"{ Package: 'stx:goodies/petitparser' }"

Object subclass:#PPContextMemento

	instanceVariableNames:'stream position properties'

	classVariableNames:''

	poolDictionaries:''

	category:'PetitParser-Core'

!

!PPContextMemento methodsFor:'accessing'!

position

	^ position

!

position: anInteger

	position := anInteger 

!

stream

	^ stream

!

stream: aStream

	stream := aStream

! !

!PPContextMemento 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

		]

!

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

! !

!PPContextMemento methodsFor:'comparing'!

= anObject

	(self == anObject) ifTrue: [ ^ true ].

	(anObject class = PPContextMemento) ifFalse: [ ^ false ].

	(anObject stream == stream) 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: stream hash) bitXor: properties hash.

! !