"

 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' }"

ParseNode subclass:#StatementNode

	instanceVariableNames:'expression nextStatement lineNr'

	classVariableNames:''

	poolDictionaries:''

	category:'System-Compiler-Support'

!

!StatementNode 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 statements

    This is a helper class for the compiler.

    [author:]

        Claus Gittinger

"

! !

!StatementNode class methodsFor:'instance creation'!

expression:e

    ^ (self basicNew) expression:e

! !

!StatementNode methodsFor:'accessing'!

expression

    ^ expression

!

expression:e

    expression := e

!

last

    "return the last statement in a list"

    |last this|

    "this could be done more elegant - but with lots of recursion"

    last := self.

    this := self.

    [this notNil] whileTrue:[

	last := this.

	this := this nextStatement

    ].

    ^ last

!

lineNumber

    "return lineNr"

    lineNr notNil ifTrue:[^ lineNr].

    expression notNil ifTrue:[ ^ expression lineNumber ].

    nextStatement notNil ifTrue:[^ nextStatement lineNumber].

    ^ nil

    "Created: / 14.5.1998 / 19:31:06 / cg"

!

lineNumber:something

    "set lineNr"

    lineNr := something.

    "Created: / 14.5.1998 / 19:31:11 / cg"

!

lineNumberOfFirstMessage

    |lno|

    lno := self lineNumber.

    self messagesDo:[:m | lno := lno min:(m lineNumber)].

    ^ lno

!

nextStatement

    ^ nextStatement

!

nextStatement:s

    nextStatement := s

! !

!StatementNode methodsFor:'code generation'!

codeAllForSideEffectOn:aStream inBlock:b for:aCompiler

    |thisStatement|

    thisStatement := self.

    [thisStatement notNil] whileTrue:[

        thisStatement codeForSideEffectOn:aStream inBlock:b for:aCompiler.

        thisStatement := thisStatement nextStatement

    ].

!

codeForSideEffectOn:aStream inBlock:b for:aCompiler

    "generate code for this statement - value not needed"

    expression notNil ifTrue:[

        expression codeForSideEffectOn:aStream inBlock:b for:aCompiler

    ]

!

codeOn:aStream inBlock:b for:aCompiler

    "generate code for this statement"

    expression notNil ifTrue:[

        expression codeOn:aStream inBlock:b for:aCompiler

    ]

! !

!StatementNode methodsFor:'converting'!

asCollectionOfStatements

    "returns a orderedCollection of statements,

     representing the list of which the receiver is the head"

    |coll stat|

    coll := OrderedCollection new.

    stat := self.

    [stat notNil] whileTrue:[

        coll add:stat.

        stat := stat nextStatement.

    ].

    ^ coll

! !

!StatementNode methodsFor:'enumerating'!

messagesDo:aBlock

    |s e|

    s := self.

    [s notNil] whileTrue:[

        e := s expression.

        e notNil ifTrue:[e messagesDo:aBlock].

        s := s nextStatement

    ].

!

nodeDo:anEnumerator

    "helper for parse tree walking"

    "/ too stupid: ST/X statements are linked as a list ...

    stats := OrderedCollection new.

    this := self.

    [this notNil] whileTrue:[

        this := this nextStatement

    ].

    ^ anEnumerator doSequence:self temporaries:#() statements:stats

    "Created: 19.6.1997 / 16:45:34 / cg"

    "Modified: 19.6.1997 / 17:06:47 / cg"

! !

!StatementNode methodsFor:'evaluation'!

evaluateAllIn:anEnvironment

    |lastValue thisStatement|

    "this could be done more elegant - but with lots of recursion"

    thisStatement := self.

    [thisStatement notNil] whileTrue:[

        lastValue := thisStatement evaluateExpressionIn:anEnvironment.

        thisStatement := thisStatement nextStatement

    ].

    ^ lastValue

!

evaluateExpressionIn:anEnvironment

    ^ expression evaluateIn:anEnvironment

!

evaluateIn:anEnvironment

    ^ self evaluateAllIn:anEnvironment.

! !

!StatementNode methodsFor:'printing & storing'!

printAllOn:aStream 

    self printAllOn:aStream indent:4

!

printAllOn:aStream indent:i

    |thisStatement|

    thisStatement := self.

    [thisStatement notNil] whileTrue:[

        aStream spaces:i.

        thisStatement printOn:aStream indent:i.

        thisStatement nextStatement notNil ifTrue:[

            aStream cr.

        ].

        thisStatement := thisStatement nextStatement

    ]

!

printOn:aStream indent:i

    expression printOn:aStream indent:i.

! !

!StatementNode methodsFor:'queries'!

collectBlocksInto:aCollection

    |this ex|

    this := self.

    [this notNil] whileTrue:[

        ex := this expression.

        ex notNil ifTrue:[

            ex collectBlocksInto:aCollection.

        ].

        this := this nextStatement

    ].

    "Created: 23.10.1996 / 15:44:13 / cg"

    "Modified: 20.4.1997 / 12:10:18 / cg"

!

isConstant

    nextStatement notNil ifTrue:[^ false].

    ^ expression isConstant

!

listEndsWithReturn

    |thisStatement lastStatement|

    thisStatement := self.

    [thisStatement notNil] whileTrue:[

        lastStatement := thisStatement.

        thisStatement := thisStatement nextStatement

    ].

    ^ lastStatement isReturnNode

    "Created: 19.8.1996 / 14:32:47 / cg"

! !

!StatementNode class methodsFor:'documentation'!

version

! !