[racket] formlets with radio button & checkbox example?

The 'n' argument to the lambda is the number of form elements so far,
and make-input* allocates another one, so this thing's name should be
(format "input_~a" n) or something like that.

Jay

On Thu, Dec 29, 2011 at 12:59 AM, Shad Gregory <captshadg at austin.rr.com> wrote:
> Sigrid,
>
> Here's something that worked for me:
>
> (define (radio-group values name)
>  (make-input*
>   (lambda (n)
>     `(div
>       ,@(for/list ((value values))
>           (list 'div
>                 (list 'input
>                       (list
>                        (list 'name name)
>                        (list 'type "radio")
>                        (list 'value (bytes->string/utf-8 value))))
>                 (bytes->string/utf-8 value)))))))
>
>
> (define radio-button-formlet
>  (formlet
>   (div
>        ,{(default #"default" (radio-group (list #"Chocolate" #"Vanilla"
> #"Strawberry") "flavor")) . => . ci} )
>   (list ci)))
>
> Hope this helps,
>
> Shad
>
>
> On 12/27/2011 3:20 PM, keydana at gmx.de wrote:
>
>> Jay,
>>
>> many thanks for the answer, that already helps a lot!
>>
>> Just one thing - the generated html does not have a "value" attribute, but
>> instead uses a different "name" for every radio button - how can I get the
>> radio buttons identified as a group by the browser, such that only one
>> button can be selected?
>>
>> In fact, looking at the generated html as well as the input given to
>> formlet-process, I do not see where the "value" passed to the radio
>> constructor is used?
>>
>> Thanks again,
>> Sigrid
>>
>>
>>
>>
>>
>> Am 26.12.2011 um 22:28 schrieb Jay McCarthy:
>>
>>> Here is a short example:
>>>
>>> #lang racket
>>> (require racket/promise
>>>         web-server/http/request-structs
>>>         web-server/formlets
>>>         net/url)
>>>
>>> (define some-formlet
>>>  (formlet
>>>   (div "Checked Radio"
>>>        ,{(default #"default" (radio #"checked-radio" #t)) . =>  . cr}
>>>        "Not-Checked Radio"
>>>        ,{(default #"default" (radio #"unchecked-radio" #f)) . =>  . ncr}
>>>        "Checked Checkbox"
>>>        ,{(default #"default" (checkbox #"checked-checkbox" #t)) . =>  .
>>> cc}
>>>        "Not-Checked Checkbox"
>>>        ,{(default #"default" (checkbox #"uncheck-checkbox" #f)) . =>  .
>>> ncc})
>>>   (list cr ncr cc ncc)))
>>>
>>> (formlet-display some-formlet)
>>>
>>> (define (show-example bs)
>>>  (formlet-process some-formlet
>>>                   (request #"GET"
>>>                            (string->url "http://localhost")
>>>                            empty
>>>                            (delay bs)
>>>                            #f
>>>                            "host"
>>>                            8943
>>>                            "client")))
>>>
>>> (show-example empty)
>>> (show-example (list (binding:form #"input_0" #"true")))
>>> (show-example (list (binding:form #"input_0" #"true")
>>>                    (binding:form #"input_1" #"false")))
>>> (show-example (list (binding:form #"input_0" #"true")
>>>                    (binding:form #"input_1" #"false")
>>>                    (binding:form #"input_2" #"true")
>>>                    (binding:form #"input_3" #"false")))
>>>
>>> It would be good to create a higher-level formlet that rendered to a
>>> checkbox or radio button that would return a boolean or a selection,
>>> like the select formlets do.
>>>
>>> Jay
>>>
>>> On Mon, Dec 26, 2011 at 12:02 PM, keydana at gmx.de<keydana at gmx.de>  wrote:
>>>>
>>>> Hi,
>>>>
>>>> it's me again, and whereas I don't know how dumb I am I sure might have
>>>> been a bit lazy :-;
>>>>
>>>> Unfortunately, even after taking a bit more time, I don't know how it
>>>> works. Lastly, I've been trying this, which displayed fine:
>>>>
>>>> (define f-choose-db
>>>>  (let ((o (radio #"orcl" #t))
>>>>        (r (radio #"rndba" #f)))
>>>>    (formlet
>>>>     (div "orcl" ,(o . =>  . orcl)
>>>>          "rndba" ,(r . =>  . rndba))
>>>>     (values orcl rndba))))
>>>>
>>>> But when I use formlet-process to extract the result (just clicking
>>>> submit, leaving the checked box checked), I get the values #<binding:form>
>>>>  and #f... (and see input_0=on in the browser).
>>>>
>>>> Also I was trying to add a binding name to the radio function calls
>>>> themselves, e.g. (radio #"xx" #f . =>  . myname), but this throws a syntax
>>>> error.
>>>>
>>>> Could anyone offer a hint what I'm doing wrong here?
>>>>
>>>> (BTW this list has the most helpful people&  inspiring content of all
>>>> mailing lists I know of , and I'm not writing this in order to get a nice
>>>> answer :-) )
>>>>
>>>>
>>>> Ciao
>>>> Sigrid
>>>>
>>>>
>>>> ____________________
>>>>  Racket Users list:
>>>>  http://lists.racket-lang.org/users
>>>
>>>
>>>
>>> --
>>> 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
>>
>>
>> ____________________
>>   Racket Users list:
>>   http://lists.racket-lang.org/users
>>
>



-- 
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