Re: Dynamic-Slot-Value-Using-Slotd?


On 19 Feb 2006, at 21:33, Klaus Harbo wrote:

> I have been looking at getting Elephant, a library for persistent  
> objects, to work with Lispworks.  I've gotten some things to work  
> and am working at getting the persistent classes to behave... I am  
> encountering a problem that I have been unable to figure out: I get  
> the error
>
>    Dynamic-Slot-Value-Using-Slotd is not defined for slot %OID in  
> #<FOO7 250B10EC>
>       [Condition of type SIMPLE-ERROR]
>
>    Restarts:
>      0: [ABORT] Abort handling SLIME request.
>      1: [ABORT] Quit process.
>
>    Backtrace:
>      0: CONDITIONS::CONDITIONS-ERROR (:INVISIBLEP T "Dynamic-Slot- 
> Value-Using-Slotd is not defined for slot ~s in ~s" (%OID #<FOO7  
> 250B10EC>))
>      1: (METHOD (SETF CLOS::DYNAMIC-SLOT-VALUE-USING-SLOTD) (T T  
> T)) (51 #<FOO7 250B10EC> #<PERSISTENT-EFFECTIVE-SLOT-DEFINITION % 
> OID 250A47A4>)
>      Locals:
>        CLOS::NEW-VALUE = 51
>        CLOS::INSTANCE = #<FOO7 250B10EC>
>        CLOS::SLOTD = #<PERSISTENT-EFFECTIVE-SLOT-DEFINITION %OID  
> 250A47A4>
>      [No catch-tags]
>      2: CLOS::CACHE-MISS-FUNCTION (:INVISIBLEP T &REST (51  
> #<PERSISTENT-METACLASS FOO7 206FFF6C> #<FOO7 250B10EC> %OID))
>      3: (METHOD (SETF CLOS::DYNAMIC-SLOT-VALUE-USING-SLOTD) (T T  
> T)) (51 #<FOO7 250B10EC> #<PERSISTENT-EFFECTIVE-SLOT-DEFINITION % 
> OID 250A47A4>)
>      4: (METHOD INITIALIZE-INSTANCE :BEFORE (PERSISTENT)) (#<FOO7  
> 250B10EC> &REST :DONT-KNOW &KEY NIL NIL #<SQL-STORE-CONTROLLER  
> 24EF5154>)
>      5: #<function 208560CA> NIL
>      6: CLOS::CACHE-MISS-FUNCTION (:INVISIBLEP T &REST (#<FOO7  
> 250B10EC> NIL))
>      7: #<function 207E1232> NIL
>
> I believe I have rudimentary understanding of how metaclasses play,  
> but I haven't been able to figure out the cause of this.  I am  
> wondering if anyone on the list might have seen this error, or have  
> an idea as to the cause of it?

The CLOS MOP specification states that the slot-xxx-using-class  
functions are specialized on slot definition metaobjects (among other  
parameters). LispWorks doesn't implement this correctly, but  
specializes on slot names instead.

You may want to consider using the Closer to MOP compatibility in  
which I have fixed this.


Cheers,
Pascal

-- 
Pascal Costanza, mailto:pc@p-cos.net, http://p-cos.net
Vrije Universiteit Brussel, Programming Technology Lab
Pleinlaan 2, B-1050 Brussel, Belgium