[racket] Creating a useful snip

Should I update the docs to mention that as one that must be overridden?

Jay

2011/4/5 Robby Findler <robby at eecs.northwestern.edu>:
> copy.
>
> Robby
>
> On Tue, Apr 5, 2011 at 1:34 PM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:
>> I'm trying to create a useful snip that displays a different sub-snip
>> every second. I think I've overridden every method required to get a
>> "useful" snip, but nothing gets display in DrRacket and the functions
>> aren't called ever. Are there other methods that need to be
>> overridden?
>>
>> The code is below...
>>
>> Jay
>>
>> #lang racket/base
>> (require (for-syntax racket/base)
>>         racket/class
>>         racket/function
>>         racket/runtime-path
>>         racket/snip)
>>
>> (define reactive-snip%
>>  (class* snip% ()
>>    (init-field sub-snips)
>>
>>    (printf "Snips: ~a\n" sub-snips)
>>
>>    (define (the-snip)
>>      (list-ref sub-snips
>>                (modulo (current-seconds) (length sub-snips))))
>>
>>    (define-syntax-rule (delegate id)
>>      (define/override (id . a)
>>        (define some-snip (the-snip))
>>        (printf "Delegating (~a ~a) to ~a\n"
>>                'id a
>>                some-snip)
>>        (send/apply some-snip id a)))
>>
>>    (delegate get-extent)
>>    (delegate draw)
>>    (delegate get-text)
>>    ; set-unmodified or modified
>>
>>    (super-new)))
>>
>> (define-runtime-path img1 '(lib "PLT-206-larval.png" "icons"))
>> (define-runtime-path img2 '(lib "PLT-206-mars.jpg" "icons"))
>>
>> (define sub-snips
>>      (map (curry make-object image-snip%)
>>           (list img1 img2)))
>>
>> (define x
>>  (make-object
>>      reactive-snip%
>>    sub-snips))
>>
>> sub-snips
>>
>> x
>>
>> --
>> Jay McCarthy <jay at cs.byu.edu>
>> Assistant Professor / Brigham Young University
>> http://faculty.cs.byu.edu/~jay
>>
>> "The glory of God is Intelligence" - D&C 93
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>



-- 
Jay McCarthy <jay at cs.byu.edu>
Assistant Professor / Brigham Young University
http://faculty.cs.byu.edu/~jay

"The glory of God is Intelligence" - D&C 93