((( [logo]Racket )))Need Help?
AboutDownloadDocumentationPLaneTCommunityLearning

[plt-scheme] Re: GUI

From: Matthias Felleisen (matthias at ccs.neu.edu)
Date: Sun Jan 10 15:20:57 EST 2010		 
Just delete the #t part. 


On Jan 10, 2010, at 9:23 AM, Avi wrote:

> It wont work for me, I get the error
> 
> define: expected only one expression for the function body, but found
> one extra part
> 
> the #t is highlighted when I get this error, since I have only been
> programming for about two or three months I actually do not
> understand
> this part:
> (define (callback x)
>  (cond
>    [(string=? "hello" (text-contents a-text))
>     (display "Hello!\n")]
> 
>    [else
>     (display "No hello?\n")] )
>  #t)
> 
> On Jan 10, 2:30 am, Jon Stenerson <jonstener... at comcast.net> wrote:
>> How about this
>> 
>> #lang scheme
>> (require htdp/gui)
>> 
>> (define a-text
>>      (make-text "Please input number of elements"))
>> 
>> (define (callback x)
>>   (cond
>>     [(string=? "hello" (text-contents a-text))
>>      (display "Hello!\n")]
>> 
>>     [else
>>      (display "No hello?\n")] )
>>   #t)
>> 
>> (define initial-window
>>   (create-window
>>    (list (list a-text)
>>          (list (make-button "GO" callback)) ) ) )
>> 
>> 
>> 
>> On Fri, 2010-01-08 at 12:03 -0800, Avi wrote:
>>> So, I tried to do this, but it did not work for me. Here is what my
>>> sample so far.
>> 
>>> (define a-text
>>>      (make-text "Please input number of elements"))
>> 
>>> (define (test x)
>>>   (cond
>>>     [(string=? "hello" x)(+ 1 1)]))
>> 
>>> (define initial-window
>>>   (create-window
>>>    (list (list a-text)(list (make-button "GO" test )))))
>> 
>>> (define x (text-contents a-text))
>> 
>>> On Jan 8, 9:07 am, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
>>>> (string=? "hello" x) where x is the value from the text field
>> 
>>>> On Jan 7, 2010, at 2:14 PM, Avi wrote:
>> 
>>>>> Could you give me a hint? I was using text-contents a-text-field to
>>>>> use the products of a text field to work. What does text-contents
>>>>> produce?
>> 
>>>>> On Jan 7, 1:47 pm, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
>>>>>> On Jan 7, 2010, at 1:42 PM, Avi wrote:
>> 
>>>>>>> Is there a way to compare what is entered into a text-field using a
>>>>>>> conditional?
>> 
>>>>>> Of course.
>> 
>>>>>>> if x is equal to what is in text box a than run program b
>> 
>>>>>> Yeap.
>> 
>>>>>>> On Jan 6, 10:22 pm, Matthias Felleisen <matth... at ccs.neu.edu> wrote:
>>>>>>>> (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)))
>> 
>>>>>>>>>>> _________________________________________________
>>>>>>>>>>>  For list-related administrative tasks:
>>>>>>>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>> 
>>>>>>>>>> _________________________________________________
>>>>>>>>>>   For list-related administrative tasks:
>>>>>>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>>>>>>>> _________________________________________________
>>>>>>>>>  For list-related administrative tasks:
>>>>>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>> 
>>>>>>>> _________________________________________________
>>>>>>>>   For list-related administrative tasks:
>>>>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>> 
>>>>>> _________________________________________________
>>>>>>   For list-related administrative tasks:
>>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>>>> _________________________________________________
>>>>>  For list-related administrative tasks:
>>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>> 
>>>> _________________________________________________
>>>>   For list-related administrative tasks:
>>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>>> _________________________________________________
>>>   For list-related administrative tasks:
>>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
>> 
>> _________________________________________________
>>   For list-related administrative tasks:
>>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
> _________________________________________________
>  For list-related administrative tasks:
>  http://list.cs.brown.edu/mailman/listinfo/plt-scheme
Posted on the users mailing list.