(x) (.put H name x)))))
     (row
       (textfield "" 4 (L "number1"))
       (label "+")
       (textfield "" 4 (L "number2"))
       (button "=" (action (lambda(e) (calc H))))
       (textfield "" 4 (L "result") (lambda(x) (.setEditable x #f)))
       (button "beep" (action
(lambda(e) (.java.awt.Toolkit.beep
                      (.java.applet.Applet.getToolkit applet)))))
     )))

   ;; event handling
   (define (calc H)
     (tryCatch
       (writeexpr (.get H "result")
        (+ (readexpr (.get H "number1")) (readexpr (.get H "number2"))))
       (lambda(e) (.java.awt.Toolkit.beep
                      (.java.applet.Applet.getToolkit applet)))))

   (.add applet G)
)

But with a little macrology and mini-language building, we ought to
be able to get something even cleaner....
or... we could write a XUL->S-expression parser and then
evaluate the S-expression to get a JLIB widget....

You can try this example at the links below, but I didn't get the beep 
to work...
I'll have to look into it some other time (maybe I need 
getDefaultTooklit instead of getToolkit??)

http://tat.cs.brandeis.edu:8090/spr04/tjhickey/calc.scmapp to run the 
applet
http://tat.cs.brandeis.edu:8090/spr04/tjhickey/calc.scmV to see the 
"validated applet"
http://tat.cs.brandeis.edu:8090/spr04/tjhickey/calc.scm  to see the 
plain code (which is the only thing I actually wrote!)

>
> k
>
>
>
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