2009/9/25 Julian Fitzell <jfitzell at gmail.com>:
> Not if you want portability... :)
>
> I was just struggling with this issue yesterday while porting Magritte
> to VAST, actually... I'm thinking of adding ProtoObject-like class to
> the compatibility layer that would need to have appropriate primitive
> methods added by each platform. And I think it will need to subclass
> nil...
>

Another thing about it, that MC package browser (if you click browse
the package without loading it) prints the class definition
incorrectly:

nil subclass: #BBBNameOfSubclass
	instanceVariableNames: ''
	classVariableNames: ''
	poolDictionaries: ''
	category: 'NILSuperClass'


the problem is, that you can't evaluate it, because you'll get DNU.

While system browser prints class definition using 2 statements for a
class which having nil as superclass:

ProtoObject subclass: #BBBNameOfSubclass
       instanceVariableNames: ''
       classVariableNames: ''
       poolDictionaries: ''
       category: 'NILSuperClass'.
BBBNameOfSubclass superclass: nil

Another little concern of mine, is that #superclass: implementation is
very dangerous one:

----------
superclass: aClass
	"Change the receiver's superclass to be aClass."
	"Note: Do not use 'aClass isKindOf: Behavior' here
		in case we recompile from Behavior itself."
	(aClass == nil or: [aClass isBehavior])
		ifTrue: [superclass := aClass.
				Object flushCache]
		ifFalse: [self error: 'superclass must be a class-describing object']
----------

Suppose i got class A with 2 ivars, then i subclass it with class B
and add some other ivars, and then send

B superclass: nil.

At this point, it really should recompile everything. But as you can
see, there is no such check, and i fear to predict what could happen
if you start using instances of such class.

> Julian
>



-- 
Best regards,
Igor Stasenko AKA sig.