diff --git a/repository/Fuel-Core-Tests.package/FLBasicSerializationTest.class/instance/testExecuteAfterMaterialization.st b/repository/Fuel-Core-Tests.package/FLBasicSerializationTest.class/instance/testExecuteAfterMaterialization.st
index a615a9c..25ce5ed 100644
--- a/repository/Fuel-Core-Tests.package/FLBasicSerializationTest.class/instance/testExecuteAfterMaterialization.st
+++ b/repository/Fuel-Core-Tests.package/FLBasicSerializationTest.class/instance/testExecuteAfterMaterialization.st
@@ -2,7 +2,7 @@ tests-fuelAfterMaterialization
 testExecuteAfterMaterialization
 
 	| anObject result aClass |
-	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'a' ].
+	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(a) ].
 	self classFactory silentlyCompile: 'fuelAfterMaterialization a := #A' in: aClass.
 	anObject := aClass new.
 
diff --git a/repository/Fuel-Core-Tests.package/FLBlockClosureSerializationTest.class/instance/testBlockClosureMaterializesClassVariablesCorrectly.st b/repository/Fuel-Core-Tests.package/FLBlockClosureSerializationTest.class/instance/testBlockClosureMaterializesClassVariablesCorrectly.st
index 9e1cd49..d26ca72 100644
--- a/repository/Fuel-Core-Tests.package/FLBlockClosureSerializationTest.class/instance/testBlockClosureMaterializesClassVariablesCorrectly.st
+++ b/repository/Fuel-Core-Tests.package/FLBlockClosureSerializationTest.class/instance/testBlockClosureMaterializesClassVariablesCorrectly.st
@@ -2,7 +2,7 @@ tests-change
 testBlockClosureMaterializesClassVariablesCorrectly
 
 	| class closure method |
-	class := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'ClassVariableForTesting' ].
+	class := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(ClassVariableForTesting)].
 	self classFactory silentlyCompile: 'methodWithClosure  ^ [ ClassVariableForTesting ]' in: class.
 
 	method := class methodNamed: #methodWithClosure.
diff --git a/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariable.st b/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariable.st
index a2de20c..c33a81f 100644
--- a/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariable.st
+++ b/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariable.st
@@ -2,11 +2,11 @@ tests
 testMethodAccessingAClassVariable
 
 	| aClassWithVariable aMethod materializedMethod |
-	aClassWithVariable := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'A' ].
+	aClassWithVariable := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(A) ].
 
 	self classFactory silentlyCompile: 'm1 A:= 3' in: aClassWithVariable.
 	aMethod := aClassWithVariable >> #m1.
-	aClassWithVariable classVarNamed: #A put: 7.
+	aClassWithVariable writeClassVariableNamed: #A value: 7.
 
 	materializedMethod := self resultOfSerializeAndMaterialize: aMethod.
 
diff --git a/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariableInADoit.st b/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariableInADoit.st
index 4253779..7171f78 100644
--- a/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariableInADoit.st
+++ b/repository/Fuel-Core-Tests.package/FLCompiledMethodSerializationTest.class/instance/testMethodAccessingAClassVariableInADoit.st
@@ -2,11 +2,11 @@ tests
 testMethodAccessingAClassVariableInADoit
 
 	| aClassWithVariable aMethod materializedMethod |
-	aClassWithVariable := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'A' ].
+	aClassWithVariable := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(A)].
 
 	self classFactory silentlyCompile: 'DoIt A:= 3' in: aClassWithVariable.
 	aMethod := aClassWithVariable >> #DoIt.
-	aClassWithVariable classVarNamed: #A put: 7.
+	aClassWithVariable writeClassVariableNamed: #A value: 7.
 
 	materializedMethod := self resultOfSerializeAndMaterialize: aMethod.
 
diff --git a/repository/Fuel-Core-Tests.package/FLConfigurationTest.class/instance/testStreamFinalizerDefault.st b/repository/Fuel-Core-Tests.package/FLConfigurationTest.class/instance/testStreamFinalizerDefault.st
index 9e2ecfa..1c0f429 100644
--- a/repository/Fuel-Core-Tests.package/FLConfigurationTest.class/instance/testStreamFinalizerDefault.st
+++ b/repository/Fuel-Core-Tests.package/FLConfigurationTest.class/instance/testStreamFinalizerDefault.st
@@ -3,7 +3,7 @@ testStreamFinalizerDefault
 
 	<ignoreNotImplementedSelectors: #( _log )>
 	| logClass log |
-	logClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'log' ].
+	logClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(log) ].
 	self classFactory
 		silentlyCompile: 'initialize log := OrderedCollection new' in: logClass;
 		silentlyCompile: '_log ^ log' in: logClass;
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithClassVariable.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithClassVariable.st
index 27c1e0f..2d49ab9 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithClassVariable.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithClassVariable.st
@@ -3,7 +3,7 @@ testCreateClassWithClassVariable
 	"Tests materialization a class not defined in the image, with a class variable."
 
 	| aClass materializedClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariablesFromString: #ClassVariable ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariables: #(ClassVariable) ].
 	(aClass classVariableNamed: #ClassVariable) write: #test.
 
 	materializedClass := self resultOfSerializeRemoveAndMaterialize: aClass.
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
index 0c96d6f..ebdfe82 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
@@ -5,13 +5,13 @@ testCreateClassWithCreatedTraitWithInstanceVariable
 	The trait has instance variables."
 
 	| aClass aTrait result materializedClass materializedTrait materializedObject |
-	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'ivar' ].
+	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(ivar) ].
 	self classFactory silentlyCompile: 'ivar: x ivar := x' in: aClass.
 	self classFactory silentlyCompile: 'ivar ^ ivar' in: aClass.
 	aTrait := self classFactory silentlyMake: [ :aBuilder |
 		          aBuilder
 			          beTrait;
-			          slotsFromString: 'traitIvar' ].
+			          slots: #(traitIvar) ].
 	self classFactory silentlyCompile: 'traitIvar: x traitIvar := x' in: aTrait.
 	self classFactory silentlyCompile: 'traitIvar ^ traitIvar' in: aTrait.
 	aClass addToComposition: aTrait.
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithInstance.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithInstance.st
index 923dbaf..66b98e1 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithInstance.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithInstance.st
@@ -3,7 +3,7 @@ testCreateClassWithInstance
 	"Tests materialization of a class who references an instance of itself."
 
 	| aClass anInstance materializedClass materializedInstance |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'name' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(name) ].
 	aClass class instanceVariableNames: 'instance'.
 
 	anInstance := aClass new
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithVariables.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithVariables.st
index f23f63e..b0901cc 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithVariables.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateClassWithVariables.st
@@ -3,7 +3,7 @@ testCreateClassWithVariables
 	"Tests materialization of a class not defined in the image, with instance variables."
 
 	| aClass materializedClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'var1 var2' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(var1 var2) ].
 
 	materializedClass := self resultOfSerializeRemoveAndMaterialize: aClass.
 
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateWithClassVariableAccessors.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateWithClassVariableAccessors.st
index 6a32ddc..3ddd6c0 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateWithClassVariableAccessors.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testCreateWithClassVariableAccessors.st
@@ -3,7 +3,7 @@ testCreateWithClassVariableAccessors
 	"Tests materialization of a compiled method in a class not defined in the image. The class defines accessors for a class variable."
 
 	| aClass materializedClass instance |
-	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'AnFLClassVariable' ].
+	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(AnFLClassVariable) ].
 	self classFactory
 		silentlyCompile: 'classVariable ^AnFLClassVariable' in: aClass;
 		silentlyCompile: 'classVariable: value AnFLClassVariable := value' in: aClass.
diff --git a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testMaterializationDoesNotModifySerializedClass.st b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testMaterializationDoesNotModifySerializedClass.st
index 9606a2d..e0fd6e9 100644
--- a/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testMaterializationDoesNotModifySerializedClass.st
+++ b/repository/Fuel-Core-Tests.package/FLCreateClassSerializationTest.class/instance/testMaterializationDoesNotModifySerializedClass.st
@@ -3,7 +3,7 @@ testMaterializationDoesNotModifySerializedClass
 	"Tests that materialization does not change the source class."
 
 	| aClass materializedClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'var' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(var) ].
 
 	self serializer fullySerializeBehavior: aClass.
 	self serialize: aClass.
diff --git a/repository/Fuel-Core-Tests.package/FLFullBasicSerializationTest.class/instance/testCreateClassWithChangedSuperclassFormat.st b/repository/Fuel-Core-Tests.package/FLFullBasicSerializationTest.class/instance/testCreateClassWithChangedSuperclassFormat.st
index a053829..2bc90c7 100644
--- a/repository/Fuel-Core-Tests.package/FLFullBasicSerializationTest.class/instance/testCreateClassWithChangedSuperclassFormat.st
+++ b/repository/Fuel-Core-Tests.package/FLFullBasicSerializationTest.class/instance/testCreateClassWithChangedSuperclassFormat.st
@@ -3,11 +3,11 @@ testCreateClassWithChangedSuperclassFormat
 	"Tests issue #221"
 
 	| a b |
-	a := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'one' ].
+	a := self classFactory make: [ :aBuilder | aBuilder slots: #(one) ].
 	b := self classFactory make: [ :aBuilder |
 		     aBuilder
 			     superclass: a;
-			     slotsFromString: 'two' ].
+			     slots: #(two) ].
 	self serializer fullySerializeBehavior: b.
 	self serialize: {
 			b new.
diff --git a/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPostMaterializationActions.st b/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPostMaterializationActions.st
index 96548b8..7c0172d 100644
--- a/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPostMaterializationActions.st
+++ b/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPostMaterializationActions.st
@@ -4,7 +4,7 @@ testPostMaterializationActions
 	| aClass |
 	CompilationContext optionCleanBlockClosure ifTrue: [ ^ self skip ].
 
-	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariablesFromString: 'TestClassVariable TestClassVariable2' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariables: #(TestClassVariable TestClassVariable2) ].
 	self classFactory
 		silentlyCompile: 'postLoadMethod TestClassVariable := 1' in: aClass class;
 		silentlyCompile: 'postLoadMethod2 TestClassVariable := 2' in: aClass class;
diff --git a/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPreMaterializationActions.st b/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPreMaterializationActions.st
index 1d17804..b0a121f 100644
--- a/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPreMaterializationActions.st
+++ b/repository/Fuel-Core-Tests.package/FLFullHeaderSerializationTest.class/instance/testPreMaterializationActions.st
@@ -4,7 +4,7 @@ testPreMaterializationActions
 	| aClass |
 	CompilationContext optionCleanBlockClosure ifTrue: [ ^ self skip ].
 
-	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariablesFromString: 'TestClassVariable TestClassVariable2' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariables: #(TestClassVariable TestClassVariable2) ].
 	self classFactory
 		silentlyCompile: 'postLoadMethod TestClassVariable := 1' in: aClass class;
 		silentlyCompile: 'postLoadMethod2 TestClassVariable := 2' in: aClass class;
diff --git a/repository/Fuel-Core-Tests.package/FLGlobalTraitSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st b/repository/Fuel-Core-Tests.package/FLGlobalTraitSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
index 3e55dac..ea06445 100644
--- a/repository/Fuel-Core-Tests.package/FLGlobalTraitSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
+++ b/repository/Fuel-Core-Tests.package/FLGlobalTraitSerializationTest.class/instance/testCreateClassWithCreatedTraitWithInstanceVariable.st
@@ -5,13 +5,13 @@ testCreateClassWithCreatedTraitWithInstanceVariable
 	The trait has instance variables."
 
 	| aClass aTrait result materializedClass materializedTrait materializedObject |
-	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'ivar' ].
+	aClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(ivar) ].
 	self classFactory silentlyCompile: 'ivar: x ivar := x' in: aClass.
 	self classFactory silentlyCompile: 'ivar ^ ivar' in: aClass.
 	aTrait := self classFactory silentlyMake: [ :aBuilder |
 		          aBuilder
 			          beTrait;
-			          slotsFromString: 'traitIvar' ].
+			          slots: #(traitIvar) ].
 	self classFactory silentlyCompile: 'traitIvar: x traitIvar := x' in: aTrait.
 	self classFactory silentlyCompile: 'traitIvar ^ traitIvar' in: aTrait.
 	aClass addToComposition: aTrait.
diff --git a/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPostMaterializationActions.st b/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPostMaterializationActions.st
index 5b6f444..f9798e2 100644
--- a/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPostMaterializationActions.st
+++ b/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPostMaterializationActions.st
@@ -4,7 +4,7 @@ testPostMaterializationActions
 	| aClass |
 	CompilationContext optionCleanBlockClosure ifTrue: [ ^ self skip ].
 
-	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariablesFromString: 'TestClassVariable TestClassVariable2' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariables: #(TestClassVariable TestClassVariable2) ].
 	self classFactory
 		silentlyCompile: 'postLoadMethod TestClassVariable := 1' in: aClass class;
 		silentlyCompile: 'postLoadMethod2 TestClassVariable := 2' in: aClass class;
diff --git a/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPreMaterializationActions.st b/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPreMaterializationActions.st
index c925404..53f7618 100644
--- a/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPreMaterializationActions.st
+++ b/repository/Fuel-Core-Tests.package/FLHeaderSerializationTest.class/instance/testPreMaterializationActions.st
@@ -4,7 +4,7 @@ testPreMaterializationActions
 	| aClass |
 	CompilationContext optionCleanBlockClosure ifTrue: [ ^ self skip ].
 
-	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariablesFromString: 'TestClassVariable TestClassVariable2' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder sharedVariables: #(TestClassVariable TestClassVariable2) ].
 	self classFactory
 		silentlyCompile: 'postLoadMethod TestClassVariable := 1' in: aClass class;
 		silentlyCompile: 'postLoadMethod2 TestClassVariable := 2' in: aClass class;
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testClassWithCachedValueByNil.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testClassWithCachedValueByNil.st
index 3f263d1..3fd77e2 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testClassWithCachedValueByNil.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testClassWithCachedValueByNil.st
@@ -2,7 +2,7 @@ tests
 testClassWithCachedValueByNil
 
 	| aClassWithCachedValue result original |
-	aClassWithCachedValue := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'cache' ].
+	aClassWithCachedValue := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(cache) ].
 	self classFactory
 		silentlyCompile: 'cache ^cache' in: aClassWithCachedValue;
 		silentlyCompile: 'cache: x cache := x' in: aClassWithCachedValue;
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testObjectByProxyThatBecomesItsContent.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testObjectByProxyThatBecomesItsContent.st
index 4e43159..70f945a 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testObjectByProxyThatBecomesItsContent.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testObjectByProxyThatBecomesItsContent.st
@@ -3,7 +3,7 @@ testObjectByProxyThatBecomesItsContent
 	"Tests a substitution of an object by a proxy that becomes another object on materialization."
 
 	| aProxyClass result |
-	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slotsFromString: 'someState' ].
+	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder slots: #(someState) ].
 	self classFactory
 		silentlyCompile: 'initialize  someState := 5@1' in: aProxyClass;
 		silentlyCompile: 'fuelAccept: aVisitor
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTarget.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTarget.st
index 368caf8..579bd1d 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTarget.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTarget.st
@@ -2,7 +2,7 @@ tests
 testProxyByTarget
 
 	| aProxyClass result original |
-	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'Target' ].
+	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(Target) ].
 	self classFactory
 		silentlyCompile: 'target: x  Target := x' in: aProxyClass;
 		silentlyCompile: 'fuelAccept: aVisitor
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetAnalisysIsPropagated.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetAnalisysIsPropagated.st
index 46a4f9d..caac77f 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetAnalisysIsPropagated.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetAnalisysIsPropagated.st
@@ -2,7 +2,7 @@ tests
 testProxyByTargetAnalisysIsPropagated
 
 	| aProxyClass result pair original |
-	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'Target' ].
+	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(Target) ].
 	self classFactory
 		silentlyCompile: 'target: x  Target := x' in: aProxyClass;
 		silentlyCompile: 'fuelAccept: aVisitor
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetInsideObjectAndAnalisysIsPropagated.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetInsideObjectAndAnalisysIsPropagated.st
index 07f4c96..42b8372 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetInsideObjectAndAnalisysIsPropagated.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyByTargetInsideObjectAndAnalisysIsPropagated.st
@@ -2,7 +2,7 @@ tests
 testProxyByTargetInsideObjectAndAnalisysIsPropagated
 
 	| aProxyClass result original pair pairRoot |
-	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'Target' ].
+	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(Target) ].
 	self classFactory
 		silentlyCompile: 'target: x  Target := x' in: aProxyClass;
 		silentlyCompile: 'fuelAccept: aVisitor
diff --git a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyInsideObjectByTarget.st b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyInsideObjectByTarget.st
index f9e88e8..ca20961 100644
--- a/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyInsideObjectByTarget.st
+++ b/repository/Fuel-Core-Tests.package/FLHookedSubstitutionTest.class/instance/testProxyInsideObjectByTarget.st
@@ -2,7 +2,7 @@ tests
 testProxyInsideObjectByTarget
 
 	| aProxyClass result original pair |
-	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariablesFromString: 'Target' ].
+	aProxyClass := self classFactory silentlyMake: [ :aBuilder | aBuilder sharedVariables: #(Target) ].
 	self classFactory
 		silentlyCompile: 'target: x  Target := x' in: aProxyClass;
 		silentlyCompile: 'fuelAccept: aVisitor
diff --git a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testAllVariablesIgnored.st b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testAllVariablesIgnored.st
index 8818d4b..9bf7cda 100644
--- a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testAllVariablesIgnored.st
+++ b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testAllVariablesIgnored.st
@@ -2,7 +2,7 @@ tests
 testAllVariablesIgnored
 
 	| anObject result aClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a b' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a b) ].
 	self classFactory silentlyCompile: 'fuelIgnoredInstanceVariableNames ^#(a b)' in: aClass class.
 	anObject := aClass new
 		            instVarAt: 1 put: $A;
diff --git a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testIgnoredValueIsNotMaterialized.st b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testIgnoredValueIsNotMaterialized.st
index 3c21415..715cb11 100644
--- a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testIgnoredValueIsNotMaterialized.st
+++ b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testIgnoredValueIsNotMaterialized.st
@@ -2,7 +2,7 @@ tests
 testIgnoredValueIsNotMaterialized
 
 	| anObject materialized aClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a) ].
 	self classFactory silentlyCompile: 'fuelIgnoredInstanceVariableNames ^#(a)' in: aClass class.
 	anObject := aClass new
 		            instVarAt: 1 put: #A;
diff --git a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testOneIgnoredVariable.st b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testOneIgnoredVariable.st
index 8ddbe22..1d766d9 100644
--- a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testOneIgnoredVariable.st
+++ b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testOneIgnoredVariable.st
@@ -2,7 +2,7 @@ tests
 testOneIgnoredVariable
 
 	| anObject result aClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a b c' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a b c) ].
 	self classFactory silentlyCompile: 'fuelIgnoredInstanceVariableNames ^#(b)' in: aClass class.
 	anObject := aClass new
 		            instVarAt: 1 put: $A;
diff --git a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testTwoIgnoredVariables.st b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testTwoIgnoredVariables.st
index c879e19..63fe2db 100644
--- a/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testTwoIgnoredVariables.st
+++ b/repository/Fuel-Core-Tests.package/FLIgnoredVariablesTest.class/instance/testTwoIgnoredVariables.st
@@ -2,7 +2,7 @@ tests
 testTwoIgnoredVariables
 
 	| anObject result aClass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a b c' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a b c) ].
 	self classFactory silentlyCompile: 'fuelIgnoredInstanceVariableNames ^#(a c)' in: aClass class.
 	anObject := aClass new
 		            instVarAt: 1 put: $A;
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/redefined.with..st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/redefined.with..st
index 88673a2..db2e500 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/redefined.with..st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/redefined.with..st
@@ -4,4 +4,4 @@ redefined: aClass with: instanceVariableNames
 	^ self classFactory make: [ :aBuilder |
 		  aBuilder
 			  fillFor: aClass;
-			  slotsFromString: instanceVariableNames ]
\ No newline at end of file
+			  slots: instanceVariableNames ]
\ No newline at end of file
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testBadDestinationVariableRename.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testBadDestinationVariableRename.st
index dfd3ae9..ee0e8c5 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testBadDestinationVariableRename.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testBadDestinationVariableRename.st
@@ -2,7 +2,7 @@ tests-manual
 testBadDestinationVariableRename
 
 	| pointClass aPoint pointClassName |
-	pointClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'x y' ].
+	pointClass := self classFactory make: [ :aBuilder | aBuilder slots: #(x y) ].
 	pointClassName := pointClass name.
 	aPoint := pointClass new.
 
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testChangeInSuperclass.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testChangeInSuperclass.st
index 2984bc8..c93fba8 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testChangeInSuperclass.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testChangeInSuperclass.st
@@ -3,11 +3,11 @@ testChangeInSuperclass
 	"Tests that serializer tolarates when there is a change in the superclass between serialization and materialization"
 
 	| aClass aClassSubclass instance materializedInstance |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a b c' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a b c) ].
 	aClassSubclass := self classFactory make: [ :aBuilder |
 		                  aBuilder
 			                  superclass: aClass;
-			                  slotsFromString: 'd e' ].
+			                  slots: #(d e) ].
 
 	instance := aClassSubclass new.
 	instance instVarNamed: 'a' put: $A.
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassAndVariableRename.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassAndVariableRename.st
index 89b99ba..e777030 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassAndVariableRename.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassAndVariableRename.st
@@ -2,7 +2,7 @@ tests-manual
 testClassAndVariableRename
 
 	| pointClass aPoint resultPoint pointClassName |
-	pointClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'x y' ].
+	pointClass := self classFactory make: [ :aBuilder | aBuilder slots: #(x y) ].
 	pointClassName := pointClass name.
 	aPoint := pointClass new.
 	aPoint instVarNamed: 'x' put: 7.
@@ -10,7 +10,7 @@ testClassAndVariableRename
 
 	self serialize: aPoint.
 	self classFactory silentlyRename: pointClass to: (pointClassName , 'Renamed') asSymbol.
-	pointClass := self redefined: pointClass with: 'posY posX'.
+	pointClass := self redefined: pointClass with: #(posY posX).
 
 	self materializer migrateClassNamed: pointClassName toClass: pointClass variables: (Dictionary new
 			 at: 'x' put: 'posX';
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassRename.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassRename.st
index 40363ff..76aeec9 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassRename.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testClassRename.st
@@ -2,7 +2,7 @@ tests-manual
 testClassRename
 
 	| pointClass aPoint resultPoint pointClassName |
-	pointClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'x y' ].
+	pointClass := self classFactory make: [ :aBuilder | aBuilder slots: #(x y) ].
 	pointClassName := pointClass name.
 	aPoint := pointClass new.
 	aPoint instVarNamed: 'x' put: 7.
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testSuperclassChange.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testSuperclassChange.st
index ea0a96c..c514cde 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testSuperclassChange.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testSuperclassChange.st
@@ -3,12 +3,12 @@ testSuperclassChange
 	"Tests that serializer tolarates when the superclass changed between serialization and materialization"
 
 	| aClass aClassSubclass instance materializedInstance anotherSuperclass |
-	aClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'a b c' ].
+	aClass := self classFactory make: [ :aBuilder | aBuilder slots: #(a b c) ].
 	aClassSubclass := self classFactory make: [ :aBuilder |
 		                  aBuilder
 			                  superclass: aClass;
-			                  slotsFromString: 'd e' ].
-	anotherSuperclass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'x' ].
+			                  slots: #(d e) ].
+	anotherSuperclass := self classFactory make: [ :aBuilder | aBuilder slots: #(x) ].
 
 	instance := aClassSubclass new.
 	instance instVarNamed: 'a' put: $A.
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableInsertion.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableInsertion.st
index 370665d..8ffdb10 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableInsertion.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableInsertion.st
@@ -3,13 +3,13 @@ testVariableInsertion
 	"Tests that serializer tolarates when there is a new instance variable on materialization"
 
 	| pairClass aPair resultPair |
-	pairClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'left right' ].
+	pairClass := self classFactory make: [ :aBuilder | aBuilder slots: #(left right) ].
 	aPair := pairClass new.
 	aPair instVarAt: 1 put: $A.
 	aPair instVarAt: 2 put: $B.
 
 	self serialize: aPair.
-	self redefined: pairClass with: 'left middle right'.
+	self redefined: pairClass with: #(left middle right).
 	resultPair := self materialized.
 
 	self assert: $A equals: (resultPair instVarAt: 1).
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableOrderChange.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableOrderChange.st
index 316854b..951466a 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableOrderChange.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableOrderChange.st
@@ -3,13 +3,13 @@ testVariableOrderChange
 	"Tests that serializer tolarates when the order in the instance variables changed between serialization and materialization"
 
 	| pairClass aPair resultPair |
-	pairClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'left right' ].
+	pairClass := self classFactory make: [ :aBuilder | aBuilder slots: #(left right) ].
 	aPair := pairClass new.
 	aPair instVarAt: 1 put: $A.
 	aPair instVarAt: 2 put: $B.
 
 	self serialize: aPair.
-	self redefined: pairClass with: 'right left'.
+	self redefined: pairClass with: #(right left).
 	resultPair := self materialized.
 
 	self assert: $B equals: (resultPair instVarAt: 1).
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRemoved.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRemoved.st
index 3730098..dee1671 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRemoved.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRemoved.st
@@ -3,13 +3,13 @@ testVariableRemoved
 	"Tests that serializer tolarates when an instance variable is missing on materialization"
 
 	| pairClass aPair resultPair |
-	pairClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'left right' ].
+	pairClass := self classFactory make: [ :aBuilder | aBuilder slots: #(left right) ].
 	aPair := pairClass new.
 	aPair instVarAt: 1 put: $A.
 	aPair instVarAt: 2 put: $B.
 
 	self serialize: aPair.
-	self redefined: pairClass with: 'right'.
+	self redefined: pairClass with: #(right).
 	resultPair := self materialized.
 
 	self assert: $B equals: (resultPair instVarAt: 1)
\ No newline at end of file
diff --git a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRename.st b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRename.st
index e01ad3c..b9a200f 100644
--- a/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRename.st
+++ b/repository/Fuel-Core-Tests.package/FLMigrationTest.class/instance/testVariableRename.st
@@ -2,14 +2,14 @@ tests-manual
 testVariableRename
 
 	| pointClass aPoint resultPoint pointClassName |
-	pointClass := self classFactory make: [ :aBuilder | aBuilder slotsFromString: 'x y' ].
+	pointClass := self classFactory make: [ :aBuilder | aBuilder slots: #(x y) ].
 	pointClassName := pointClass name.
 	aPoint := pointClass new.
 	aPoint instVarNamed: 'x' put: 7.
 	aPoint instVarNamed: 'y' put: 11.
 
 	self serialize: aPoint.
-	self redefined: pointClass with: 'posY posX'.
+	self redefined: pointClass with: #(posY posX).
 
 	self materializer migrateClassNamed: pointClassName variables: (Dictionary new
 			 at: 'x' put: 'posX';