[plt-scheme] Re: GUI

(require htdp/gui)

(define w 
  (create-window
   (list
    (list
     (make-button "go" 
                  (lambda (e)
                    (begin
                      (hide-window w)
                      (local ((define w 
                                (create-window 
                                 (list (list (make-button "stop" (lambda (e) (hide-window w))))))))
                        true))))))))


On Jan 6, 2010, at 6:18 PM, Avi wrote:

> Please disregard my last few statements, I have decided to change my
> code based on the revisions that matthias gave me, but I have run into
> a new problem, I want to have certain gui windows open other gui
> windows, but they all open at once, also I would like to know how to
> make a function run when certain text is put into a text box.
> -Thanks
> 
> On Jan 6, 3:37 pm, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
>> After fixing numerous syntactic mistakes (in a nonsensical but  
>> grammatically correct way), the two windows pop up just fine:
>> 
>> ;; Intermediate plus Lambda
>> 
>> (require htdp/gui)
>> 
>> (define a-text-choices
>>      (make-message "Please pick what you want to do."))
>> (define options
>>   (list "Compound""Moles(experimental)"))
>> (define choices (make-choice options))
>> 
>> (define b-text-field
>>      (make-text "Please input number of elements"))
>> 
>> (define (choose-prog x)
>>   (cond
>>     [(symbol=? 2 (text-contents b-text-field)) "Molecule2"]
>>     [(symbol=? 3 (text-contents b-text-field)) "Molecule3"]
>>     [(symbol=? 4 (text-contents b-text-field)) "Molecule4"]))
>> 
>> (define Element-Window
>>    (create-window
>>         (list (list b-text-field)
>>               (list (make-button "Go" ; choose-prog
>>                                  (lambda(e) (hide-window Element-
>> Window)))))))
>> 
>> (define (choose x)
>>   (cond
>>     [(symbol=? 0 (choice-index choices))Element-Window]))
>> 
>> (create-window (list (list a-text-choices)(list choices) (list (make-
>> button "OK" choose))))
>> 
>> ;; ---
>> 
>> Since I don't know what you want to achieve, I can't help much more. I  
>> can tell you, though, that you should design individual functions with  
>> check-expect tests and examples and so on.
>> 
>> Good luck -- Matthias
>> 
>> On Jan 5, 2010, at 7:28 PM, Avi wrote:
>> 
>> 
>> 
>>> I have a program which (perhaps I should add that I began scheme 2
>>> months ago) gives me the following error:
>> 
>>> reference to an identifier before its definition: choose-prog <----
>>> This is a definition
>> 
>>> I know how to fix this error, but when I move my GUI file above this
>>> definition, it will give me another error that tells me  that I can
>>> not use a program before I define it. A runs B, but B takes data from
>>> A so B must come after A, but A also must go after B because of the
>>> manner in which the scheme compiler works. Please help me resolve. If
>>> I did not do a good enough job explaining, try it for yourself with
>>> this code (this is the code i'm having trouble with).
>> 
>>> (define a-text-choices
>>>     (make-message "Please pick what you want to do."))
>>> (define options
>>>  (list "Compound""Moles(experimental)"))
>>> (define choices
>>>  (make-choice options)
>>> (define b-text-field
>>>     (make-text "Please input number of elements"))
>> 
>>> (define choose-prog
>>>  (cond
>>>    [(symbol=? 2 (text-contents b-text-field)) Molecule2]
>>>    [(symbol=? 3 (text-contents b-text-field)) Molecule3]
>>>    [(symbol=? 4 (text-contents b-text-field)) Molecule4]))
>> 
>>> (define Element-Window
>>>   (create-window
>>>        (list (list b-text-field)(list (make-button "Go" choose-prog
>>> (lambda(e)(hide-window Element-Window)))))))
>> 
>>> (define choose
>>>  (cond
>>>    [(symbol=? 0 (choice-index choices))Element-Window]))
>> 
>>> (create-window
>>>        (list(list a-text-choices)(list choices)(make-button "OK"
>>> choose)))
>> 
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