--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/compiler/PPCContextMemento.st	Sun Oct 26 01:03:31 2014 +0000
@@ -0,0 +1,115 @@
+"{ Package: 'stx:goodies/petitparser/compiler' }"
+
+Object subclass:#PPCContextMemento
+	instanceVariableNames:'position properties'
+	classVariableNames:''
+	poolDictionaries:''
+	category:'PetitCompiler-Context'
+!
+
+PPCContextMemento comment:''
+!
+
+!PPCContextMemento methodsFor:'accessing'!
+
+position
+	^ position
+!
+
+position: anInteger
+	position := anInteger 
+! !
+
+!PPCContextMemento methodsFor:'accessing - properties'!
+
+hasProperty: aKey
+	"Test if the property aKey is present."
+	
+	^ properties notNil and: [ properties includesKey: aKey ]
+!
+
+keysAndValuesDo: aBlock
+	properties ifNil: [ ^ self ].
+	properties keysAndValuesDo: [ :key :value | aBlock value: key value: value copy ] 
+!
+
+propertiesSize
+	properties ifNil: [ ^ 0 ].
+	^ properties size.
+!
+
+propertyAt: aKey
+	"Answer the property value associated with aKey."
+	
+	^ self propertyAt: aKey ifAbsent: [ self error: 'Property not found' ]
+!
+
+propertyAt: aKey ifAbsent: aBlock
+        "Answer the property value associated with aKey or, if aKey isn't found, answer the result of evaluating aBlock."
+
+        properties isNil
+                ifTrue: [ ^ aBlock value ]
+                ifFalse: [ 
+                        (properties includesKey: aKey) ifTrue: [ 
+                                ^ (properties at: aKey) copy
+                        ].
+                        ^ aBlock value
+                ]
+
+    "Created: / 26-10-2014 / 01:23:09 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+!
+
+propertyAt: aKey ifAbsentPut: aBlock
+	"Answer the property associated with aKey or, if aKey isn't found store the result of evaluating aBlock as new value."
+	
+	^ self propertyAt: aKey ifAbsent: [ self propertyAt: aKey put: aBlock value ]
+!
+
+propertyAt: aKey put: anObject
+	"Set the property at aKey to be anObject. If aKey is not found, create a new entry for aKey and set is value to anObject. Answer anObject."
+
+	^ (properties ifNil: [ properties := Dictionary new: 1 ])
+		at: aKey put: (anObject copy)
+!
+
+removeProperty: aKey
+	"Remove the property with aKey. Answer the property or raise an error if aKey isn't found."
+	
+	^ self removeProperty: aKey ifAbsent: [ self error: 'Property not found' ]
+!
+
+removeProperty: aKey ifAbsent: aBlock
+	"Remove the property with aKey. Answer the value or, if aKey isn't found, answer the result of evaluating aBlock."
+	
+	| answer |
+	properties isNil ifTrue: [ ^ aBlock value ].
+	answer := properties removeKey: aKey ifAbsent: aBlock.
+	properties isEmpty ifTrue: [ properties := nil ].
+	^ answer
+! !
+
+!PPCContextMemento methodsFor:'comparing'!
+
+= anObject
+	
+	(self == anObject) ifTrue: [ ^ true ].
+	(anObject class = PPCContextMemento) ifFalse: [ ^ false ].
+	
+	(anObject position = position) ifFalse: [ ^ false ].
+
+	(self propertiesSize = anObject propertiesSize) ifFalse: [ ^ false ].
+
+	self keysAndValuesDo: [ :key :value |
+		(anObject hasProperty: key) ifFalse: [ ^ false ].
+		((anObject propertyAt: key) = value) ifFalse: [ ^ false ]. 
+ 	].
+	
+	^ true.
+!
+
+hash
+        ^ position hash bitXor: properties hash.
+
+    "Modified: / 26-10-2014 / 01:46:37 / Jan Vrany <jan.vrany@fit.cvut.cz>"
+! !
+