[Jscheme-user] Re: hack of the day 2 - building debugging tools

[Ken A. <kan...@bb...>]

Yes a snippets page would be good.  I've started collecting the hacks i've sent out as email.  I think they should be examples of real code we've needed to use.  elf/ and using/ are mostly that.  I use them every day.

Developing JScheme idioms is important because it really sets JScheme programming apart from Java programming.  I've been doing a lot of gui development, i don't have the idiom right yet, but its nice to know you can develop a Java gui without writing a class, or compiling anything, and can change the behavior on the fly.

I couldn't tell how the new parameter in the servlet is being used!?

At 08:33 PM 6/24/2004 -0400, Timothy John Hickey wrote:
>Nice example!
>
>Maybe we should create a webpage of Jscheme snippets on the  
>jscheme.sourceforge.net site.
>This one  could be titled something like
>
>   * generate a sort list of selected fields from tab-separated file of  
>records...

And we should say where to get such data.  Geoffrey had the same data i did because we are working on projects related to aviation.

>Here's an example I wrote today.
>Its a servlet that generates a webpage showing all of the symbols that  
>are defined
>
>If you call it with a "which" parameters, e.g.
>      show_bindings.servlet?new
>it will filter out all of the primitives, all of the javadot, and all  
>those symbols defined in elf/basic.scm
>
>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>;;; show_bindings.servlet
>(servlet (new)
>  (define js (jscheme.JScheme.))
>  (define mod (.eval js '(use-module "elf/basic.scm")))
>
>  (define (getBindings env)  (.rep$# env))
>  (define jsenv (.INTERACTION_ENVIRONMENT$ (.evaluator$# js)))
>
>  (define primitives
>     (getBindings jsenv))
>  (define currentbindings
>     (getBindings (.INTERACTION_ENVIRONMENT$  
>(jsint.Scheme.currentEvaluator))))
>
>  (define newbindings
>     (filter
>          (lambda(x)
>              (or (equal? which #null)
>                (and
>                   (equal? #null (.get primitives x))
>                   (= -1 (.indexOf (.toString x) "."))  )))
>         (map* (lambda(x) x) (.keys currentbindings))))
>
>  (define (show-bindings)
>    {<ol>[
>      (map*
>        (lambda(x){<li>[x] </li>\n})
>        (sort newbindings (comparator string<? .toString)))
>         ]
>    </ol>})
>
>(show-bindings)
>)
>;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
>
>
>This is somewhat fragile code however since it uses the jsint package  
>and things may change
>more rapidly in jsint than in jscheme (witness the disappearance of  
>jsint.Version.java!)
>
>---Tim---
>
>On Jun 23, 2004, at 7:10 PM, Ken Anderson wrote:
>
>>I wrote this piece of code today and it struck me:
>>
>>(define (readCountryData)
>>  (sort
>>   (remove-duplicates
>>    (readingTabData
>>     (File. "../dafif/Dafift/AppC/appc_cc_icao.txt")
>>     (lambda (country country_name icao_rgn usage)
>>       (list country country_name))))
>>   (comparator string<? car)))
>>
>>(define (readingTabData file f)
>>  (map* (lambda (r) (apply f (vector->list (.split r "\t"))))
>>        (BufferedReader. (FileReader. file))))
>>
>>Now, this code can be improved in a lot of ways, but it did what i  
>>wanted - grind over a tab separated file, extract the fields i wanted,  
>>and sort the result.  It also abstracted out readinging from a tab  
>>separated file so it can be resused.
>>
>>While you might argue that i should have produced an iterator to be  
>>Java compatible, to do it in Java, you'd need  an interface with  
>>methods call and apply, and each of the 4 loops would require at least  
>>50% more lines of code.
>>
>>
>>
>>-------------------------------------------------------
>>This SF.Net email sponsored by Black Hat Briefings & Training.
>>Attend Black Hat Briefings & Training, Las Vegas July 24-29 -
>>digital self defense, top technical experts, no vendor pitches,
>>unmatched networking opportunities. Visit www.blackhat.com
>>_______________________________________________
>>Jscheme-user mailing list
>>Jsc...@li...
>>https://lists.sourceforge.net/lists/listinfo/jscheme-user