[Mkcl-devel] Metaclass migration is not an error! Was: [Asdf-devel] Program with metaclass on MKCL.

[Jean-Claude Beaudoin]

On Thu, Dec 4, 2014 at 11:06 PM, Jean-Claude Beaudoin <
jean.claude.beaudoin at gmail.com> wrote:

>
> On Thu, Dec 4, 2014 at 5:20 AM, D. Martinez <denis.martinez at live.com>
> wrote:
>
>> Hello. Being new to "serious" CL programming I am hitting a brick wall
>> right now in one CLOS project.
>> After some time of infructuous searching I cannot find the source of my
>> problem, which may be of either MKCL or ASDF but I lack the knowledge to
>> debug this. Mr. JCB, who I have seen active on this list, may (hopefully!)
>> be able to shed some light on the issue.
>>
>>
> This is definitely a MKCL 1.1.X bug, and one of the "unexpected
> consequence" variety.  ASDF is not concerned by this problem. It may have
> helped in revealing the issue but nothing more, and it played only an
> incidental role in the matter.
>
>
>
I further checked the ANSI CL spec along with the MOP spec and I could not
find any justification in them for signaling an error when migrating a
class from one metaclass to another.

MKCL inherited this error signaling behavior from its original fork away
from ECL and I fail to understand the reason for its existence.

Therefore I simply removed it and adjusted the rest of the surrounding
method accordingly.
This change is now on the MKCL git repo master head.

With this modification your sample code compiles and loads without error,
as is, and without any further adjustment to MKCL.

Cheers,

JCB
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