[Moptilities-devel] [PATCH] remove subclassp definition, as it is now part of closer-mop

[Gary King]

Hi Stephen,

Thanks for this patch. I just pushed it out.



On Nov 6, 2008, at 10:15 PM, Stephen Compall wrote:

> closer-mop added subclassp as a regular function, as described in this
> log:
>
> Thu Nov  6 06:17:13 CST 2008  pc at p-cos.net
>  * Added utility function subclassp.
>
>  Some CLOS implementations have problems with determining subtype
>  relationships between classes in certain corner cases. For example,
>  clisp doesn't like to determine such relationships for forward
>  referenced classes, and some instances of PCL have problems with
>  anonymous classes under certain circumstances (primarily when doing
>  CLOS MOP programming).
>
>  Apparently, subtypep is typically implemented based on the class
>  precedence list, which can only be determined until after a class has
>  been finalized, and this seems to be one of the reasons for these
>  problems. However, the CLOS MOP places restrictions on methods for
>  compute-class-precedence-list such that the subtype relationship
>  actually does _not_ depend on the precedence list, but can be based  
> on
>  a membership test in the unordered set of all direct and indirect
>  superclasses.
>
>  I have provided subclassp in Closer to MOP as a utility function that
>  does just that: It walks the superclass hierarchy to determine  
> whether
>  one class is a subclass of another. This implementation is not that
>  efficient, so it should only be used when subtypep fails. (It could
>  probably be made more efficient, but since this is only provided as a
>  replacement for subtypep in hopefully rare corner cases, I haven't  
> put
>  the energy into this to do this yet.)
>
> The attached patch removes the Moptilities subclassp definitions, so  
> it
> just reexports closer-mop's version.
>
> <moptilities.remove-subclassp-gf.dpatch>
> -- 
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> formatter and themes are terrible for sharing code, the primary
> content, so it might go away sooner or later.

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