"{ Package: 'stx:goodies/petitparser' }"
PPDelegateParser subclass:#PPMemoizedParser
instanceVariableNames:'stream buffer'
classVariableNames:''
poolDictionaries:''
category:'PetitParser-Parsers'
!
PPMemoizedParser comment:'A memoized parser, for refraining redundant computations.
Instance Variables:
stream <PositionableStream> The stream of the associated memento objects.
buffer <Array of: PPMemento> The buffer of memento objects.
'
!
!PPMemoizedParser methodsFor:'operations'!
memoized
"Ther is no point in memoizing more than once."
^ self
! !
!PPMemoizedParser methodsFor:'parsing'!
parseOn: aStream
| memento |
stream == aStream
ifFalse: [ self reset: aStream ].
memento := (buffer at: stream position + 1)
ifNil: [ buffer at: stream position + 1 put: PPMemento new ].
memento position isNil
ifTrue: [
memento result: (stream size - stream position + 2 < memento count
ifTrue: [ PPFailure message: 'overflow' at: stream position ]
ifFalse: [ memento increment. parser parseOn: stream ]).
memento position: stream position ]
ifFalse: [ stream position: memento position ].
^ memento result
! !
!PPMemoizedParser methodsFor:'private'!
reset: aStream
stream := aStream.
buffer := Array new: aStream size + 1
! !
!PPMemoizedParser class methodsFor:'documentation'!
version_SVN
^ '$Id: PPMemoizedParser.st,v 1.2 2012-01-13 11:22:50 cg Exp $'
! !