"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      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.

"

StatementNode subclass:#ReturnNode

	instanceVariableNames:'myHome blockHome'

	classVariableNames:''

	poolDictionaries:''

	category:'System-Compiler-Support'

!

!ReturnNode class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 by Claus Gittinger

	      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.

"

!

documentation

"

    node for parse-trees, representing return expressions

    This is a helper class for the compiler.

    [author:]

        Claus Gittinger

"

! !

!ReturnNode class methodsFor:'code generation helper'!

codeSimpleReturnFor:expression inBlock:b on:aStream inLine:lineNrOrNil for:aCompiler

    |type value index code code2|

    expression isPrimary ifTrue:[

        type := expression type.

        (type == #Nil) ifTrue:[

            code := #retNil

        ] ifFalse:[

            (type == #True) ifTrue:[

                code := #retTrue

            ] ifFalse:[

                (type == #False) ifTrue:[

                    code := #retFalse

                ] ifFalse:[

                    (type == #Self) ifTrue:[

                        code := #retSelf

                    ] ifFalse:[

                        (type == #Integer) ifTrue:[

                            value := expression evaluate.

                            (value between: -128 and:127) ifTrue:[

                                (value == 0) ifTrue:[

                                    code := #ret0

                                ] ifFalse:[

                                    code := #retNum.

                                    code2 := value. 

                                ]

                            ]

                        ] ifFalse:[

                            (type == #InstanceVariable) ifTrue:[

                                index := expression index.

                                (index <= 8) ifTrue:[

                                    code := #( retInstVar1

                                               retInstVar2

                                               retInstVar3

                                               retInstVar4

                                               retInstVar5

                                               retInstVar6

                                               retInstVar7

                                               retInstVar8) at:index

                                ]

                            ] ifFalse:[

                                (type == #MethodVariable) ifTrue:[

                                    index := expression index.

                                    (index <= 6) ifTrue:[

                                        code := #( retMethodVar1

                                                   retMethodVar2

                                                   retMethodVar3

                                                   retMethodVar4

                                                   retMethodVar5

                                                   retMethodVar6) at:index

                                    ]

                                ] ifFalse:[

                                    (type == #MethodArg) ifTrue:[

                                        index := expression index.

                                        (index <= 2) ifTrue:[

                                            code := #(retMethodArg1

                                                      retMethodArg2) at:index

                                        ]

                                    ]

                                ]

                            ]

                        ]

                    ]

                ]

            ]

        ]

    ].

    code isNil ifTrue:[

        expression codeOn:aStream inBlock:b for:aCompiler.

        code := #retTop

    ].

    lineNrOrNil notNil ifTrue:[

        ParseNode codeLineNumber:lineNrOrNil on:aStream for:aCompiler

    ].

    aStream nextPut:code.

    code2 notNil ifTrue:[

        aStream nextPut:code2

    ].

    "Created: 21.10.1996 / 14:37:35 / cg"

    "Modified: 21.10.1996 / 14:43:11 / cg"

! !

!ReturnNode methodsFor:'accessing'!

home:someOne blockHome:aBlockNode

    myHome := someOne.

    blockHome := aBlockNode

! !

!ReturnNode methodsFor:'code generation'!

codeForSideEffectOn:aStream inBlock:b for:aCompiler

    "redefined - drop not needed since notreached"

    ^ self codeOn:aStream inBlock:b for:aCompiler

!

codeOn:aStream inBlock:b for:aCompiler

    b isNil ifTrue:[

        ^ self class

            codeSimpleReturnFor:expression 

            inBlock:nil 

            on:aStream 

            inLine:lineNr 

            for:aCompiler

    ].

    expression codeOn:aStream inBlock:b for:aCompiler.

    lineNr notNil ifTrue:[

        ParseNode codeLineNumber:lineNr on:aStream for:aCompiler

    ].

    aStream nextPut:#homeRetTop.

    "Modified: 21.10.1996 / 14:54:36 / cg"

! !

!ReturnNode methodsFor:'evaluating'!

evaluateExpression

    |val|

    val := expression evaluate.

    myHome exitWith:val.

    "when we arrive here, the parser context is already gone

     - try block-return"

    blockHome notNil ifTrue:[blockHome exitWith:val].

    "well - what else can be done"

    ^ val

! !

!ReturnNode methodsFor:'printing'!

printOn:aStream indent:i

    aStream nextPutAll:'^ '.

    expression printOn:aStream

! !

!ReturnNode methodsFor:'queries'!

isConstant

    ^ false

!

isReturnNode

    ^ true

! !

!ReturnNode class methodsFor:'documentation'!

version

! !