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

!PPChoiceParser methodsFor:'*petitislands'!

acceptsEpsilonOpenSet: set

	set add: self.

	^ self children anySatisfy: [:e | e acceptsEpsilonOpenSet: set ].

! !

!PPContext methodsFor:'*petitislands'!

waterPosition

	^ self globalAt:  #waterPosition ifAbsentPut: [ nil ]

! !

!PPContext methodsFor:'*petitislands'!

waterPosition: position

	^ self globalAt:  #waterPosition put: position

! !

!PPDelegateParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ parser acceptsEpsilonOpenSet: (IdentitySet with: self).

! !

!PPDelegateParser methodsFor:'*petitislands'!

acceptsEpsilonOpenSet: set

	(set includes: parser) ifFalse: [ 

		set add: parser.

		^ parser acceptsEpsilonOpenSet: set 

	].

	^ false

! !

!PPEpsilonParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ true

! !

!PPListParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ self acceptsEpsilonOpenSet: IdentitySet new.

! !

!PPLiteralParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ false

! !

!PPOptionalParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ true

! !

!PPOptionalParser methodsFor:'*petitislands'!

acceptsEpsilonOpenSet: set

	^ true

! !

!PPParser methodsFor:'*petitislands'!

acceptsEpsilon

	"return true, if parser can accept epsilon without failure"

	^ self subclassResponsibility

! !

!PPParser methodsFor:'*petitislands'!

acceptsEpsilonOpenSet: set

	"private helper for acceptsEmpsilon that makes sure to avoid cycles (using open set)"

	self children isEmpty ifTrue: [ ^ self acceptsEpsilon ].

	self shouldBeImplemented .

! !

!PPParser methodsFor:'*petitislands'!

island

	^ PPIsland new

		island: self;

		yourself;

		memoized

! !

!PPParser methodsFor:'*petitislands'!

island: water

	^ PPIsland new

		island: self;

		water: water;

		yourself;

		memoized

! !

!PPParser methodsFor:'*petitislands'!

nextSets

	| nextSets |

	nextSets := IdentityDictionary new.

	self allParsersDo: [ :each | nextSets at: each put: IdentitySet new ].

	(nextSets at: self) add: PPSentinel instance.

	[ 	| changed |

		changed := false.

		nextSets keysAndValuesDo: [:parser :next |

			changed := (parser 

				nextSets: nextSets

				into: next) or: [ changed ].

		].

		changed ] whileTrue.

	^ nextSets

! !

!PPParser methodsFor:'*petitislands'!

nextSets: aNextDictionary into: aSet

	"return true/false, if something has changed or not...."

	| childSet change tally |

	change := false.

	self children do: [:each | 

		childSet := aNextDictionary at: each.

		tally := childSet size.

		childSet addAll: aSet.

		change := change or: [ tally ~= childSet size ].

	].

	^ change

! !

!PPPredicateParser methodsFor:'*petitislands'!

acceptsEpsilon

	^ false

! !

!PPRepeatingParser methodsFor:'*petitislands'!

nextSets: aNextDictionary into: aSet

	| tally childSet change |

	change := super nextSets: aNextDictionary  into: aSet.

	childSet := aNextDictionary at: parser.

	tally := aSet size.

	childSet add: parser.

	^ change or: [ tally ~= aSet size ].

! !

!PPSequenceParser methodsFor:'*petitislands'!

acceptsEpsilonOpenSet: set

	set add: self.

	^ self children allSatisfy: [:e | e acceptsEpsilonOpenSet: set ]

! !

!PPSequenceParser methodsFor:'*petitislands'!

nextSets: aNextDictionary into: aSet

	| nextSet eachNextSet change tally |

	nextSet := aSet copy.

	change := false.

	self children reverseDo: [:each |

		eachNextSet := aNextDictionary at: each.	

		tally := eachNextSet size.

		eachNextSet addAll: nextSet.

		change := change or: [ tally ~= eachNextSet size ].

		each acceptsEpsilon ifTrue: [

			nextSet add: each.

		] ifFalse: [

			nextSet := IdentitySet with: each.

		].

	].

	^ change

! !

!stx_goodies_petitparser_islands class methodsFor:'documentation'!

extensionsVersion_HG

    ^ '$Changeset: <not expanded> $'

! !