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

"{ NameSpace: Smalltalk }"

Object subclass:#PPCScannerCodeGenerator

	classVariableNames:''

	poolDictionaries:''

	category:'PetitCompiler-Scanner'

!

!PPCScannerCodeGenerator class methodsFor:'instance creation'!

new

    "return an initialized instance"

    ^ self basicNew initialize.

! !

!PPCScannerCodeGenerator methodsFor:'accessing'!

codeGen

    ^ codeGen 

!

compiler

    ^ self codeGen 

! !

!PPCScannerCodeGenerator methodsFor:'analysis'!

analyzeDistinctRetvals

    (fsa hasNoRetvals) ifTrue: [

        ^ resultStrategy := PPCNoResultStrategy new

            codeGen: codeGen;

            yourself

    ].

    (fsa hasDistinctRetvals) ifTrue: [

        ^ resultStrategy := PPCDistinctResultStrategy new

            codeGen: codeGen;

            yourself

    ].

    resultStrategy := PPCUniversalResultStrategy new

        codeGen: codeGen;

        tokens: fsa retvals asArray;

        yourself

!

analyzeTransitions

    | transitions |

    transitions := fsa allTransitions.

    incommingTransitions := IdentityDictionary new.

    (self incommingTransitionsFor: fsa startState) add: #transitionStub.

    transitions do: [ :t |

        (self incommingTransitionsFor: t destination) add: t.

    ].

!

clazz: aPPCClass

    codeGen clazz: aPPCClass

!

containsBacklink: state

    state transitions do: [ :t |

        (self isBacklink:  t) ifTrue: [ ^ true ]

    ].

    ^ false

!

hasMultipleIncommings: state

    ^ (incommingTransitions at: state ifAbsent: [ self error: 'should not happen']) size > 1

!

incommingTransitionsFor: state

    ^ incommingTransitions  at: state ifAbsentPut: [ IdentitySet new ]

!

isSingleTerminatingRetval: state

    (state retvals size == 1 and: [ state isFinal ]) ifFalse: [ ^ false ].

    state transitions isEmpty ifTrue: [ ^ true ].

    ((state transitions size == 1) and: [state destination == state]) ifTrue: [ ^ self startsSimpleLoop: state ].

    ^ false

!

isSingleTransitionFsa

    fsa allTransitions size == 1 ifFalse: [ ^ false ].

    "do not allow loop!!"

    fsa startState destination == fsa startState ifTrue: [ ^ false ].

    "so far only single char allowed"

    fsa startState transition isCharacterTransition ifFalse: [ ^ false ].

    fsa startState transition isSingleCharacter ifFalse: [ ^ false ].

    ^ true

!

startsSimpleLoop: state

    |   |

    "

        This accepts more or less something like $a star

        for now.. might extend later

    "

    ((self incommingTransitionsFor: state) size == 2) ifFalse: [ ^ false ].

    ^ (state transitions select: [ :t | t destination == state ]) size == 1

! !

!PPCScannerCodeGenerator methodsFor:'caching'!

cache: anFsa method: method

    ^ fsaCache at: anFsa put: method

!

cachedValueForIsomorphicFsa: anFsa

    | key |

    key := fsaCache keys detect: [ :e | e isIsomorphicTo: anFsa ].

    ^ fsaCache at: key

!

isomorphicIsCached: anFsa

    ^ fsaCache keys anySatisfy: [ :e | (e isIsomorphicTo: anFsa) and: [ e name = anFsa name ] ]

! !

!PPCScannerCodeGenerator methodsFor:'code generation'!

generate

    self assert: fsa isDeterministic.

    self assert: fsa isWithoutEpsilons.

    self assert: fsa checkConsistency.

    (self isomorphicIsCached: fsa) ifTrue: [ 

        "JK: please not, right now, checks for isomorphism and name

            this might be improved in future and name can be 'reused'

        "

        ^ self cachedValueForIsomorphicFsa: fsa 

    ].

    self analyzeTransitions.

    self analyzeDistinctRetvals.

    codeGen startMethod: (codeGen idFor: fsa).

"	codeGen codeComment: (Character codePoint: 13) asString, fsa asString."

    resultStrategy reset.

    self generateFor: fsa startState.

    ^ self cache: fsa method: codeGen stopMethod.

!

generate: aPEGFsa

    fsa := aPEGFsa.

    self assert: fsa isDeterministic.

    self assert: fsa isWithoutPriorities.

    fsa minimize.

    fsa checkSanity.

    ^ self generate

!

generateAndCompile

    self generate.

    ^ self compile

!

generateAndCompile: aPEGFsa

    fsa := aPEGFsa.

    fsa minimize.

    fsa checkSanity.

    ^ self generateAndCompile

!

generateFinalFor: state

    ^ self generateFinalFor: state offset: 0

!

generateFinalFor: state offset: offset

    "Handle one retval specially"

    (self isSingleTerminatingRetval: state) ifTrue: [  

        state isFsaFailure ifTrue: [ 

            resultStrategy returnFailure: state retval offset: offset.

        ] ifFalse: [ 

            resultStrategy returnMatch: state retval offset: offset.

        ].

        ^ self

    ].

    state retvalsAndInfosDo: [:retval :info |

        info isFinal ifTrue: [ 

            info isFsaFailure ifTrue: [ 

                resultStrategy recordFailure: retval offset: offset

            ] ifFalse: [ 

                resultStrategy recordMatch: retval offset: offset

            ]

        ].

    ]

!

generateFor: state

    codeGen cachedMethod: (codeGen idFor: state) ifPresent: [ :method | 

        "if state is already cached, it has multiple incomming links.

     	 In such a case, it is compiled as a method, thus return immediatelly"

        ^ codeGen codeAbsoluteReturn:  method call

    ].

    self flag: 'TODO JK: Hack alert, fix this:'.

    (state isKindOf: PEGFsaParserState) ifTrue: [ 

        | id |

        self assert: state transitions isEmpty.

        id := codeGen idFor: state parser defaultName: 'parser'.

        codeGen addConstant: state parser as: id.

        codeGen code: id, ' parseOn: context'.

        ^ self

    ].

    (self isSingleTransitionFsa) ifTrue: [ 

        ^ self generateForSingleTransitionFsa: state.

    ].

    (self startsSimpleLoop: state) ifTrue: [ 

        ^ self generateSimpleLoopFor: state

    ].

    ^ self generateStandardFor: state

!

generateForSingleTransitionFsa: startState

    | transition |

    self assert: fsa startState == startState.

    transition := startState transition.

    transition isSingleCharacter ifTrue: [ 

        codeGen codeIf: 'context peek == ', transition character storeString then: [ 

            codeGen code: 'self step'; codeDot.

            self generateFinalFor: transition destination.

        ]. 

        codeGen codeReturn: 'false'.

    ] ifFalse: [ 

        self error: 'should be implemented'

    ]

!

generateForTransition: t from: state		

"   

    (self isBacklink: t) ifTrue: [ 

        codeGen codeAssertPeek: (t characterSet) ifTrue: [ 

            codeGen add: 'true'

        ]

    ] ifFalse: [ 

        codeGen codeAssertPeek: (t characterSet) ifTrue: [

            self generateFor: t destination.

        ].

    ].

"

    codeGen codeAssertPeek: t ifTrue: [

        self generateFor: t destination.

    ].

    codeGen codeIfFalse.

!

generateNextFor: state

    state transitions isEmpty ifTrue: [  ^ self ].

    codeGen codeNextChar.

!

generateReturnFor: state

"	codeGen codeNl."

    (self isSingleTerminatingRetval: state) ifFalse: [ 

        resultStrategy returnResult: state.

    ] ifTrue: [ 

 		"return already generated within the match"	

    ]

!

generateSimpleLoopFor: state

    | selfTransition |

    selfTransition := state transitions detect: [ :t | t destination == state ].

    codeGen codeStartBlock.

    codeGen codeNextChar.

    codeGen codeNl.

    codeGen codeAssertPeek: selfTransition.

    codeGen codeEndBlockWhileTrue.

    "Last transition did not passed the loop, therefore, we have to record succes with offset -1"

    self generateFinalFor: state offset: 1.

    self generateTransitions: (state transitions reject: [ :t | t == selfTransition  ]) 

            for: state 

            offset: 1.

!

generateStandardFor: state

    self generateStartMethod: state.

    self generateFinalFor: state.

    self generateNextFor: state.

    self generateTransitionsFor: state.

    self generateStopMethod: state.

!

generateStartMethod: state

    | id |

    id := codeGen idFor: state.

    codeGen codeComment: 'START - Generated from state: ', state asString.

    (self hasMultipleIncommings: state) ifTrue: [ 

        codeGen startMethod: id.

    ] ifFalse: [ 

        codeGen  startInline: id.

    ]

!

generateStopMethod: state

    |  |

    (self hasMultipleIncommings: state) ifTrue: [ 

        codeGen codeAbsoluteReturn: codeGen stopMethod call.

    ] ifFalse: [ 

        codeGen code: codeGen stopInline call.

    ].

    codeGen codeComment: 'STOP - Generated from state: ', state asString.

!

generateTransitions: transitions for: state offset: offset

    (transitions size = 0) ifTrue: [  

        (offset > 0 and: [ state isFinal not ]) ifTrue:  [ 

            codeGen codeIf: 'currentChar isNil' then: nil else: [ 

                codeGen codeOnLine: 'context skip: -', offset asString 

            ].

        ].

        ^ self	

    ].

"	codeGen codeNl.

"	transitions do: [ :t |

        self generateForTransition: t from: state

    ].

    codeGen indent.

    self generateReturnFor: state.

    codeGen dedent.

    codeGen codeNl.

    transitions size timesRepeat: [ codeGen codeOnLine: ']' ].

    codeGen codeDot.

"	self closedJoinPoints isEmpty ifFalse: [ 

        | jp |

        self assert: self closedJoinPoints size == 1.

        jp := self closedJoinPoints anyOne.

        self removeJoinPoint: jp.

        self generateFor: jp.

    ]

"

!

generateTransitionsFor: state

    ^ self generateTransitions: state transitions for: state offset: 0

!

setMaxNumericId

    codeGen addConstant: codeGen idGen numericIds size as: #MaxSymbolNumber 

!

setTokens

    | tokens |

    tokens := Array new: codeGen idGen numericIdCache size.

    codeGen idGen numericIdCache keysAndValuesDo: [ :key :value |

        tokens at: value put: key

    ].

    codeGen addConstant: tokens as: #Tokens 

! !

!PPCScannerCodeGenerator methodsFor:'compiling'!

compile

    ^ self compileScannerClass new

!

compileScannerClass

    | builder |

    self setMaxNumericId.

    self setTokens.

    builder := PPCClassBuilder new.

    builder methodDictionary: codeGen clazz methodDictionary.

    builder constants: codeGen clazz constants.

    ^ builder compileClass.	

! !

!PPCScannerCodeGenerator methodsFor:'initialization'!

initialize

    super initialize.

    codeGen := PPCFSACodeGen new.

    fsaCache := IdentityDictionary new.

! !