Eliot Miranda uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-eem.948.mcz

==================== Summary ====================

Name: Kernel-eem.948
Author: eem
Time: 25 August 2015, 4:45:37.484 pm
UUID: 45d1146b-9349-4519-9108-af1e414c58dc
Ancestors: Kernel-eem.947

Implement Ephemeron class creation, e.g.
Association ephemeronSubclass: #Ephemeron
	instanceVariableNames: ''
	classVariableNames: ''
	poolDictionaries: ''
	category: 'Collections-Weak'

=============== Diff against Kernel-eem.947 ===============

Item was added:
+ ----- Method: Class>>ephemeronSubclass:instanceVariableNames:classVariableNames:poolDictionaries:category: (in category 'subclass creation') -----
+ ephemeronSubclass: t instanceVariableNames: f classVariableNames: d poolDictionaries: s category: cat 
+ 	"This is the standard initialization message for creating a new class as a 
+ 	subclass of an existing class (the receiver) in which the subclass is to 
+ 	have ephemeron semantics, i.e. where the object will be queued for
+ 	finalization when the key (first) inst var is not reachable other than through
+ 	the other fields of ephemerons with unreachable keys."
+ 	^ClassBuilder new
+ 		superclass: self
+ 		ephemeronSubclass: t
+ 		instanceVariableNames: f
+ 		classVariableNames: d
+ 		poolDictionaries: s
+ 		category: cat!

Item was added:
+ ----- Method: ClassBuilder>>superclass:ephemeronSubclass:instanceVariableNames:classVariableNames:poolDictionaries:category: (in category 'public') -----
+ superclass: aClass
+ 	ephemeronSubclass: t instanceVariableNames: f 
+ 	classVariableNames: d poolDictionaries: s category: cat
+ 	"This is the standard initialization message for creating a new class as a 
+ 	subclass of an existing class (the receiver) in which the subclass is to 
+ 	have ephemeron semantics, i.e. where the object will be queued for
+ 	finalization when the key (first) inst var is not reachable other than through
+ 	the other fields of ephemerons with unreachable keys."
+ 	| env |
+ 	aClass isPointers ifFalse:
+ 		[^self error: 'cannot make a pointer subclass of a class with non-pointer fields'].
+ 	aClass instSize + (f subStrings: ' 	\' withCRs) size < 2 ifTrue:
+ 		[^self error: 'cannot make an ephemeron class with less than two named instance varaibles'].
+ 	env := CurrentEnvironment signal ifNil: [aClass environment].
+ 	^self 
+ 		name: t
+ 		inEnvironment: env
+ 		subclassOf: aClass
+ 		type: #ephemeron
+ 		instanceVariableNames: f
+ 		classVariableNames: d
+ 		poolDictionaries: s
+ 		category: cat!