[racket] Calling Private Methods on non-this Objects?

OH, I'm sorry. Then Matthias was right: you want define-local-member-name.

Robby

On Thursday, May 30, 2013, Sean Kanaley wrote:

> Yes but that only works for "this".  It's basically (send this method args
> ...) == (method args ...).  I wish to call the method on a *different*object of the same class.  C++/Java/C# etc. all allow access to private
> data in "sibling" objects.
>
>
> On Thu, May 30, 2013 at 7:09 PM, Robby Findler <
> robby at eecs.northwestern.edu <javascript:_e({}, 'cvml',
> 'robby at eecs.northwestern.edu');>> wrote:
>
>> When you are inside a class, you don't use send. You just call the method
>> with a regular function-application looking syntax.
>>
>> #lang racket
>> (define c%
>>   (class object%
>>     (define/public (m x)
>>       (printf "n on ~s is ~s\n" x (n x)))
>>     (define/private (n x)
>>       (* x x))
>>     (super-new)))
>>
>> (send (new c%) m 11)
>>
>>
>> Robby
>>
>>
>> On Thursday, May 30, 2013, Sean Kanaley wrote:
>>
>>> In C++ for example, the following is valid:
>>>
>>> class A {
>>> private:
>>>     int test(A a) { return n + a.n; }
>>>     int n;
>>> };
>>>
>>> The key point is the "a.n" is valid.
>>>
>>> I'm trying to create a 3d game in Racket, and in order to avoid
>>> recomputing world transforms all the time, child objects (say a rotatable
>>> gun on a parent tank) take a parameter to their parent which is used to add
>>> the child ("this") to the parent, in order that the parent update a delayed
>>> world transform computation in case of multiple calls to set-trans!,
>>> roughly:
>>>
>>> (define obj%
>>>   (class object% (super-new) (init ... [parent #f])
>>>     (define p parent)
>>>     (define cs '())
>>>     (when p (send p add-child! this))
>>>     (define/public (set-trans! new-t)
>>>       ... <includes delayed world-trans calc>
>>>       (for ([c cs])
>>>         (send c set-trans! (send c local-trans))))
>>>     ...
>>>     (define/public/private/etc. (add-child! c) (set! cs (cons c cs)))))
>>>
>>> It obviously works with "define/public", but I'm hoping there is a way
>>> to not expose the method everywhere.  It's in essence private, but Racket
>>> seems to not allow access even from within the class (send complains "no
>>> such method").
>>>
>>
>
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