Edit file File name : visitor.pyc Content :� �bc @ s[ d d l m Z d d d � � YZ d e f d � � YZ e Z d d d � Z d � Z d S( i����( t astt ASTVisitorc B s8 e Z d Z d Z d � Z d � Z d � Z d � Z RS( s Performs a depth-first walk of the AST The ASTVisitor will walk the AST, performing either a preorder or postorder traversal depending on which method is called. methods: preorder(tree, visitor) postorder(tree, visitor) tree: an instance of ast.Node visitor: an instance with visitXXX methods The ASTVisitor is responsible for walking over the tree in the correct order. For each node, it checks the visitor argument for a method named 'visitNodeType' where NodeType is the name of the node's class, e.g. Class. If the method exists, it is called with the node as its sole argument. The visitor method for a particular node type can control how child nodes are visited during a preorder walk. (It can't control the order during a postorder walk, because it is called _after_ the walk has occurred.) The ASTVisitor modifies the visitor argument by adding a visit method to the visitor; this method can be used to visit a child node of arbitrary type. i c C s d | _ i | _ d S( N( t Nonet nodet _cache( t self( ( s& /usr/lib/python2.7/compiler/visitor.pyt __init__" s c G s+ x$ | j � D] } | j | | � q Wd S( N( t getChildNodest dispatch( R R t argst child( ( s& /usr/lib/python2.7/compiler/visitor.pyt default& s c G su | | _ | j } | j j | d � } | d k rh | j } t | j d | | j � } | | j | <n | | | � S( Nt visit( R t __class__R t getR t __name__t getattrt visitorR ( R R R t klasst metht className( ( s& /usr/lib/python2.7/compiler/visitor.pyR * s c G s) | | _ | j | _ | j | | � d S( s& Do preorder walk of tree using visitorN( R R R ( R t treeR R ( ( s& /usr/lib/python2.7/compiler/visitor.pyt preorder; s ( R t __module__t __doc__t VERBOSER R R R ( ( ( s& /usr/lib/python2.7/compiler/visitor.pyR s t ExampleASTVisitorc B s e Z d Z i Z d � Z RS( s� Prints examples of the nodes that aren't visited This visitor-driver is only useful for development, when it's helpful to develop a visitor incrementally, and get feedback on what you still have to do. c G sG | | _ | j j | j d � } | j j } | d k re t | j d | d � } | | j | j <n | j d k r� d G| G| r� | j p� d GHn | r� | | | � n� | j d k rC| j } | | j k r3| | j | <H| j GH| GHxA t | � D]3 } | d d k r� d Gd | Gt | | � GHq� q� WHn | j | | � Sd S( NR i i R t t _s s %-12.12s( R R R R R R R R R t examplest dirR ( R R R R R R t attr( ( s& /usr/lib/python2.7/compiler/visitor.pyR J s, !( R R R R R ( ( ( s& /usr/lib/python2.7/compiler/visitor.pyR A s c C sG | d k r t � } n | d k r0 | | _ n | j | | � | j S( N( R t _walkerR R R ( R R t walkert verbose( ( s& /usr/lib/python2.7/compiler/visitor.pyt walke s c C sP | j GHxA t | � D]3 } | d d k r d Gd | Gt | | � GHq q Wd S( Ni R s s %-10.10s( R R R ( R R ( ( s& /usr/lib/python2.7/compiler/visitor.pyt dumpNodem s N( ( t compilerR R R R R R# R$ ( ( ( s& /usr/lib/python2.7/compiler/visitor.pyt <module> s ;#Save