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

"{ NameSpace: Smalltalk }"

Object subclass:#PPParser

	instanceVariableNames:'properties'

	classVariableNames:''

	poolDictionaries:''

	category:'PetitParser-Parsers'

!

!PPParser class methodsFor:'instance creation'!

named: aString

	^ self new name: aString

!

new

	^ self basicNew initialize

! !

!PPParser methodsFor:'accessing'!

children

	"Answer a set of child parsers that could follow the receiver."

	^ #()

!

name

	"Answer the production name of the receiver."

	^ self propertyAt: #name ifAbsent: [ nil ]

!

name: aString

	self propertyAt: #name put: aString

! !

!PPParser methodsFor:'accessing-properties'!

hasProperty: aKey

	"Test if the property aKey is present."

	^ properties notNil and: [ properties includesKey: aKey ]

!

propertyAt: aKey

	"Answer the property value associated with aKey."

	^ self propertyAt: aKey ifAbsent: [ self error: 'Property not found' ]

!

propertyAt: aKey ifAbsent: aBlock

	"Answer the property value associated with aKey or, if aKey isn't found, answer the result of evaluating aBlock."

	^ properties isNil

		ifTrue: [ aBlock value ]

		ifFalse: [ properties at: aKey ifAbsent: aBlock ]

!

propertyAt: aKey ifAbsentPut: aBlock

	"Answer the property associated with aKey or, if aKey isn't found store the result of evaluating aBlock as new value."

	^ self propertyAt: aKey ifAbsent: [ self propertyAt: aKey put: aBlock value ]

!

propertyAt: aKey put: anObject

	"Set the property at aKey to be anObject. If aKey is not found, create a new entry for aKey and set is value to anObject. Answer anObject."

	^ (properties ifNil: [ properties := Dictionary new: 1 ])

		at: aKey put: anObject

!

removeProperty: aKey

	"Remove the property with aKey. Answer the property or raise an error if aKey isn't found."

	^ self removeProperty: aKey ifAbsent: [ self error: 'Property not found' ]

!

removeProperty: aKey ifAbsent: aBlock

	"Remove the property with aKey. Answer the value or, if aKey isn't found, answer the result of evaluating aBlock."

	| answer |

	properties isNil ifTrue: [ ^ aBlock value ].

	answer := properties removeKey: aKey ifAbsent: aBlock.

	properties isEmpty ifTrue: [ properties := nil ].

	^ answer

! !

!PPParser methodsFor:'context'!

parse: anObject withContext: aPPContext

	"Parse anObject with the receiving parser and answer the parse-result or an instance of PPFailure."

	aPPContext stream: anObject asPetitStream.

	^ self parseWithContext: aPPContext.

!

parseWithContext: context

	| result |

	context initializeFor: self.

	result := self parseOn: context.

	"Return the furthest failure, it gives better results than the last failure"

	(result isPetitFailure and: [ context furthestFailure notNil]) 

		ifTrue: [ ^ context furthestFailure ].

	^ result

!

updateContext: aPPContext

	"nothing to do"

! !

!PPParser methodsFor:'converting'!

asParser

	"Answer the receiving parser."

	^ self

! !

!PPParser methodsFor:'copying'!

postCopy

	super postCopy.

	properties := properties copy

! !

!PPParser methodsFor:'enumerating'!

allParsers

	"Answer all the parse nodes of the receiver."

	| result |

	result := OrderedCollection new.

	self allParsersDo: [ :parser | result addLast: parser ].

	^ result

!

allParsersDo: aBlock

	"Iterate over all the parse nodes of the receiver."

	self allParsersDo: aBlock seen: IdentitySet new

!

allParsersDo: aBlock seen: aSet

	"Iterate over all the parse nodes of the receiver, do not visit and follow the ones contained in aSet."

	(aSet includes: self)

		ifTrue: [ ^ self ].

	aSet add: self.

	aBlock value: self.

	self children

		do: [ :each | each allParsersDo: aBlock seen: aSet ]

! !

!PPParser methodsFor:'initialization'!

initialize

! !

!PPParser methodsFor:'operations'!

, aParser 

	"Answer a new parser that parses the receiver followed by aParser."

	^ PPSequenceParser with: self with: aParser

!

/ aParser 

	"Answer a new parser that parses the receiver, if the receiver fails try with aParser (ordered-choice)."

	^ PPChoiceParser with: self with: aParser

!

and

	"Answer a new parser (logical and-predicate) that succeeds whenever the receiver does, but never consumes input."

	^ PPAndParser on: self

!

def: aParser

	"Redefine the receiver as the argument aParser. This method is useful when defining recursive parsers: instantiate a PPUnresolvedParser and later redefine it with another one."

	^ self becomeForward: (aParser name: self name)

!

end

	"Answer a new parser that succeeds at the end of the input and return the result of the receiver."

	^ PPEndOfInputParser on: self

!

memoized

	"Answer a new memoized parser, for refraining redundant computations. This ensures polynomial time O(n^4) for left-recursive grammars and O(n^3) for non left-recursive grammars in the worst case. Not necessary for most grammars that are carefully written and in O(n) anyway."

	^ PPMemoizedParser on: self

!

negate

        "Answer a new parser consumes any input token but the receiver."

        ^ self not , #any asParser ==> #second

!

not

	"Answer a new parser (logical not-predicate) that succeeds whenever the receiver fails, but never consumes input."

	^ PPNotParser on: self

!

optional

	"Answer a new parser that parses the receiver, if possible."

	^ PPOptionalParser on: self

!

times: anInteger

	"Answer a new parser that parses the receiver exactly anInteger times."

	^ self min: anInteger max: anInteger

!

wrapped

	"Answer a new parser that is simply wrapped."

	^ PPDelegateParser on: self

!

| aParser

	"Answer a new parser that either parses the receiver or aParser. Fail if both pass or fail (exclusive choice, unordered choice)."

	^ (self not , aParser) / (aParser not , self) ==> #second

! !

!PPParser methodsFor:'operations-convenience'!

delimitedBy: aParser

	"Answer a new parser that parses the receiver one or more times, separated and possibly ended by aParser."

	^ (self separatedBy: aParser) , (aParser optional) ==> [ :node |

		node second isNil

			ifTrue: [ node first ]

			ifFalse: [ node first copyWith: node second ] ]

!

separatedBy: aParser

	"Answer a new parser that parses the receiver one or more times, separated by aParser."

	^ (PPSequenceParser with: self with: (PPSequenceParser with: aParser with: self) star) ==> [ :nodes |

		| result |

		result := Array new: 2 * nodes second size + 1.

		result at: 1 put: nodes first.

		nodes second 

			keysAndValuesDo: [ :index :pair | result replaceFrom: 2 * index to: 2 * index + 1 with: pair startingAt: 1 ].

		result ]

! !

!PPParser methodsFor:'operations-mapping'!

==> aBlock

	"Answer a new parser that performs aBlock as action handler on success."

	^ PPActionParser on: self block: aBlock

!

answer: anObject

	"Answer a new parser that always returns anObject from a successful parse."

	^ self ==> [ :nodes | anObject ]

!

flatten

	"Answer a new parser that flattens the underlying collection."

	^ PPFlattenParser on: self

!

token

	"Answer a new parser that transforms the input to a token."

	^ PPTokenParser on: self

!

token: aTokenClass

	"Answer a new parser that transforms the input to a token of class aTokenClass."

	^ self token tokenClass: aTokenClass

!

trim

	"Answer a new parser that consumes spaces before and after the receiving parser."

	^ self trimSpaces

! !

!PPParser methodsFor:'operators'!

// aParser 

	"

		Answer a new parser that parses the receiver, if the receiver fails try with aParser (ordered-choice).

		If the receiver passes, limit must pass as well.

	"

	^ PPLimitedChoiceParser with: self with: aParser

!

if: aBlock

	^ PPConditionalParser on: self block: aBlock

! !

!PPParser methodsFor:'operators-convenience'!

withoutSeparators

	"Filters out the separators from a parse result produced by one of the productions #delimitedBy: or #separatedBy:."

	^ self ==> [ :items |

		| result |

		result := Array new: items size + 1 // 2.

		1 to: result size do: [ :index | result at: index put: (items at: 2 * index - 1) ].

		result ]

! !

!PPParser methodsFor:'operators-mapping'!

>=> aBlock

	"Answer a new parser that wraps the receiving parser with a two argument block. The first argument is the parsed stream, the second argument a continuation block on the delegate parser."

	^ PPWrappingParser on: self block: aBlock

!

foldLeft: aBlock

	"Answer a new parser that that folds the result of the receiver from left-to-right into aBlock. The argument aBlock must take two or more arguments."

	| size args |

	size := aBlock numArgs.

	args := Array new: size.

	^ self ==> [ :nodes |

		args at: 1 put: nodes first.

		2 to: nodes size by: size - 1 do: [ :index |

			args

				replaceFrom: 2 to: size with: nodes startingAt: index;

				at: 1 put: (aBlock valueWithArguments: args) ].

		args first ]

!

foldRight: aBlock

	"Answer a new parser that that folds the result of the receiver from right-to-left into aBlock. The argument aBlock must take two or more arguments."

	| size args |

	size := aBlock numArgs.

	args := Array new: size.

	^ self ==> [ :nodes |

		args at: size put: nodes last.

		nodes size - size + 1 to: 1 by: 1 - size do: [ :index |

			args

				replaceFrom: 1 to: size - 1 with: nodes startingAt: index;

				at: size put: (aBlock valueWithArguments: args) ].

		args at: size ]

!

map: aBlock

	"Answer a new parser that works on the receiving sequence an passes in each element as a block argument."

	^ aBlock numArgs = 1

		ifTrue: [ self ==> aBlock ]

		ifFalse: [ self error: aBlock numArgs asString , ' arguments expected.' ]

!

trim: aParser

	"Answer a new parser that consumes and ignores aParser repeatedly before and after the receiving parser."

	^ PPTrimmingParser on: self trimmer: aParser

!

trimBlanks

	"Answer a new parser that consumes blanks before and after the receiving parser."

	^ self trim: #blank asParser

!

trimLeft

	"Answer a new parser that consumes spaces before the receiving parser."

	^ self trimSpacesLeft

!

trimRight

	"Answer a new parser that consumes spaces after the receiving parser."

	^ self trimSpacesRight

!

trimSpaces

	"Answer a new parser that consumes spaces before and after the receiving parser."

	^ self trim: #space asParser

!

trimSpacesLeft

	"Answer a new parser that consumes spaces before the receiving parser."

	^ (#space asParser star, self) ==> #second

!

trimSpacesRight

	"Answer a new parser that consumes spaces after the receiving parser."

	^ (self, #space asParser star) ==> #first

! !

!PPParser methodsFor:'operators-repeating'!

max: anInteger

	"Answer a new parser that parses the receiver at most anInteger times."

	^ self star setMax: anInteger

!

max: anInteger greedy: aParser

	"Answer a new parser that parses the receiver at most anInteger times until it reaches aParser. This is a greedy non-blind implementation. aParser is not consumed."

	^ (self starGreedy: aParser) setMax: anInteger

!

max: anInteger lazy: aParser

	"Answer a new parser that parses the receiver at most anInteger times until it reaches aParser. This is a lazy non-blind implementation. aParser is not consumed."

	^ (self starLazy: aParser) setMax: anInteger

!

min: anInteger

	"Answer a new parser that parses the receiver at least anInteger times."

	^ self star setMin: anInteger

!

min: anInteger greedy: aParser

	"Answer a new parser that parses the receiver at least anInteger times until it reaches aParser. This is a greedy non-blind implementation. aParser is not consumed."

	^ (self starGreedy: aParser) setMin: anInteger

!

min: anInteger lazy: aParser

	"Answer a new parser that parses the receiver at least anInteger times until it reaches aParser. This is a lazy non-blind implementation. aParser is not consumed."

	^ (self starLazy: aParser) setMin: anInteger

!

min: aMinInteger max: aMaxInteger

	"Answer a new parser that parses the receiver at least aMinInteger and at most aMaxInteger times."

	^ self star setMin: aMinInteger; setMax: aMaxInteger

!

min: aMinInteger max: aMaxInteger greedy: aParser

	"Answer a new parser that parses the receiver at least aMinInteger and at most aMaxInteger times until it reaches aParser. This is a greedy non-blind implementation. aParser is not consumed."

	^ (self starGreedy: aParser) setMin: aMinInteger; setMax: aMaxInteger

!

min: aMinInteger max: aMaxInteger lazy: aParser

	"Answer a new parser that parses the receiver at least aMinInteger and at most aMaxInteger times until it reaches aParser. This is a greedy non-blind implementation. aParser is not consumed."

	^ (self starLazy: aParser) setMin: aMinInteger; setMax: aMaxInteger

!

plus

	"Answer a new parser that parses the receiver one or more times."

	^ self star setMin: 1

!

plusGreedy: aParser

	"Answer a new parser that parses the receiver one or more times until it reaches aParser. This is a greedy non-blind implementation of the star operator. aParser is not consumed."

	^ (self starGreedy: aParser) setMin: 1

!

plusLazy: aParser

	"Answer a new parser that parses the receiver one or more times until it reaches aParser. This is a lazy non-blind implementation of the star operator. aParser is not consumed."

	^ (self starLazy: aParser) setMin: 1

!

star

	"Answer a new parser that parses the receiver zero or more times. This is a greedy and blind implementation that tries to consume as much input as possible and it does not consider what comes afterwards."

	^ PPPossessiveRepeatingParser on: self

!

starGreedy: aParser

	"Answer a new parser that parses the receiver zero or more times until it reaches aParser. This is a greedy non-blind implementation of the star operator. aParser is not consumed."