PPCNodeVisitor subclass:#PPCTokenCodeGenerator

	instanceVariableNames:'compiler scannerGenerator fsaCache'

!PPCTokenCodeGenerator methodsFor:'accessing'!

arguments: args

    super arguments: args.

    scannerGenerator arguments: args

!

compiler

    ^ compiler

!

compiler: anObject

    compiler := anObject.

    scannerGenerator compiler idGen: compiler idGen.

! !

!PPCTokenCodeGenerator methodsFor:'code support'!

consumeWhitespace: node

    self assert: node isTokenNode.

    node isTrimmingTokenNode ifTrue: [ 

        compiler code: 'self consumeWhitespace.'

    ]

!

createTokenInsance: node id: idCode start: startVar end: endVar

    compiler codeTranscriptShow: 'current token type: ', idCode.

    compiler codeAssign: idCode, '.' to: 'currentTokenType'.

    compiler codeAssign: node tokenClass asString, ' on: (context collection) 

                                                            start: ', startVar, ' 

                                                            stop: ', endVar, '

                                                            value: nil.'

               to: 'currentTokenValue'.

!

scan: node start: startVar end: endVar

    node child hasName ifFalse: [ 

        node child name: node name

    ].

    compiler codeAssign: 'context position + 1.' to: startVar.

    compiler add: ((self generateScan: node child) callOn: 'scanner').

!

unorderedChoiceFromFollowSet: followSet

    | followFsas  |

    ^ fsaCache at: followSet ifAbsentPut: [ 

        followFsas := followSet collect: [ :followNode | 

                (followNode asFsa) 

                    name: (compiler idFor: followNode);

                    retval: (compiler idFor: followNode); 

                    yourself

        ].

        self unorderedChoiceFromFsas: followFsas.

    ]

unorderedChoiceFromFsas: fsas

    | result startState |

    result := PEGFsa new.

    startState := PEGFsaState new.

    result addState: startState.

    result startState: startState.

    fsas do: [ :fsa | 

        result adopt: fsa.

        result addTransitionFrom: startState to: fsa startState.

    ].

    result determinizeStandard.

    ^ result

! !

!PPCTokenCodeGenerator methodsFor:'compiling support'!

compileScanner

    ^ scannerGenerator compileScannerClass

!

retvalVar

    ^ compiler currentReturnVariable

!

startMethodForNode:node

    node isMarkedForInline ifTrue:[ 

        compiler startInline: (compiler idFor: node).

        compiler codeComment: 'BEGIN inlined code of ' , node printString.

        compiler indent.

    ] ifFalse:[ 

        compiler startMethod: (compiler idFor: node).

        compiler currentMethod category: 'generated - tokens'.

        compiler codeComment: 'GENERATED by ' , node printString.

        compiler allocateReturnVariable.

    ]

stopMethodForNode:aPPCNode

    ^ aPPCNode isMarkedForInline ifTrue:[ 

                compiler dedent.

                compiler add: '"END inlined code of ' , aPPCNode printString , '"'.

                compiler stopInline.

    ] ifFalse:[ 

                compiler stopMethod

    ].

! !

!PPCTokenCodeGenerator methodsFor:'initialization'!

initialize

    super initialize.

    scannerGenerator := PPCScannerCodeGenerator new.

    scannerGenerator arguments: arguments.

    "for the given set of nodes, remember the unordered choice fsa

        see `unorderedChoiceFromFollowSet:`

    "

    fsaCache := Dictionary new.

! !

!PPCTokenCodeGenerator methodsFor:'scanning'!

generateNextScan: node

    | epsilon followSet  anFsa |

    followSet := node followSetWithTokens.

    epsilon := followSet anySatisfy: [ :e | e acceptsEpsilon ].

    followSet := followSet reject: [ :e | e acceptsEpsilon ].

    epsilon ifTrue: [ followSet add: PPCEndOfFileNode instance ].

    anFsa := self unorderedChoiceFromFollowSet: followSet.

    anFsa name: 'nextToken_', (compiler idFor: node).

    node nextFsa: anFsa.

    ^ scannerGenerator generate: anFsa.

!

generateScan: node

    | anFsa |

    anFsa := node asFsa determinize.

    anFsa name: (compiler idFor: node).

    anFsa retval: (compiler idFor: node).

    ^ scannerGenerator generate: anFsa.

visitToken: tokenNode

    |  id  startVar endVar  numberId |

    self startMethodForNode: tokenNode.

    self assert: tokenNode isMarkedForInline not.

    endVar := compiler allocateTemporaryVariableNamed:  'end'.

    id := compiler idFor: tokenNode.

    numberId := compiler numberIdFor: id.

    compiler add: 'currentTokenType isNil ifFalse: [ ^ currentTokenType == ', id storeString, '].'.

"	compiler codeComment: 'number for: ', id storeString, ' is: ', numberId storeString.

    compiler codeIf: 'scanner match: ', numberId storeString then: [ 

        compiler codeAssign: '(scanner resultPosition: ', numberId storeString, ').' to: endVar.

        self createTokenInsance: tokenNode 

                id: id storeString 

                start: '(context position + 1)' 

                end: endVar.

        compiler code: 'context position: ', endVar, '.'.

        self consumeWhitespace: tokenNode.

        compiler codeReturn: 'true'.

    ].

    compiler codeIf: 'scanner backtracked not' then: [ 

        compiler codeReturn: 'false'.

    ].

    compiler codeComment: 'No match, no fail, scanner does not know about this...'.	

"

"	self scan: tokenNode start: startVar end: endVar."

    "	compiler add: 'self assert: scanner isSingleMatch.'."

"	compiler codeIf: 'scanner match ' then: ["

    tokenNode child hasName ifFalse: [ 

        tokenNode child name: tokenNode name

    compiler codeAssign: 'context position + 1.' to: startVar.

    compiler codeIf: [ compiler code: ((self generateScan: tokenNode child) callOn: 'scanner') ] then: [ 

        compiler add: 'context position: scanner resultPosition.'.

        compiler codeAssign: 'context position.' to: endVar.	

        self consumeWhitespace: tokenNode.

        self createTokenInsance: tokenNode id: id storeString start: startVar end: endVar.

        compiler codeReturn: 'true'.

    ] else: [ 

        compiler code: 'scanner backtrackDistinct.'.

        compiler code: 'context position: ', startVar, ' - 1.'. 

        compiler codeReturn: 'false'.

    ].

    ^ self stopMethodForNode: tokenNode

!

visitTokenConsumeNode: node

    | id   nextScan |

    self startMethodForNode: node.

    id := (compiler idFor: node child).

    compiler add: 'self ', id asString, ' ifTrue: ['.

        compiler indent.

        nextScan := self generateNextScan: node.

        node nextFsa hasDistinctRetvals ifTrue: [ 

            compiler codeAssign: 'currentTokenValue.' to: self retvalVar.

            compiler add: (nextScan callOn: 'scanner'), '.'.

            compiler codeIf: 'scanner match' then: [ 

            compiler add: 'context position: scanner resultPosition.'.

                self createTokenInsance: node child 

                        id: 'scanner result' 

                        start: 'scanner position + 1' 

                        end: 'scanner resultPosition'.

                self consumeWhitespace: node child.

                compiler codeReturn.

            ] else: [ 

                compiler codeComment: 'Looks like there is an error on its way...'.

                compiler code: 'context position: scanner position.'.

                compiler codeAssign: 'nil.' to: 'currentTokenType'.

                compiler codeReturn.

            ]

        ] ifFalse: [ 

            compiler codeAssign: 'nil.' to: 'currentTokenType'.

            compiler codeReturn: 'currentTokenValue'.

        ].

        compiler dedent.

    "Token not found"

    compiler add: '] ifFalse: ['.

        compiler indent.

        compiler codeError: id asString, ' expected'.

        compiler dedent.

    compiler add: '].'.

    ^ self stopMethodForNode: node

!

visitTokenNode: node

    ^ self visitToken: node

    self startMethodForNode:node.

    compiler add: '(context peek == ', node child character storeString, ') ifFalse: [ ^ false ].'.

    self createTokenInsance: node id: id storeString  start: 'context position' end: 'context position'.

    self consumeWhitespace: node.

    compiler codeReturn: 'true'.

    ^ self stopMethodForNode: node

    ^ self visitToken: node