[closer-devel] Closer-mop support for ABCL

[Pascal Costanza]

On 26 Aug 2012, at 21:26, Rudolf Schlatte <rudi at constantly.at> wrote:

> 
> On Aug 26, 2012, at 19:17, Pascal Costanza <pc at p-cos.net> wrote:
> 
>> OK, class redefinition doesn't trigger the obsolete instance structure protocol correctly, it seems. Here is a transcript:
>> 
>> CL-USER(1): (defclass person () (name))
>> #<STANDARD-CLASS PERSON {1E631646}>
>> CL-USER(2): (defparameter *p* (make-instance 'person))
>> *P*
>> CL-USER(3): (setf (slot-value *p* 'name) "name")
>> "name"
>> CL-USER(4): (defclass person () (name address))
>> #<STANDARD-CLASS PERSON {1E631646}>
>> CL-USER(5): (use-package :mop)
>> T
>> CL-USER(6): (class-slots (find-class 'person))
>> (#<SYSTEM:SLOT-DEFINITION NAME {1A60232C}> #<SYSTEM:SLOT-DEFINITION ADDRESS {37A0B39B}>)
>> CL-USER(7): (setf (slot-value-using-class (find-class 'person) *p* (second *)) "address")
>> #<THREAD "interpreter" {43F31EDC}>: Debugger invoked on condition of type TYPE-ERROR
>> The value 1 is not of type (INTEGER 0 1).
>> Restarts:
>> 0: TOP-LEVEL Return to top level.
>> 
>> The problematic part seems to be the use of slot-value-using-class here. With just slot-value, this works fine...
> 
> (set-)standard-instance-access didn't check for invalid object layout, fixed in r14137.  Pure slot-value goes through a different code path for classes with metaclass standard-class, which did the check and update already.


Perfect, these bug fixes come in very fast… :)

OK, on to the next bug: It seems that anonymous classes are always considered subtypes of other classes. This is not correct. Here is transcript:

CL-USER(1): (defparameter *c1* (make-instance 'standard-class))
*C1*
CL-USER(2): (defparameter *c2* (make-instance 'standard-class))
*C2*
CL-USER(3): (subtypep *c1* *c2*)
T
T
CL-USER(4): (defclass c1 () ())
#<STANDARD-CLASS C1 {4ABAD094}>
CL-USER(5): (defclass c2 () ())
#<STANDARD-CLASS C2 {2EC195E3}>
CL-USER(6): (subtypep 'c1 'c2)
NIL
T
CL-USER(7): (subtypep (find-class 'c1) (find-class 'c2))
NIL
T
CL-USER(8): (subtypep *c1* 'c1)
T
T
CL-USER(9): (subtypep 'c1 *c1*)
NIL
T

(The integration of types and classes is a bit complex. See 4.3.1 in the HyperSpec, especially the notion of "proper name", and 4.3.7.)

Pascal

--
Pascal Costanza
The views expressed in this email are my own, and not those of my employer.