"

 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.

"

"{ Package: 'stx:libcomp' }"

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 helpers'!

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

    "/ let expression decide how to do it efficiently.

    expression

        codeForSimpleReturnOn:aStream 

        inBlock:b 

        lineNumber:lineNrOrNil 

        for:aCompiler

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

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

! !

!ReturnNode methodsFor:'accessing'!

expression:e

    super expression:e.

    "/ any block, which is returned cannot be inlined.

    e isBlockNode ifTrue:[

        e possiblyInlined:false

    ]

!

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:[

        self codeLineNumber:lineNr on:aStream for:aCompiler

    ].

    aStream nextPut:#homeRetTop.

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

! !

!ReturnNode methodsFor:'enumerating'!

nodeDo:anEnumerator

    "helper for parse tree walking"

    ^ anEnumerator doReturn:self value:expression

    "Modified: 19.6.1997 / 16:42:40 / cg"

! !

!ReturnNode methodsFor:'evaluation'!

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 & storing'!

printOn:aStream indent:i

    aStream nextPutAll:'^ '.

    expression printOn:aStream

! !

!ReturnNode methodsFor:'queries'!

isConstant

    ^ false

!

isReturnNode

    ^ true

! !

!ReturnNode class methodsFor:'documentation'!

version

    ^ '$Header: /cvs/stx/stx/libcomp/ReturnNode.st,v 1.26 2000-11-21 20:22:32 cg Exp $'

! !