Class {
	#name : 'PPCChoiceOptimizationVisitor',
	#superclass : 'PPCRewritingVisitor',
	#category : 'PetitCompiler-Visitors'
}

{ #category : 'visiting' }
PPCChoiceOptimizationVisitor >> rejectDuplicateChildren: node [
	| seen newChildren |
	seen := IdentitySet new.
	newChildren := OrderedCollection new.
	node children do: [ :child | 
		(seen includes: child) ifFalse: [  
			newChildren add: child
		].
		seen add: child
	].
	^ newChildren

]

{ #category : 'visiting' }
PPCChoiceOptimizationVisitor >> visitChoiceNode: node [
	self visitChildren: node.

	"Remove the identical children"
	node children: 	(self rejectDuplicateChildren: node).
	
	(node children size = 1) ifTrue: [ 
		^ node firstChild
	].

	^ node
]