Do not use RBProgramNode>>variableNodesDo: as this method is not present in Pharo.
Use local helper method instead.
"{ Package: 'stx:goodies/petitparser' }"
"{ NameSpace: Smalltalk }"
PPDelegateParser subclass:#PPConditionalParser
instanceVariableNames:'block'
classVariableNames:''
poolDictionaries:''
category:'PetitParser-Parsers'
!
!PPConditionalParser class methodsFor:'as yet unclassified'!
on: aPPParser block: block
^ (PPConditionalParser on: aPPParser)
block: block;
yourself
! !
!PPConditionalParser methodsFor:'accessing'!
block: aBlock
block := aBlock
! !
!PPConditionalParser methodsFor:'parsing'!
parseOn: aPPContext
^ (block value: aPPContext)
ifTrue: [ parser parseOn: aPPContext ]
ifFalse: [ PPFailure message: block asString, ' was not evaluated to true.' context: aPPContext ]
! !