[closer-devel] two defun's MIA

[Pascal Costanza]

OK, I have done a few quick checks in the various CLOS  
implementations, and clisp, ecl, MCL and LispWorks have problems with  
one way or the other.

Here is a dirty workaround that should work on all systems, though:

(loop for class in direct-superclasses
       thereis (ignore-errors (subtypep class (find-class 'my-object))))

This should get your code working.

I will add more detailed checks on forward-referenced-class to the  
MOP Feature Tests and then proceed by either submitting bug reports  
and/or trying to fix things in Closer to MOP. This will take a while,  
though.

Cheers,
Pascal

On 1 Nov 2006, at 00:58, Attila Lendvai wrote:

>
> (defmethod initialize-instance :around
>   ((class my-class) &rest initargs
>    &key direct-superclasses)
>   (declare (dynamic-extent initargs))
>   (if (loop for class in direct-superclasses
>             thereis (subtypep class (find-class 'my-object)))
>
> hm, this subtypep check errors on clisp when class is a  forward  
> referenced class.
>
> i could overcome it by (and (class-finalized-p ...)...) but that  
> doesn't feel right. (looking at the clisp backend in closer-mop i  
> couldn't find anything related).
>
> This idiom doesn't work in some CLOS implementations, but when you  
> use Closer to MOP, the respective problems are fixed, so you can  
> use this idiom in all implementations that Closer to MOP supports.
>
> what do you mean by "when you use Closer to MOP"? i looked around  
> in the sources but couldn't find anything related. it's not an  
> important issue, i'm fine with sbcl, but as an opensource lib it's  
> not nice to be tied to implementations.
>
> -- 
> - attila
>
> "- The truth is that I've been too considerate, and so became  
> unintentionally cruel...
> - I understand.
> - No, you don't understand! We don't speak the same language!"
> (Ingmar Bergman - Smultronstället)

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




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