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

"{ NameSpace: Smalltalk }"

PEGFsaAbstractDeterminizator subclass:#PEGFsaSequenceDeterminizator

	instanceVariableNames:''

	classVariableNames:''

	poolDictionaries:''

	category:'PetitCompiler-FSA'

!

!PEGFsaSequenceDeterminizator methodsFor:'determinization'!

determinize

    super determinize.

    self markFailures.

    fsa removePriorities.

!

markFailures

    fsa finalStates do: [ :fs |

        | priority |

        priority := fs priority.

        fs reachableStates do: [ :rs |

            (rs hasPriority and: [ (rs priority > fs priority) and: [ rs isFinal not ] ]) ifTrue: [ 

                rs failure: true.

                rs final: true.

            ]

        ]

    ]

! !

!PEGFsaSequenceDeterminizator methodsFor:'joining'!

joinInfo: info with: anotherInfo into: newInfo

    (info hasEqualPriorityTo: anotherInfo) ifTrue: [ 

        newInfo final: (info isFinal or: [ anotherInfo isFinal ]).

        newInfo priority: info priority.	

        ^ self

    ].

    (info hasHigherPriorityThan: anotherInfo) ifTrue: [ 

 		newInfo priority: info priority.	

        newInfo failure: info isFsaFailure.

        newInfo final: info isFinal.

        ^ self

    ].

    newInfo priority: anotherInfo priority.

    newInfo failure: anotherInfo isFsaFailure.

    newInfo final: anotherInfo isFinal.

!

joinRetval: state with: anotherState into: newState

    "Different retvals cannot merge their info"

    self assert: (state hasDifferentRetvalThan: anotherState) not. 

    self assert: state retval == anotherState retval.

    newState retval: state retval.

!

joinState: state with: anotherState

    self assert: state isMultivalue not.

    self assert: anotherState isMultivalue not.

    ^ super joinState: state with: anotherState

!

joinTransitions: state with: anotherState into: newState

    self assert: newState isMultivalue not.

    newState hasPriority ifFalse: [ 

        newState transitions addAll: (state transitions collect: #copy).

        newState transitions addAll: (anotherState transitions collect: #copy).

        ^ self

    ].

    self assert: newState hasPriority.

    "This is a part when low priority branches are cut-out"

    (state priority == newState priority) ifTrue: [ 

        newState transitions addAll: (state transitions collect: #copy).

    ] ifFalse: [

        newState transitions addAll: (state transitions select: [ :t | t priority > newState priority ] thenCollect: #copy)

    ].

    (anotherState priority == newState priority) ifTrue: [ 

        newState transitions addAll: (anotherState transitions collect: #copy).

    ] ifFalse: [

        newState transitions addAll: (anotherState transitions select: [ :t | t priority > newState priority ] thenCollect: #copy)

    ].

    newState mergeTransitions.

! !