PetitCommonMark/software/petitislands/PPParser.extension.st

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Extension { #name : 'PPParser' }
{ #category : '*petitislands' }
PPParser >> acceptsEpsilon [
"
return true, if parser can accepts epsilon without a failure.
Use #neverFails if parser never fail, no matter what is the input.
The #isNullable semantics is a mystery for me. I think it is something
like acceptsEpsilon and is used for first/set computation.
"
^ self subclassResponsibility
]
{ #category : '*petitislands' }
PPParser >> acceptsEpsilonOpenSet: set [
"private helper for acceptsEmpsilon that makes sure to avoid cycles (using open set)"
self children isEmpty ifTrue: [ ^ self acceptsEpsilon ].
self shouldBeImplemented .
]
{ #category : '*petitislands' }
PPParser >> isIslandBorder [
^ self subclassResponsibility
]
{ #category : '*petitislands' }
PPParser >> isIslandBorderOpenSet: set [
"private helper for acceptsEmpsilon that makes sure to avoid cycles (using open set)"
self children isEmpty ifTrue: [ ^ self isIslandBorder ].
self shouldBeImplemented .
]
{ #category : '*petitislands' }
PPParser >> isWater [
^ false
]
{ #category : '*petitislands' }
PPParser >> island [
self halt: 'deprecated'.
^ self sea
]
{ #category : '*petitislands' }
PPParser >> island: water [
self halt: 'deprecated'.
^ self sea: water
]
{ #category : '*petitislands' }
PPParser >> next: context [
^ PPChoiceParser withAll: (self nextSet: context)
]
{ #category : '*petitislands' }
PPParser >> nextSet: aPPContext [
^ aPPContext root nextSets at: self.
]
{ #category : '*petitislands' }
PPParser >> nextSets [
| nextSets |
nextSets := IdentityDictionary new.
self allParsersDo: [ :each | nextSets at: each put: IdentitySet new ].
(nextSets at: self) add: PPSentinel instance.
[ | changed |
changed := false.
nextSets keysAndValuesDo: [:parser :next |
changed := (parser
nextSets: nextSets
into: next) or: [ changed ].
].
changed ] whileTrue.
^ nextSets
]
{ #category : '*petitislands' }
PPParser >> nextSets: aNextDictionary into: aSet [
"return true/false, if something has changed or not...."
| childSet change tally |
change := false.
self children do: [:each |
childSet := aNextDictionary at: each.
tally := childSet size.
childSet addAll: aSet.
change := change or: [ tally ~= childSet size ].
].
^ change
]
{ #category : '*petitislands' }
PPParser >> nonEmpty [
^ PPNonEmptyParser on: self
]
{ #category : '*petitislands' }
PPParser >> previous [
^ PPPreviousParser on: self
]
{ #category : '*petitislands' }
PPParser >> sea [
| island |
island := PPSea new
island: self;
yourself.
^ island memoized
]
{ #category : '*petitislands' }
PPParser >> sea: water [
^ self sea
water: water;
yourself
]