"{ Package: 'stx:libcomp' }"

"{ NameSpace: Smalltalk }"

ParseNodeVisitor subclass:#PluggableParseNodeVisitor
	instanceVariableNames:'actionsPerNodeType'
	classVariableNames:''
	poolDictionaries:''
	category:'System-Compiler-Support'
!

!PluggableParseNodeVisitor class methodsFor:'documentation'!

documentation
"
    a pluggable node visitor.
    setup with:
        actionForNodeClass:aClass put:aBlock
        
    for example, if you are only interested in assignments,
    use the following code:
        |v|
        v := PluggableParseNodeVisitor new.
        v actionForNodeClass:AssignmentNode put:[:node | Transcript showCR:node. true].
        v visit:(Parser parse:code in:someClass.
"
! !

!PluggableParseNodeVisitor methodsFor:'setup'!

actionForNodeClass:aNodeClass put:aBlock
    "setup so that for nodes of type aNodeClass, aBlock is invoked.
     If the block returns true, subnodes (eg. right side of assignments, etc.)
     will be enumerated as well.
     Otherwise, no subnodes are visited."

    actionsPerNodeType isNil ifTrue:[
         actionsPerNodeType := Dictionary new.
    ].
    actionsPerNodeType at:aNodeClass put:aBlock
! !

!PluggableParseNodeVisitor methodsFor:'visiting'!

visit:aNodeObject
    "redefined to look for an action for this node's class.
     If there is one, it can specify if subnodes are to be visited too"
     
    |action|

    action := actionsPerNodeType at:aNodeObject class ifAbsent:[nil].
    action notNil ifTrue:[ 
        (action value:aNodeObject) ifFalse:[^ self].
    ].
    super visit:aNodeObject
! !

!PluggableParseNodeVisitor class methodsFor:'documentation'!

version
    ^ '$Header$'
!

version_CVS
    ^ '$Header$'
! !