[Moptilities-devel] [PATCH] remove subclassp definition, as it is now part of closer-mop
Gary King
gwking at metabang.com
Fri Nov 7 16:14:46 UTC 2008
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>
> --
> I write stuff at http://failex.blogspot.com/ now. But the post
> formatter and themes are terrible for sharing code, the primary
> content, so it might go away sooner or later.
--
Gary Warren King, metabang.com
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