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

     2 

     3 "{ NameSpace: Smalltalk }"

     4 

     5 PPCRewritingVisitor subclass:#PPCMergingVisitor

     6 	instanceVariableNames:'nodeSet'

     7 	classVariableNames:''

     8 	poolDictionaries:''

     9 	category:'PetitCompiler-Visitors'

    10 !

    11 

    12 !PPCMergingVisitor methodsFor:'as yet unclassified'!

    13 

    14 equivalentNode: node

    15 	^  nodeSet detect: [ :e | e = node ]

    16 !

    17 

    18 hasEquivalentNode: node

    19 	^ nodeSet includes: node

    20 !

    21 

    22 initialize

    23 	super initialize.

    24 	

    25 	nodeSet := Set new

    26 !

    27 

    28 store: node

    29 	self assert: (self hasEquivalentNode: node) not.

    30 	nodeSet add: node

    31 !

    32 

    33 visitNode: node

    34 	super visitNode: node.

    35 	

    36 	(self hasEquivalentNode: node) ifTrue: [

    37 		self change.

    38 		^ self equivalentNode: node

    39 	] ifFalse: [  

    40 		self store: node

    41 	].

    42 

    43 	^ node

    44 ! !

    45