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

"{ NameSpace: Smalltalk }"

Object subclass:#PPCDistinctScanner

	instanceVariableNames:'position match matchPosition currentChar context returnBlock'

	classVariableNames:''

	poolDictionaries:''

	category:'PetitCompiler-Scanner'

!

!PPCDistinctScanner methodsFor:'accessing-private'!

getMatch

    ^ match

!

position

    "returns the start position before the scan method..."

    ^ position

!

position: anObject

    position := matchPosition := anObject

!

setMatch: value

    match := value

!

stream

    ^ context

!

stream: anObject

    context := anObject

! !

!PPCDistinctScanner methodsFor:'initialization'!

initialize

    super initialize.

    match := nil.

    position := 0.

    matchPosition := 0.

!

resetDistinct

! !

!PPCDistinctScanner methodsFor:'memoization'!

remember

    ^ position

!

restore: restorePosition

    context position: (matchPosition := position := restorePosition).

    match := nil

! !

!PPCDistinctScanner methodsFor:'results'!

polyResult

    | dictionary |

    dictionary := IdentityDictionary new.

    match isNil ifFalse: [ 

        dictionary at: match put: matchPosition.

    ].

    ^ dictionary

!

recordDistinctFailure

    self flag: 'Potential bug? What if there is something after the failure? Might that happen for distinct parser?'.

    match := nil.

    matchPosition := position.

    context position: position.

    ^ false

!

recordDistinctMatch: matchValue

    match := matchValue.

    matchPosition := context position.

    ^ true

!

recordDistinctMatch: matchValue offset: offset

    match := matchValue.

    currentChar isNil ifFalse: [ 

        matchPosition := context position - offset.

    ] ifTrue: [ 

        matchPosition := context position.

    ].

    ^ true

!

result

    ^ match

!

resultPosition

    ^ matchPosition

!

returnDistinct

"

    match isNil ifTrue: [ 

        self assert: matchPosition == position

    ].

"

    context position: matchPosition.

    ^ match isNotNil

! !

!PPCDistinctScanner methodsFor:'scanning'!

back

    currentChar isNil ifFalse: [ 

        context skip: -1

    ]

!

peekBetween: start and: stop

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

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

!

step

    currentChar := context next

! !