"

              All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

MessageNode subclass:#UnaryNode

       instanceVariableNames:''

       classVariableNames:''

       poolDictionaries:''

       category:'System-Compiler-Support'

!

UnaryNode comment:'

              All Rights Reserved

'!

!UnaryNode class methodsFor:'instance creation'!

receiver:r selector:s

    ^ self receiver:r selector:s fold:true

!

receiver:r selector:s fold:folding

    |result recVal sym|

"

    The constant folding code can usually not optimize things - this may change

    when some kind of constant declaration is added to smalltalk.

"

    folding ifTrue:[

        "do constant folding ..."

        r isConstant ifTrue:[

            "check if we can do it ..."

            recVal := r evaluate.

            s knownAsSymbol ifTrue:[

                (recVal respondsTo:sym) ifTrue:[

                    "

                     we could do much more here - but then, we need a dependency from

                     the folded selectors method to the method we generate code for ...

                     limit optimizations to those that will never change 

                     (or, if you change them, it will crash badly anyway ...)

                    "

                    Number domainErrorSignal handle:[:ex |

                        ex return

                    ] do:[

                        sym := s asSymbol.

                        recVal respondsToArithmetic ifTrue:[

                            (#( negated abs asPoint degreesToRadians radiansToDegrees

                                exp ln log sqrt reciprocal 

                                arcCos arcSin arcTan sin cos tan) includes:sym)

                            ifTrue:[

                                result := recVal perform:sym.

                                ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                              value:result

                            ]

                        ].

                        (recVal isMemberOf:Character) ifTrue:[

                            (#( asciiValue asInteger digitValue) includes:sym) 

                            ifTrue:[

                                result := recVal perform:sym.

                                ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                              value:result

                            ]

                        ].

                        (recVal isMemberOf:String) ifTrue:[

                            (sym == #withCRs) ifTrue:[

                                result := recVal perform:sym.

                                ^ ConstantNode type:(ConstantNode typeOfConstant:result)

                                              value:result

                            ]

                        ].

                        ^ (self basicNew) receiver:r selector:s args:nil lineno:0

                    ].

                    "when we reach here, something went wrong (something like 0.0 log)"

                    ^ 'error occured when evaluating constant expression'

                ]

            ]

        ]

    ].

    ^ (self basicNew) receiver:r selector:s args:nil lineno:0

! !

!UnaryNode methodsFor:'queries'!

isUnaryMessage

    ^ true

! !

!UnaryNode methodsFor:'checks'!

plausibilityCheck

    "check for funny selector - careful to do string compare instead

     of symbol identity compare: I dont want to introduce these as symbols

     into the system (would make the '... is nowhere implemented' warning

     go away."

    ((selector = 'self') or:[

     (selector = 'super') or:[

     (Smalltalk includesKey:selector)]]) ifTrue:[

        ^ 'funny selector; possible missing ''.'' or keyword'

    ].

    "more to come ..."

    ^ nil

! !

!UnaryNode methodsFor:'evaluating'!

evaluate

    ^ (receiver evaluate) perform:selector

! !

!UnaryNode methodsFor:'code generation'!

codeOn:aStream inBlock:b

    "optimize 

        (a == b) not -> (a ~~ b)

        (a ~~ b) not -> (a == b)

    "

    (selector == #not) ifTrue:[

        (receiver class == BinaryNode) ifTrue:[

            (receiver selector == #==) ifTrue:[

                (BinaryNode receiver:(receiver receiver)

                            selector:#~~

                                 arg:(receiver arg)) codeOn:aStream inBlock:b.

                ^ self

            ].

            (receiver selector == #~~) ifTrue:[

                (BinaryNode receiver:(receiver receiver)

                            selector:#==

                                 arg:(receiver arg)) codeOn:aStream inBlock:b.

                ^ self

            ]

        ]

    ].

    ^ super codeOn:aStream inBlock:b

! !

!UnaryNode methodsFor:'printing'!

printOn:aStream indent:i

    |needParen|

    needParen := false.

    receiver isMessage ifTrue:[

        receiver isUnaryMessage ifFalse:[

            needParen := true

        ].

    ].

    needParen ifTrue:[

        aStream nextPutAll:'('

    ].

    receiver printOn:aStream.

    needParen ifTrue:[

        aStream nextPutAll:') '

    ].

    aStream space.

    selector printString printOn:aStream.

"    aStream space.     "

! !