[elephant-devel] changing association slots

[LukasGiessmann]

Hi Ian,

I know this is not the right space to place this question butI don´t know
were else I should do it.
Tried to get an account for http://trac.common-lisp.net/elephant; I wrote
a mail to admin at common-lisp.net but haven´t got an answer yet.
Is there another possibility to mark this bug?

Best regards
Lukas

> I haven't looked at that code in a bit, but I suspect that the right
> thing happens if you just remove the association definition from
> defclass and reevaluate the defclass form.  Can you mark this as a bug
> in elephant so I can remember to look into it later?
>
> Thank you,
> Ian
>
> On Jul 4, 2008, at 4:24 AM, LukasGiessmann wrote:
>
>> hello,
>>
>> since our last mail working with associations turned out to go quite
>> well
>> but one more problem came up:
>> i tried to change the associations by removing it and replacing it
>> by a
>> new association. but the function "remove-association" only works
>> partially.
>>
>> 1. in this one-to-one association the function doesn't work at all.
>> ---
>> (defpclass job()
>>  ((title :initarg :title :accessor title-of :index t)
>>   (company :initarg :company :accessor company-of :index t)
>>   (job-holder :initarg :job-holder :accessor job-holder-of :associate
>> person)))
>>
>> (defpclass person()
>>  ((name :initarg :name :accessor name-of :index t)
>>   (job :initarg :job :accessor job-of :associate job)))
>> ---
>>
>> an error message shows up:
>>
>> (remove-association *job1* 'job-holder *person1*) ; -> There is no
>> applicable method for the generic function  #<STANDARD-GENERIC-
>> FUNCTION
>> ELEPHANT::OID (1)> when called with arguments (NIL).
>>
>> same thing happens when i use the following statement:
>> (setf (job-holder-of *job1*) nil)
>>
>>
>> 2. by one-to-many associations generally nothing happens at all.
>> ---
>> (defpclass job()
>>  ((title :initarg :title :accessor title-of :index t)
>>   (company :initarg :company :accessor company-of :index t)
>>   (job-holders :accessor job-holders-of :associate (person job))))
>>
>> (defpclass person()
>>  ((name :initarg :name :accessor name-of :index t)
>>   (job :initarg :job :accessor job-of :associate job)))
>> ---
>>
>> it only works in this case:
>> ---
>> (drop-instance *person2*)
>> (remove-association *job2* 'job-holders *person2*)
>> ---
>>
>>
>> 3. in the case of many-to-many associations everything goes fine.
>>
>> how do i get the "remove-association" function to work?
>> are there other ways for changing associations?
>>
>>
>> thank you for your help
>>
>> lukas
>>
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>
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