jscheme-user — list for general users

Fwd: [Jscheme-user] jswebapp.zip: Where?

[Timothy J H. <tjh...@br...>]

Hi Joseph,

Thanks for the pointer!
It can be found at http://jscheme.sourceforge.net/jscheme/downloads
We recently updated the website and forgot to change those pointers....

Thanks,
---Tim---


On Feb 24, 2006, at 10:31 PM, Joseph Toman wrote:

> Hey,
>
> I just noticed that jswebapp.zip, or jscheme-webapp.zip, is not to be
> found at jscheme.sourceforge.net and there are a number of broken links
> pointing to it. Did it go away, or move somewhere else, or ... ?
>
>
> 					J. Toman
>
>
>
>
>
> -------------------------------------------------------
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[Jscheme-user] jswebapp.zip: Where?

[Joseph T. <to...@el...>]

Hey,

I just noticed that jswebapp.zip, or jscheme-webapp.zip, is not to be
found at jscheme.sourceforge.net and there are a number of broken links
pointing to it. Did it go away, or move somewhere else, or ... ?


					J. Toman

[Jscheme-user] jscheme servlets

[Geoffrey K. <ge...@kn...>]

I hope this is an easy question.  I've been writing JScheme servlets  
for a while, but using the Jetty server that comes with JScheme (bin/ 
make -server).  Since I have Sun's JWSDP (which includes Tomcat),  
Tomcat standalone, Geronimo (which includes Tomcat), an IDE which  
includes Tomcat, oh yes, and JBoss, which includes Tomcat, I'm trying  
to do some consolidation.  E.g., I'd like to deploy my JScheme  
servlets to Geronimo, and have Geronimo or its Tomcat find the right  
JScheme .jar to make the servets come up OK with minimal  
configuration and copying of files.  Has anyone else been down this  
road?

Geoffrey
--
Geoffrey S. Knauth | http://knauth.org/gsk

[Jscheme-user] Thanks for JScheme

[Marco B. <mar...@gm...>]

Hey there,

my name ist Marco Bakera and i am coming from germany. After trying to
get some simple Scheme Interpreter for Java and trying out Kawa and
SISC I got stuck with nearly the simplest things. That's why i just
want to thank you for such a great and simple approach you did with
JScheme.

I just had to say this. :)


Greetings from germany,
Marco.


PS
I hope you are still developing the library and will be R5RS compliant
in not so far distant future. ;)

--
,----[ /X\arco -- www.bakera.de ]----
|         (Y F) =3D (F (Y F))
`----[ www.bulb-publications.de ]----

[Jscheme-user] JScheme at work and play!

[Timothy J H. <tjh...@br...>]

Dear JScheme users,

It would be nice to add a back link page to the JScheme website that 
lists the ways in
which people are using JScheme (and includes links to those projects if 
possible).

If you have a moment to send a brief description of how you've been 
using JScheme,
I'll whip up a webpage containing all of your responses.

---Tim---


Some of my current uses are as follows:

User: Tim Hickey
Applications:

Teaching:
I teach JScheme to non-Science majors in the Introduction to Computer's 
class.
They learn how to write Scheme servlets as well as applets. All course 
management is done
using a JScheme server.
website: http://popper.cs-i.brandeis.edu:8080/classes/spr06/cs2a
We also have a student server that allows students to upload their own 
servlets using a webform:
website: http://popper.cs-i.brandeis.edu:8088/cs2a06


WebSites:
I maintain several websites using Scheme servlets.
http://www.cs.brandeis.edu the main CS web pages
http://4collegewomen.org  - a college women's health site
We use JScheme to maintain the development version and then use wget 
-kmp URL...
to make a static copy of the website which is then copied to the 
production server.


Groupware:
We are using a collaborative editor (grewpedit) which was written in 
JScheme
One of my PhD students is creating a Java version of the grewpedit tool 
based on the
Scheme code. We've found its quite easy to go to Java once you build 
the tool in Scheme.
website: http://groupscheme.sourceforge.net/grewpedit

Visualization:
We are building a series of visualization tools which allow one to view 
database queries as
2D images (for particular types of databases) with 1 pixel per returned 
record. These tools are
mostly JScheme, but use auxilliary classes to handle the inner loops 
(e.g. transforming the
results of the database query to the pixels of an image), while JScheme 
is used for all of the
GUI building, mouse-handling, etc. We haven't released this code 
publicly yet....

[Jscheme-user] Website update

[Timothy J H. <tjh...@br...>]

Dear JScheme users,

The JScheme website has been upgraded by our new JScheme developer, 
Kyle Burton
(mortis at users.sourceforge.net). The website now provides downloads 
of JScheme 7.2
using the sourceforge download server.  Many thanks to Kyle for 
volunteering to refresh
the website (which was indeed sorely out of date!)

Best,
--Tim---

Re: [Jscheme-user] Accessing command line arguments?

[Timothy J H. <tjh...@br...>]

On Jan 23, 2006, at 10:04 PM, Kyle R. Burton wrote:

> I see that the arguments to main in jscheme.REPL are handled in =20
> various ways - as files to be loaded, as scheme expressions, or with =20=

> support for a -main proc-name arg1 ..., but is there a way of passing =20=

> through command line arguments so that they can be accessed by the =20
> scheme code being executed?

You can use the -main commandline argument which expects the next =20
string to be a Scheme procedure P
and it then grabs the remaining strings and bundles them into an array =20=

of Strings, L.
It then calls the Scheme procedure P on L.

For example, suppose that testing.scm is the following program

(define (testing L)
   (display (.getClass L))
   (newline)

   (display
     (map
       (lambda(x)
          (list x (.getClass x)))
       (array->list L)))
   (newline)
)

Then we can invoke jscheme and pass command line args to the testing =20
procedure
as follows:

     % java -cp ~/lib/jscheme.jar jscheme.REPL test.scm -main testing 1 =20=

2 3
     class [Ljava.lang.String;
     ((1 class java.lang.String) (2 class java.lang.String) (3 class =20
java.lang.String))

Is this what you are looking for?

Best,
---Tim---



>
> I'd like to use JScheme to create some command line utilities.=A0 To =
do =20
> so I need access to command line arguments, and stdin, stdout and =20
> stderr (the last three appear to be available as System.in , =20
> System.out and System.err, unless there is some JScheme replacement =20=

> for them that I'm not aware of...).
>
> Thanks,
>
> Kyle
>
> -- =20
> =
-----------------------------------------------------------------------=20=

> -------
> Wisdom and Compassion are inseparable.
> =A0=A0=A0=A0=A0=A0=A0=A0-- Christmas Humphreys
> kyl...@gm...=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=
=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0http://=20
> www.neverlight.com/~mortis
> =
-----------------------------------------------------------------------=20=

> -------

[Jscheme-user] Accessing command line arguments?

[Kyle R. B. <kyl...@gm...>]

I see that the arguments to main in jscheme.REPL are handled in various way=
s
- as files to be loaded, as scheme expressions, or with support for a -main
proc-name arg1 ..., but is there a way of passing through command line
arguments so that they can be accessed by the scheme code being executed?

I'd like to use JScheme to create some command line utilities.  To do so I
need access to command line arguments, and stdin, stdout and stderr (the
last three appear to be available as System.in, System.out and System.err,
unless there is some JScheme replacement for them that I'm not aware of...)=
.

Thanks,

Kyle

--
---------------------------------------------------------------------------=
---
Wisdom and Compassion are inseparable.
        -- Christmas Humphreys
kyl...@gm...
http://www.neverlight.com/~mortis
---------------------------------------------------------------------------=
---

Re: [Jscheme-user] Testing if a symbol is bound?

[Michael T. <mt...@bb...>]

Hmmm - thanks.  I think I'm going to stick to my definition:
(define (bound? symbol) (.isDefined symbol))
even though performance isn't much of an issue in the cases I want to 
use it.

I guess the followup question ought to be "How do I unbind a symbol?" 
but not only is this a hairier problem, but I don't really require an 
answer... ;-)

Cheers,
    -mik

Timothy J Hickey wrote:

> Hi mik,
>
> On Jan 10, 2006, at 3:10 PM, Michael Thome wrote:
>
>>  What is the "proper" way to test to see if a symbol is bound?
>
> There is no proper way, as far as I can tell.
>
>>
>>  I was expecting something like (bound? 'foo).
>
> If you have created a scheme environment using the jscheme.JScheme 
> constructor,
> then there is an isDefined method which tests whether a symbol is 
> defined in that interpreter,
> e.g.
>
>> [Timothy-Hickeys-Computer:~/Research/Software/jscheme] tim% java -jar 
>> lib/jscheme.jar
>> JScheme 7.2 (1/10/06 8:55 AM) http://jscheme.sourceforge.net
>> > (define js (jscheme.JScheme.))  ;; create a new scheme interpreter
>> $1 = jscheme.JScheme@5db13f
>>
>> > (.eval js '(define x 1))   ;; evaluate a define in that interpreter
>> $2 = 1
>>
>> > (.isDefined js "x")   ;; check to see if the symbol corresponding 
>> to the string "x" is defined in that interpreter
>> $3 = #t
>>
>> > (.isDefined js "y")  ;; notice that "y" is not defined
>> $4 = #f
>>
>> > (.isDefined 'x)  ;; also notice that 'x is not defined in the 
>> toplevel Scheme environment, only in js
>> $5 = #f
>>
>> > (.eval js 'x)  ;; we can get the value of 'x in js using eval 
>> again....
>> $6 = 1
>>
>
> If you want to check whether a symbol is defined in the toplevel then 
> (.isDefined 'foo) works fine.
> You could also use a macro with tryCatch  to test for defined-ness 
> without having to quote the symbol...
>
>> > (tryCatch (begin x #t) (lambda(e) #f))
>> $7 = #f
>>
>> > (define-macro (isDefined s) `(tryCatch (begin ,s #t) (lambda(e) #f)))
>> $8 = (macro isDefined (s)...)
>>
>> > (isDefined sin)
>> $9 = #t
>>
>> > (isDefined sine)
>> $10 = #f
>
>
>
> I like the try/Catch approach better because the (.isDefined 'x) 
> relies on the implementation of the Symbol.java class
> in the jsint package, which could conceivably change at some point, 
> whereas the tryCatch approach relies only on
> the syntax of macros and tryCatch and the fact that evaluating an 
> undefined symbol generates an exception....
> But, using (.isDefined 'foo) is ten times faster then the tryCatch 
> approach  ...
>
>>
>> > (time (isDefined foo) 100000)
>> $10 = (#f (2929 msec) (367880 bytes))
>>
>> > (time (.isDefined 'foo) 100000)
>> $11 = (#f (211 msec) (135856 bytes))
>
>
> Does that help??
>
> Best,
> ---Tim---
>

Re: [Jscheme-user] Testing if a symbol is bound?

[Geoffrey K. <ge...@kn...>]

Good question.  MIT/GNU Scheme has:

procedure: environment-reference-type environment symbol

Returns a symbol describing the reference type of symbol in  
environment or one of its ancestor environments.   The result is one  
of the following:

normal - means symbol is a variable binding with a normal value.
unassigned - means symbol is a variable binding with no value.
macro - means symbol is a keyword binding.
unbound - means symbol has no associated binding.

http://www.gnu.org/software/mit-scheme/documentation/scheme_14.html

Geoffrey
--
Geoffrey S. Knauth | http://knauth.org/gsk


On Jan 10, 2006, at 16:42, Timothy J Hickey wrote:

> Hi mik,
>
> On Jan 10, 2006, at 3:10 PM, Michael Thome wrote:
>>  What is the "proper" way to test to see if a symbol is bound?
> There is no proper way, as far as I can tell.
>>
>>  I was expecting something like (bound? 'foo).
> If you have created a scheme environment using the jscheme.JScheme  
> constructor,
> then there is an isDefined method which tests whether a symbol is  
> defined in that interpreter,
> e.g.
>
>> [Timothy-Hickeys-Computer:~/Research/Software/jscheme] tim% java - 
>> jar lib/jscheme.jar
>> JScheme 7.2 (1/10/06 8:55 AM) http://jscheme.sourceforge.net
>> > (define js (jscheme.JScheme.))  ;; create a new scheme interpreter
>> $1 = jscheme.JScheme@5db13f
>>
>> > (.eval js '(define x 1))   ;; evaluate a define in that interpreter
>> $2 = 1
>>
>> > (.isDefined js "x")   ;; check to see if the symbol  
>> corresponding to the string "x" is defined in that interpreter
>> $3 = #t
>>
>> > (.isDefined js "y")  ;; notice that "y" is not defined
>> $4 = #f
>>
>> > (.isDefined 'x)  ;; also notice that 'x is not defined in the  
>> toplevel Scheme environment, only in js
>> $5 = #f
>>
>> > (.eval js 'x)  ;; we can get the value of 'x in js using eval  
>> again....
>> $6 = 1
>>
>
> If you want to check whether a symbol is defined in the toplevel  
> then (.isDefined 'foo) works fine.
> You could also use a macro with tryCatch  to test for defined-ness  
> without having to quote the symbol...
>
>> > (tryCatch (begin x #t) (lambda(e) #f))
>> $7 = #f
>>
>> > (define-macro (isDefined s) `(tryCatch (begin ,s #t) (lambda(e)  
>> #f)))
>> $8 = (macro isDefined (s)...)
>>
>> > (isDefined sin)
>> $9 = #t
>>
>> > (isDefined sine)
>> $10 = #f
>
>
> I like the try/Catch approach better because the (.isDefined 'x)  
> relies on the implementation of the Symbol.java class
> in the jsint package, which could conceivably change at some point,  
> whereas the tryCatch approach relies only on
> the syntax of macros and tryCatch and the fact that evaluating an  
> undefined symbol generates an exception....
> But, using (.isDefined 'foo) is ten times faster then the tryCatch  
> approach  ...
>
>>
>> > (time (isDefined foo) 100000)
>> $10 = (#f (2929 msec) (367880 bytes))
>>
>> > (time (.isDefined 'foo) 100000)
>> $11 = (#f (211 msec) (135856 bytes))
>
> Does that help??
>
> Best,
> ---Tim---

Re: [Jscheme-user] Testing if a symbol is bound?

[Timothy J H. <tjh...@br...>]

Hi mik,

On Jan 10, 2006, at 3:10 PM, Michael Thome wrote:
>  What is the "proper" way to test to see if a symbol is bound?
There is no proper way, as far as I can tell.
>
>  I was expecting something like (bound? 'foo).
If you have created a scheme environment using the jscheme.JScheme 
constructor,
then there is an isDefined method which tests whether a symbol is 
defined in that interpreter,
e.g.

> [Timothy-Hickeys-Computer:~/Research/Software/jscheme] tim% java -jar 
> lib/jscheme.jar
> JScheme 7.2 (1/10/06 8:55 AM) http://jscheme.sourceforge.net
> > (define js (jscheme.JScheme.))  ;; create a new scheme interpreter
> $1 = jscheme.JScheme@5db13f
>
> > (.eval js '(define x 1))   ;; evaluate a define in that interpreter
> $2 = 1
>
> > (.isDefined js "x")   ;; check to see if the symbol corresponding to 
> the string "x" is defined in that interpreter
> $3 = #t
>
> > (.isDefined js "y")  ;; notice that "y" is not defined
> $4 = #f
>
> > (.isDefined 'x)  ;; also notice that 'x is not defined in the 
> toplevel Scheme environment, only in js
> $5 = #f
>
> > (.eval js 'x)  ;; we can get the value of 'x in js using eval 
> again....
> $6 = 1
>

If you want to check whether a symbol is defined in the toplevel then 
(.isDefined 'foo) works fine.
You could also use a macro with tryCatch  to test for defined-ness 
without having to quote the symbol...

> > (tryCatch (begin x #t) (lambda(e) #f))
> $7 = #f
>
> > (define-macro (isDefined s) `(tryCatch (begin ,s #t) (lambda(e) #f)))
> $8 = (macro isDefined (s)...)
>
> > (isDefined sin)
> $9 = #t
>
> > (isDefined sine)
> $10 = #f


I like the try/Catch approach better because the (.isDefined 'x) relies 
on the implementation of the Symbol.java class
in the jsint package, which could conceivably change at some point, 
whereas the tryCatch approach relies only on
the syntax of macros and tryCatch and the fact that evaluating an 
undefined symbol generates an exception....
But, using (.isDefined 'foo) is ten times faster then the tryCatch 
approach  ...

>
> > (time (isDefined foo) 100000)
> $10 = (#f (2929 msec) (367880 bytes))
>
> > (time (.isDefined 'foo) 100000)
> $11 = (#f (211 msec) (135856 bytes))

Does that help??

Best,
---Tim---

[Jscheme-user] Testing if a symbol is bound?

[Michael T. <mt...@bb...>]

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content="text/html;charset=ISO-8859-1" http-equiv="Content-Type">
  <title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
What is the "proper" way to test to see if a symbol is bound?<br>
<br>
I was expecting something like (bound? 'foo).<br>
<br>
I've been using (.isDefined 'foo) but surely there is something
better...<br>
<br>
Thanks,<br>
&nbsp;&nbsp;&nbsp; mik<br>
<div class="moz-signature">-- <br>
<table cellpadding="0" cellspacing="0" width="100%">
  <tbody>
    <tr>
      <td>
      <font color="#808080" size="2"><b>Michael Thome</b></font><br>
      <font color="#8f8fff" size="2">BBN Technologies</font>&nbsp;<font
 color="#808080" size="2">10 Moulton St, Cambridge MA 02138 USA</font><br>
      <font color="#808080" size="2">phone: +1 617 873 1853</font><br>
      </td>
    </tr>
  </tbody>
</table>
</div>
</body>
</html>

Re: [Jscheme-user] (reset)

[Timothy J H. <tjh...@br...>]

On Dec 13, 2005, at 6:05 PM, bor...@ko... wrote:
> It should be very easy to write one since the instance of the 
> interpreter
> is accessible so cleaning up the symbol table and reinstantiating the
> classloader, and perhaps a few other things, does it. I wrote some code
> for that at some point, but I don't have with me.
I don't have any code available right now for a reset, but I'll look 
into it.
It would be a good exercise in keeping track of the JScheme state!

---Tim---
>
> Boris
>
>> Every so often I can't remember what I've loaded, reloaded, imported,
>> etc.  I usually kill the JScheme and start anew.  Not a big deal, but
>> I was wondering if there is a (reset) capability.  Ideally it would
>> put me back where I started.
>>
>> Geoffrey
>> --
>> Geoffrey S. Knauth | http://knauth.org/gsk
>>
>>
>>
>>
>> -------------------------------------------------------
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>>
>
>
>
>
> -------------------------------------------------------
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Re: [Jscheme-user] (reset)

[<bor...@ko...>]

It should be very easy to write one since the instance of the interpreter
is accessible so cleaning up the symbol table and reinstantiating the
classloader, and perhaps a few other things, does it. I wrote some code
for that at some point, but I don't have with me.

Boris

> Every so often I can't remember what I've loaded, reloaded, imported,
> etc.  I usually kill the JScheme and start anew.  Not a big deal, but
> I was wondering if there is a (reset) capability.  Ideally it would
> put me back where I started.
>
> Geoffrey
> --
> Geoffrey S. Knauth | http://knauth.org/gsk
>
>
>
>
> -------------------------------------------------------
> This SF.net email is sponsored by: Splunk Inc. Do you grep through log
> files
> for problems?  Stop!  Download the new AJAX search engine that makes
> searching your log files as easy as surfing the  web.  DOWNLOAD SPLUNK!
> http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click
> _______________________________________________
> Jscheme-user mailing list
> Jsc...@li...
> https://lists.sourceforge.net/lists/listinfo/jscheme-user
>

[Jscheme-user] (reset)

[Geoffrey K. <ge...@kn...>]

Every so often I can't remember what I've loaded, reloaded, imported,  
etc.  I usually kill the JScheme and start anew.  Not a big deal, but  
I was wondering if there is a (reset) capability.  Ideally it would  
put me back where I started.

Geoffrey
--
Geoffrey S. Knauth | http://knauth.org/gsk

RE: [Jscheme-user] Help interpreting a stack trace

[Borislav I. <bor...@ko...>]

Hi Tim,

After a few evenings of struggle, I think I found where the problem
comes from. I was thrown off by the fact that the same application
works, successfully deployed for over 2 years now. Here is the issue:
the null/empty pair in Jscheme is represented by the static final
Pair.EMPTY which has both first and rest assigned to itself. The method
'isEmpty' simply compares 'this == Pair.EMPTY' instead of 'this == first
== rest" (doesn't look like it's possible in Jscheme to construct such a
pair). Now, the problem is when I serializes a Pair into a DB blob and
then deserialize it. The deserialized object looks exactly like
Pair.EMPTY, but it's not one and the same Java reference.

So, I found out that previous version of Jscheme had a Pair.readResolve
method that specifically dealed with the empty pair. Is there any
particular reason why this method was removed from later versions?

Thanks,
Boris


| -----Original Message-----
| From: Timothy J Hickey [mailto:tjh...@br...] 
| Sent: Wednesday, December 07, 2005 7:10 AM
| To: Borislav Iordanov
| Subject: Re: [Jscheme-user] Help interpreting a stack trace
| 
| 
| Hi Boris,
| 
|     It looks like the stack overflow occurs inside the 
| iterate call, but its hard to tell. If you send me the source 
| code I might be able to help you find it.... Typically this 
| will happen with a non-tail-call recursion as the Java stack 
| is not very deep...
| 
| Best,
| ---Tim---
| 
| On Dec 7, 2005, at 12:14 AM, Borislav Iordanov wrote:
| 
| > Hello,
| >
| > I'm trying to track down a stack overflow in a Jscheme code I wrote
| > some
| > time ago. Can anyone help me with the meaning of the following stack
| > trace:
| >
| > (heat-it image-graphics (get-polygons-for-coordinate (.get 
| radials i 
| > )(.get stages j ))(get-signal-for-region i j insitu-result 
| )max-signal
| > )
| >   j = 3
| >   stages = [Stage 4, Stage 3, Stage 2, Stage 1]
| >   applicable = [Stage 1]
| >   stage-loop = {jsint.Closure ??[3] (j stages applicable)}
| >   i = 0
| >   radials = [Columella, Cortex, Endo, Endo+Cortex,
| > Epidermis(atrichoblasts), Lat.root cap, Pericycle, Phloem, St...
| >   radial-loop = {jsint.Closure ??[2] (i radials)}
| >   max-signal = 527.924F
| >   image-graphics =
| > 
| sun.java2d.SunGraphics2D[font=java.awt.Font[family=Dialog,name
| =Dialog,s 
| > t
| > yle=plain,size=12],color=jav...
| >   image-encoder = sun.awt.image.codec.JPEGImageEncoderImpl@39452f
| >   insitu-result = 
| org.pamweb.ui.ticl.model.MySQLTableModel$Row@1ed13da
| >   session = 
| org.apache.catalina.session.StandardSessionFacade@1b25a82
| >   request = org.apache.coyote.tomcat4.CoyoteRequestFacade@541b02
| >   out = org.apache.coyote.tomcat4.CoyoteOutputStream@1b94ea2
| >
| >   ====================================
| >
| > (iterate radial-polygons {jsint.Closure ??[1] 
| (radial-point-list)} ) 
| > Error in BacktraceException.printStackTrace:
| > java.lang.StackOverflowError
| > Error in BacktraceException.printStackTrace:
| > java.lang.StackOverflowError
| > Error in BacktraceException.printStackTrace:
| > java.lang.StackOverflowError
| >
| > Specifically, should I assume that the stack overflow 
| occurs somewhere 
| > with the (iterate radial-polygons ...) call?
| >
| > Thanks,
| > Boris
| >
| >
| >
| > -------------------------------------------------------
| > This SF.net email is sponsored by: Splunk Inc. Do you grep 
| through log
| > files
| > for problems?  Stop!  Download the new AJAX search engine that makes
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| > _______________________________________________
| > Jscheme-user mailing list
| > Jsc...@li...
| > https://lists.sourceforge.net/lists/listinfo/jscheme-user
| 

[Jscheme-user] 6.1 on the website

[Kyle R. B. <kyl...@gm...>]

I was having issues with the jar on the jscheme.sf.net site and jdk1.5
so I checked out of CVS.  The CVS version reports the version as 7.2.=20
The download link (and latest released file) is a bit out of date.

How difficult is it to update the main page?

Does the project need a 'lackey' to help with this kind of maintenance?


Thanks,

Kyle

--
---------------------------------------------------------------------------=
---
Wisdom and Compassion are inseparable.
        -- Christmas Humphreys
kyl...@gm...                          =20
http://www.neverlight.com/~mortis
---------------------------------------------------------------------------=
---

[Jscheme-user] Help interpreting a stack trace

[Borislav I. <bor...@ko...>]

Hello,

I'm trying to track down a stack overflow in a Jscheme code I wrote some
time ago. Can anyone help me with the meaning of the following stack
trace:

(heat-it image-graphics (get-polygons-for-coordinate (.get radials i
)(.get stages j ))(get-signal-for-region i j insitu-result )max-signal )
  j = 3
  stages = [Stage 4, Stage 3, Stage 2, Stage 1]
  applicable = [Stage 1]
  stage-loop = {jsint.Closure ??[3] (j stages applicable)}
  i = 0
  radials = [Columella, Cortex, Endo, Endo+Cortex,
Epidermis(atrichoblasts), Lat.root cap, Pericycle, Phloem, St...
  radial-loop = {jsint.Closure ??[2] (i radials)}
  max-signal = 527.924F
  image-graphics =
sun.java2d.SunGraphics2D[font=java.awt.Font[family=Dialog,name=Dialog,st
yle=plain,size=12],color=jav...
  image-encoder = sun.awt.image.codec.JPEGImageEncoderImpl@39452f
  insitu-result = org.pamweb.ui.ticl.model.MySQLTableModel$Row@1ed13da
  session = org.apache.catalina.session.StandardSessionFacade@1b25a82
  request = org.apache.coyote.tomcat4.CoyoteRequestFacade@541b02
  out = org.apache.coyote.tomcat4.CoyoteOutputStream@1b94ea2

  ====================================

(iterate radial-polygons {jsint.Closure ??[1] (radial-point-list)} )
Error in BacktraceException.printStackTrace:
java.lang.StackOverflowError
Error in BacktraceException.printStackTrace:
java.lang.StackOverflowError
Error in BacktraceException.printStackTrace:
java.lang.StackOverflowError

Specifically, should I assume that the stack overflow occurs somewhere
with the (iterate radial-polygons ...) call?

Thanks,
Boris

[Jscheme-user] Reminder: Scheme UK Meeting: 7 December 2005

[Noel W. <noe...@ya...>]

Scheme UK Meeting: 7 December 2005

The next meeting of the Scheme UK user's group will be held
on 7 December 2005 from 7pm till we leave for the
pub.  The meeting will take place at the offices of LShift
(see http://www.lshift.net/contact.html for directions).
This meeting will be held in conjuction with UK Lispers.

Shriram Krishnamurthi: Verification and Change-Impact
Analysis of Access-Control Policies

Sensitive data are increasingly available on-line through
the Web and other distributed protocols. This heightens the
need to carefully control access to data. Control means not
only preventing the leakage of data but also permitting
access to necessary information. Indeed, the same datum is
often treated differently depending on context.

System designers create policies to express conditions on
the access to data. To reduce source clutter and improve
maintenance, developers increasingly use domain-specific,
declarative languages to express these policies. In turn,
administrators need to analyze policies relative to
properties, and to understand the effect of policy changes
even in the absence of properties.

This talk will discuss Margrave, a software suite for
analyzing role-based access-control policies. Margrave
includes a verifier that analyzes policies written in the
XACML language, translating them into a form of
decision-diagram to answer queries. It also provides
semantic differencing information between versions of
policies. Margrave is, of course, implemented in PLT
Scheme.

(Joint work with Kathi Fisler, Leo A. Meyerovich and
Michael
Carl Tschantz)


=========================================================

Scheme UK is a UK based group of people interested in the
Scheme programming language in particular, and advanced
programming languages in general.  We are interested in
both practical and theoretic aspects.  We meet on the
first Wednesday of each month.  Newcomers are welcome.

For more details see:

  http://schematics.sourceforge.net/scheme-uk/

Email: noelwelsh <at> yahoo <dot> com   noel <at> untyped <dot> com
AIM: noelhwelsh
Blogs: http://monospaced.blogspot.com/  http://www.untyped.com/untyping/


		
__________________________________________
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[Jscheme-user] Re: [Sisc-users] SISC vs Kawa

[Timothy J H. <tjh...@br...>]

On Nov 17, 2005, at 12:23 AM, Victor Rodriguez wrote:

> Hello Tim!
>
> 2005/11/16, Timothy John Hickey <ti...@cs...>:
> ..
>> Another option you can consider is JScheme (jscheme.sourceforge.net).
>> It has a very nice approach to Java integration (the javadot =
notation)
>> and is reasonably fast (of course as a JScheme developer I'm biased!)
>
> Ah! If only I had more time,
Time always is the problem!!
> I would take the time to look at all the
> alternatives. Nonetheless, I will try to take a look to JScheme. I had
> read about the dot notation before, and the website makes a good
> impression. (As does your recommendation!)
>
>> We've used it extensively in several projects, including a groupware
>> system
>>      http://groupscheme.sourceforge.net/grewpedit/
>> that I use every day in my lecture class. This program allows a dozen=20=

>> or
>> students with laptops in class to connect to my server and to jointly
>> coedit Java programs (without locking). I only mention this to point
>> out that
>> for this type of application, JScheme is certainly fast enough as =
most
>> of the computation is limited by human typing speed. (We are actually
>> rewriting grewpedit in Java so as to encourage Java developers to use
>> the
>> resulting collaborative editing library, while still allows Scheme
>> applications
>> to be developed using that code....)
>
> What a pity.. I take it then JScheme cannot "expose" Java classes, as
> D. Boucher mentions Kawa does?
We've made a try at exposing Java classes using the "dclass" package,
but it still needs some work.  One advantage of rewriting it in Scheme=20=

is
that we can then do a comparison and see exactly what the performance
gains are (or are not).  We'll probably rewrite it again in Scheme=20
(probably
using the dclass approach).  It will be interesting to see whether the=20=

project
gets more exposure after the Java rewrite since it will be packaged in=20=

a way
that is familiar to more people.....



>> JScheme is *not* R5RS compliant. It doesn't support full=20
>> continuations,
>> it doesn't support any SRFIs.  It is however a nice environment for
>> writing
>> Scheme code that interacts closely with Java code. It does have Last
>> Call
>> Optimization however.
>
> Do you mean tail recursion elimination?
Yes.

>
>> Anyway, just thought you might like some other ideas, but I didn't=20
>> want
>> to
>> clog up the SISC discussion list.
>
> Thanks a lot for taking the time to write to me, I really appreciate=20=

> it!
My pleasure.  Although there isn't much activity in JScheme development=20=

these
days, thats mainly due to the fact that it is in a pretty good place.=20
For my own
development, its got just about all the features I need....

Best wishes,
---Tim---


>
> Best Regards,
>
> Victor Rodriguez
>
>> Best wishes,
>> ---Tim---
>>
>>
>>
>>
>> On Nov 16, 2005, at 12:34 PM, Victor Rodriguez wrote:
>>
>>> 2005/11/15, Chris Dean <ct...@so...>:
>>>> [Let's assume this is not a troll.]
>>>
>>> Funny how a question like this can make people suspicious! :-)
>>>
>>> [snip]
>>>> You could also abandon Java and just use mzscheme.
>>>
>>> I can certainly abandon Java for personal projects, but the place I
>>> work is a Java shop for the foreseeable future.  Fortunately, SISC
>>> could be a way to introduce Scheme without giving up Java, and so I=20=

>>> am
>>> hopeful.
>>>
>>> I realize know that I left out the most important question to =
realize
>>> this goal: which has better Java integration, SISC or Kawa?
>>>
>>>> =46rom the responses so far, Kawa seems to have an advantage. The=20=

>>>> truth
>>> is, I'm attracted to SISC, since it supports more features, such as
>>> continuations, and from what I have seen so far (very little), Java
>>> integration seems to be easy.
>>>
>>> By the way, since you mention it, l do not necessarily have to use a
>>> Java-based Scheme for other projects. Is there a Scheme=20
>>> implementation
>>> with a nice library for doing GUI applications? (in Windows, Linux,
>>> both?)
>>>
>>> Thanks,
>>>
>>> Victor Rodriguez.
>>>
>>>
>>> -------------------------------------------------------
>>> This SF.Net email is sponsored by the JBoss Inc.  Get Certified =
Today
>>> Register for a JBoss Training Course.  Free Certification Exam
>>> for All Training Attendees Through End of 2005. For more info visit:
>>> http://ads.osdn.com/?ad_idv28&alloc_id=16845&op=3Dclick
>>> _______________________________________________
>>> Sisc-users mailing list
>>> Sis...@li...
>>> https://lists.sourceforge.net/lists/listinfo/sisc-users
>>
>>

[Jscheme-user] Re: [Sisc-users] SISC vs Kawa

[Timothy J. H. <ti...@cs...>]

Hi Victor,

I've been lurking on the sisc list listening to the SISC vs Kawa debate.

Another option you can consider is JScheme (jscheme.sourceforge.net).
It has a very nice approach to Java integration (the javadot notation)
and is reasonably fast (of course as a JScheme developer I'm biased!)

We've used it extensively in several projects, including a groupware=20
system
     http://groupscheme.sourceforge.net/grewpedit/
that I use every day in my lecture class. This program allows a dozen or
students with laptops in class to connect to my server and to jointly
coedit Java programs (without locking). I only mention this to point=20
out that
for this type of application, JScheme is certainly fast enough as most
of the computation is limited by human typing speed. (We are actually
rewriting grewpedit in Java so as to encourage Java developers to use=20
the
resulting collaborative editing library, while still allows Scheme=20
applications
to be developed using that code....)

JScheme is *not* R5RS compliant. It doesn't support full continuations,
it doesn't support any SRFIs.  It is however a nice environment for=20
writing
Scheme code that interacts closely with Java code. It does have Last=20
Call
Optimization however.

Anyway, just thought you might like some other ideas, but I didn't want=20=

to
clog up the SISC discussion list.

Best wishes,
---Tim---




On Nov 16, 2005, at 12:34 PM, Victor Rodriguez wrote:

> 2005/11/15, Chris Dean <ct...@so...>:
>> [Let's assume this is not a troll.]
>
> Funny how a question like this can make people suspicious! :-)
>
> [snip]
>> You could also abandon Java and just use mzscheme.
>
> I can certainly abandon Java for personal projects, but the place I
> work is a Java shop for the foreseeable future.  Fortunately, SISC
> could be a way to introduce Scheme without giving up Java, and so I am
> hopeful.
>
> I realize know that I left out the most important question to realize
> this goal: which has better Java integration, SISC or Kawa?
>
>> =46rom the responses so far, Kawa seems to have an advantage. The =
truth
> is, I'm attracted to SISC, since it supports more features, such as
> continuations, and from what I have seen so far (very little), Java
> integration seems to be easy.
>
> By the way, since you mention it, l do not necessarily have to use a
> Java-based Scheme for other projects. Is there a Scheme implementation
> with a nice library for doing GUI applications? (in Windows, Linux,
> both?)
>
> Thanks,
>
> Victor Rodriguez.
>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by the JBoss Inc.  Get Certified Today
> Register for a JBoss Training Course.  Free Certification Exam
> for All Training Attendees Through End of 2005. For more info visit:
> http://ads.osdn.com/?ad_idv28&alloc_id=16845&op=3Dclick
> _______________________________________________
> Sisc-users mailing list
> Sis...@li...
> https://lists.sourceforge.net/lists/listinfo/sisc-users

[Jscheme-user] Scheme UK Meeting: 7 December 2005

[Noel W. <noe...@ya...>]

           Scheme UK Meeting: 7 December 2005

The next meeting of the Scheme UK user's group will be held
on 7 December 2005 from 7pm till we leave for the
pub.  The meeting will take place at the offices of LShift
(see http://www.lshift.net/contact.html for directions).
This meeting will be held in conjuction with UK Lispers.

Shriram Krishnamurthi: Verification and Change-Impact
Analysis of Access-Control Policies

Sensitive data are increasingly available on-line through
the Web and other distributed protocols. This heightens the
need to carefully control access to data. Control means not
only preventing the leakage of data but also permitting
access to necessary information. Indeed, the same datum is
often treated differently depending on context.

System designers create policies to express conditions on
the access to data. To reduce source clutter and improve
maintenance, developers increasingly use domain-specific,
declarative languages to express these policies. In turn,
administrators need to analyze policies relative to
properties, and to understand the effect of policy changes
even in the absence of properties.

This talk will discuss Margrave, a software suite for
analyzing role-based access-control policies. Margrave
includes a verifier that analyzes policies written in the
XACML language, translating them into a form of
decision-diagram to answer queries. It also provides
semantic differencing information between versions of
policies. Margrave is, of course, implemented in PLT
Scheme.

(Joint work with Kathi Fisler, Leo A. Meyerovich and
Michael
Carl Tschantz)


=========================================================

Scheme UK is a UK based group of people interested in the
Scheme programming language in particular, and advanced
programming languages in general.  We are interested in
both practical and theoretic aspects.  We meet on the
first Wednesday of each month.  Newcomers are welcome.

For more details see:

  http://schematics.sourceforge.net/scheme-uk/


Email: noelwelsh <at> yahoo <dot> com   noel <at> untyped <dot> com
AIM: noelhwelsh
Blogs: http://monospaced.blogspot.com/  http://www.untyped.com/untyping/


		
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Re: [Jscheme-user] inexact->exact

[Timothy J H. <tjh...@br...>]

On Oct 20, 2005, at 5:28 AM, gk...@su... wrote:
> =EF=BB=BF(inexact->exact 7.4323)
> $1 =3D 7
>
> Is this correct?
In JScheme we have not implemented rational numbers so the only exact=20
numbers we have are integers.
Thus, this is the best we can do for the inexact->exact procedure.

If you want rationals you can import the SISC number system by putting=20=

the sisc.jar file in the classpath
and using
    (load "using/siscnum.scm")
It would be a good idea to extend siscnum.scm to provide the correct=20
definition for inexact->exact and
exact->inexact, but we haven't done that yet.... Indeed we get the=20
following behavior
>
> [Timothy-Hickeys-Computer:clip/clip/smath] tim% java -cp=20
> jscheme.jar:sisc.jar jscheme.REPL
> JScheme 7.1 (8/3/04 10:50 PM) http://jscheme.sourceforge.net
> > (load "using/siscnum.scm")
> #t
> > (q "1/5")
> 1/5
> > (* (q "3/14") (q "7/81"))
> 1/54
> > (inexact->exact 1.1)
> 1
> > (exact->inexact (q "1/3"))
>
> (exact->inexact (q "1/3" ))
>
>   =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
> SchemeException: expected object of type real number, but got: , "1/3"
> > (.getClass (q "1/5"))
> class sisc.data.Quantity
> >

Best,
---Tim---




>
>
> -------------------------------------------------------
> This SF.Net email is sponsored by:
> Power Architecture Resource Center: Free content, downloads,=20
> discussions,
> and more. http://solutions.newsforge.com/ibmarch.tmpl
> _______________________________________________
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> Jsc...@li...
> https://lists.sourceforge.net/lists/listinfo/jscheme-user

[Jscheme-user] inexact->exact

[<gk...@su...>]

=EF=BB=BF(inexact->exact 7.4323)
$1 =3D 7

Is this correct?

[Jscheme-user] jscheme cookbook

[Noel W. <noe...@ya...>]

--- jsc...@li... wrote:

> > Any thoughts?
> Maybe the best approach would be to create a
> jschemecookbook wiki
> (a la wikipedia) with discussion/history pages. I'll look
> into setting  
> up a
> cookbook wiki for jscheme next week. 

You can use the same site that hosts the other Scheme
Cookbook.  There are, for example, a Chicken and Erlang
cookbooks at the same site.

Cheers,
Noel

Email: noelwelsh <at> yahoo <dot> com   noel <at> untyped <dot> com
AIM: noelhwelsh
Blogs: http://monospaced.blogspot.com/  http://www.untyped.com/untyping/

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