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

"{ NameSpace: Smalltalk }"

Object subclass:#PPCScanner

	instanceVariableNames:'matches stream maxPriority currentChar'

	classVariableNames:''

	poolDictionaries:''

	category:'PetitCompiler-Scanner'

!

!PPCScanner methodsFor:'accessing'!

stream

    ^ stream

!

stream: anObject

    stream := anObject

! !

!PPCScanner methodsFor:'as yet unclassified'!

recordMatch: match 

 	^ self recordMatch: match priority: 0

!

recordMatch: match priority: currentPriority

    (maxPriority < currentPriority) ifTrue: [ 

        matches := IdentityDictionary new.

        maxPriority := currentPriority.

    ].

    (maxPriority == currentPriority) ifTrue: [ 

     	matches at: match put: stream position

 	].

!

return

    ^ self returnPriority: SmallInteger minVal.

!

returnPriority: priority

    (maxPriority < priority) ifTrue: [ 

        ^ IdentityDictionary new

    ].

    ^ matches keysAndValuesRemove: [ :key :value | key class == PEGFsaFailure ]

! !

!PPCScanner methodsFor:'initialization'!

initialize

    super initialize.

    matches := IdentityDictionary new.	

    maxPriority := SmallInteger minVal.

! !

!PPCScanner methodsFor:'scanning'!

consumeConditionally: character

    ^ (stream peek == character) ifTrue: [ stream next. true ] ifFalse: [ false ]

!

next

    stream next

!

peek

    ^ currentChar

!

peekBetween: start and: stop

    (currentChar == nil) ifTrue: [ ^ false ].

    ^ start <= currentChar codePoint and: [ currentChar codePoint <= stop ]

!

step

    currentChar := stream next

! !