[CM] OSX - OpenMCL .14, build from CVS w/ CLM

[Rick Taube]

thank you so much! im finalizing the sotware for the cd release this 
week and ill try to include this as well.

On Saturday, Nov 29, 2003, at 23:58 America/Chicago, Robert Sayre wrote:

> I've gotten CM to build (and work!) on OpenMCL .14... but I did it
> incorrectly. Below, there is a response to my questions about 
> OpenMCL's MOP
> from Gary Byers. I made a similar mistake (which Byers corrects) in
> FINALIZE-CLASS when I built CM.
>
>> From the last email I sent about this issue:
>
> ? (load "/Users/myuser/music/cm/src/cm.lisp")
> ; Loading "/Users/myuser/music/cm/bin/pkg.dfsl".
> ; Loading "/Users/myuser/music/cm/bin/openmcl.dfsl".
>
> ...
>
> ; Compiling "/Users/myuser/music/cm/src/sco.lisp".
> ; Loading "/Users/myuser/music/cm/bin/sco.dfsl".
>> Error in process listener(1):
>>   The class #<STANDARD-CLASS EVENT-STREAM> was specified as: a
>>   super-class of the class #<IO-CLASS SCO-STREAM>;
>>   but the meta-classes #<STANDARD-CLASS STANDARD-CLASS> and
>>   #<STANDARD-CLASS IO-CLASS> are incompatible.
>> While executing: #<CCL::STANDARD-KERNEL-METHOD SHARED-INITIALIZE 
>> :AFTER
> (CCL::STD-CLASS T)>
>
> The reply I got from GB indicates that it will be difficult to take 
> care of
> the problem by specializing the FINALIZE-CLASS function for OpenMCL. 
> Would
> it be possible to declare VALIDATE-SUPERCLASSES methods inline, or 
> would
> that break other implementations?
>
> Robert Sayre
>
>
> ------ Forwarded Message
> From: Gary Byers <gb at clozure.com>
> Date: Sat, 29 Nov 2003 21:57:13 -0700 (MST)
> To: Robert Sayre <mint at franklinmint.fm>
> Cc: openmcl-devel at clozure.com
> Subject: Re: [Openmcl-devel] MOP question
>
>
> On Sat, 29 Nov 2003, Robert Sayre wrote:
>
>> I have some questions about the MOP in OpenMCL .14 and also about a 
>> compiler
>> warning. The following example is taken from an old comp.lang.lisp 
>> thread
>> titled "MOP/pcl anomaly in CMUCL?"*
>>
>>
>> Welcome to OpenMCL Version (Alpha: Darwin) 0.14-031108!
>> ? (defclass dynamic-slots-class (standard-class) ())
>> #<STANDARD-CLASS DYNAMIC-SLOTS-CLASS>
>> ?  (defclass test () ((a1)) (:metaclass dynamic-slots-class))
>>> Error in process listener(1): The class #<STANDARD-CLASS 
>>> STANDARD-OBJECT>
> was
>>> specified as a
>>> super-class of the class #<DYNAMIC-SLOTS-CLASS TEST>;
>>> but the meta-classes #<STANDARD-CLASS STANDARD-CLASS> and
>>> #<STANDARD-CLASS DYNAMIC-SLOTS-CLASS> are incompatible.
>>> While executing: #<CCL::STANDARD-KERNEL-METHOD SHARED-INITIALIZE 
>>> :AFTER
>> (CCL::SLOTS-CLASS T)>
>>> Type :POP to abort.
>>
>>
>> From the usenet thread, I learned that
>>
>> "It's neccessary to define methods on pcl:validate-superclass more 
>> often
>> than is mentioned in AMOP.
>>
>> [This] issue will probably lie at the heart of your problem:  Since
>> test (whose metaclass is dynamic-slots-class) inherits from t (whose
>> metaclass is standard-class), you have to define this combination
>> valid"
>>
>
> I guess that I could agree that since (a) the default method for
> VALIDATE-SUPERCLASS only returns T for a few classes that it knows
> about and conservatively returns NIL for those clasees that it doesn't
> know about and (b) it's often then case that certain subclass
> relationships could exist between a user-defined metaclass and some
> other class, it's often necessary to explicitly define specialized
> VALIDATE-SUPERCLASS methods.
>
>
>> So, I followed this advice and it worked:
>>
>>
>> ? (defmethod openmcl-mop:validate-superclass
>>     ((class dynamic-slots-class) (super ccl::standard-class))
>>   t)
>> #<STANDARD-METHOD VALIDATE-SUPERCLASS (DYNAMIC-SLOTS-CLASS 
>> STANDARD-CLASS)>
>> ? (defclass test () ((a1)) (:metaclass dynamic-slots-class))
>> #<DYNAMIC-SLOTS-CLASS TEST>
>>
>>
>> This problem arose while trying to build Common Music for OpenMCL .14.
>> Common Music runs on a number of implementations, including OpenMCL 
>> .13.7
>> and MCL. It appears that neither of them require the combination to be
>> declared valid. Is this divergence intentional?
>
> The MOP spec is online at <http://www.lisp.org/mop/index.html>.  I
> think that the rationale for requiring that VALIDATE-SUPERCLASS be
> called when it is that the question of whether a superclass
> relationship can meaningfully exist between two class objects is best
> determined by the implementor of those classes, and the implementor
> is therefore requuired to define VALIDATE-SUPERCLASS methods to decide
> that question.
>
> Neither MCL nor OpenMCL 0.13 make much of an attempt to adhere to the
> MOP and OpenMCL 0.14 does, so in that sense the divergence is
> intentional.
>
>
>>
>> Also, CM uses a function called "finalize-class" that varies based on
>> implementation. I assume it's there for just this sort of situation. 
>> When I
>> define it the following way, I get a compiler warning, but it seems 
>> to work.
>> If I uncomment the print statement, there is no warning. In the 
>> following
>> example, why doesn't the use of "the-class" in defmethod count as a 
>> use of
>> the variable?
>>
>> ? (defun finalize-class (the-class)
>>   (progn
>>     ;(print the-class)
>>     (defmethod openmcl-mop:validate-superclass
>>         ((the-class class) (super ccl::standard-class))
>>             t)))
>> ;Compiler warnings :
>> ;   Unused lexical variable THE-CLASS, in FINALIZE-CLASS.
>> FINALIZE-CLASS
>> ? (defclass dynamic-slots-class (standard-class) ())
>> #<STANDARD-CLASS DYNAMIC-SLOTS-CLASS>
>> ? (finalize-class 'dynamic-slots-class)
>> #<STANDARD-METHOD VALIDATE-SUPERCLASS (CLASS STANDARD-CLASS)>
>> ? (defclass test () ((a1)) (:metaclass dynamic-slots-class))
>> #<DYNAMIC-SLOTS-CLASS TEST>
>>
>
> You've (incidentally) defined a method that says that all objects of
> class CLASS can have an object of class STANDARD-CLASS as a
> superclass; after defining that method, your test case should work,
> but probably not for the reason you'd intended (the first specializer
> form in your DEFMETHOD seems to have its subforms backwards.)
>
> If you flipped them around, you'd probably get a complaint that
> there's no class named THE-CLASS: DEFMETHOD's a macro and it doesn't
> evaluate class names used in its argument subforms.  (The fact that
> one of those unevaluated class names happens to match an otherwise
> unused variable name in the surrounding function's just a
> coincidence.)
>
> It's not clear to me that you really want or need to define
> a VALIDATE-SUPERCLASSES method procedurally.  (It's also clear that
> it's awkward and complicated to do so: macroexpand a DEFMETHOD form,
> and ask yourself how often you really want or need to do this ...)
> Admittedly, there may be cases where it's necessary to define methods
> procedurally and it should be at leest a little esaier than it is to
> do so.
>
> In this case, it seems a lot easier to just define the method(s)
> "declaratively":
>
> (defclass dynamic-slots-class () ...)
>
> (defmethod openmcl-mop:validate-superclass ((class dynamic-slots-class)
>                                             (super standard-class))
>   t)
>
>
> ------ End of Forwarded Message
>
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