polyglot.visit
Class ContextVisitor

java.lang.Object
  polyglot.visit.NodeVisitor
      polyglot.visit.HaltingVisitor
          polyglot.visit.ErrorHandlingVisitor
              polyglot.visit.ContextVisitor

All Implemented Interfaces:

java.lang.Cloneable, Copy

Direct Known Subclasses:

AddMemberVisitor, AmbiguityRemover, AscriptionVisitor, ConstructorCallChecker, FwdReferenceChecker, TypeChecker

public class ContextVisitor
extends ErrorHandlingVisitor

A visitor which maintains a context throughout the visitor's pass. This is the base class of the disambiguation and type checking visitors. TODO: update this documentation. For a node n methods are called in this order:

 v.enter(n)
   v.enterScope(n);
     c' = n.enterScope(c)
   v' = copy(v) with c' for c
 n' = n.visitChildren(v')
 v.leave(n, n', v')
   v.addDecls(n')
     n.addDecls(c)
 

Field Summary

protected Context	context The current context of this visitor.
protected ContextVisitor	outer

Fields inherited from class polyglot.visit.ErrorHandlingVisitor

error, job, nf, ts

Constructor Summary

ContextVisitor(Job job, TypeSystem ts, NodeFactory nf)

Method Summary

protected void	addDecls(Node n) Imperatively update the context with declarations to be added after visiting the node.
NodeVisitor	begin() Part of the initialization done by begin() in an ErrorHandlingVisitor method is initializing the error-handling state.
Context	context() Returns the context for this visitor.
ContextVisitor	context(Context c) Returns a new ContextVisitor that is a copy of the current visitor, except with an updated context.
NodeVisitor	enter(Node parent, Node n) Begin normal traversal of a subtree rooted at n.
protected Context	enterScope(Node parent, Node n) Returns a new context based on the current context, the Node current being visited (parent), and the Node that is being entered (n).
Node	leave(Node parent, Node old, Node n, NodeVisitor v) This method is called after all of the children of n have been visited.
NodeVisitor	superEnter(Node parent, Node n)

Methods inherited from class polyglot.visit.ErrorHandlingVisitor

catchErrors, enterCall, enterCall, enterError, errorQueue, job, leaveCall, leaveCall, nodeFactory, typeSystem

Methods inherited from class polyglot.visit.HaltingVisitor

bypass, bypass, bypassChildren, copy, override, visitChildren

Methods inherited from class polyglot.visit.NodeVisitor

enter, finish, finish, leave, override, toString, visitEdge

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

outer

protected ContextVisitor outer

context

protected Context context

The current context of this visitor.

Constructor Detail

ContextVisitor

public ContextVisitor(Job job,
                      TypeSystem ts,
                      NodeFactory nf)

Method Detail

begin

public NodeVisitor begin()

Description copied from class: ErrorHandlingVisitor

Part of the initialization done by begin() in an ErrorHandlingVisitor method is initializing the error-handling state.

Overrides:

begin in class ErrorHandlingVisitor

Returns:

the NodeVisitor to traverse the ast with. If null is returned, the ast is not traversed.

context

public Context context()

Returns the context for this visitor.

Returns:

Returns the context that is currently in use by this visitor.

See Also:

Context

context

public ContextVisitor context(Context c)

Returns a new ContextVisitor that is a copy of the current visitor, except with an updated context.

Parameters:

c - The new context that is to be used.

Returns:

Returns a copy of this visitor with the new context c.

enterScope

protected Context enterScope(Node parent,
                             Node n)

Returns a new context based on the current context, the Node current being visited (parent), and the Node that is being entered (n). This new context is to be used for visiting n.

Returns:

The new context after entering Node n.

addDecls

protected void addDecls(Node n)

Imperatively update the context with declarations to be added after visiting the node.

enter

public NodeVisitor enter(Node parent,
                         Node n)

Description copied from class: ErrorHandlingVisitor

Begin normal traversal of a subtree rooted at n. This gives the visitor the option of changing internal state or returning a new visitor which will be used to visit the children of n. This method delegates all responsibility of functionality to the enterCall method, and handles and reports any exceptions generated by enterCall. In overriding this method, unless the class explicitly does not want to maintain any of the error handling aspects of this class, a call super.enter should be embedded within the method at the end.

Overrides:

enter in class ErrorHandlingVisitor

Parameters:

parent - The parent of n, null if n has no parent.

n - The root of the subtree to be traversed.

Returns:

The NodeVisitor which should be used to visit the children of n.

superEnter

public NodeVisitor superEnter(Node parent,
                              Node n)

leave

public Node leave(Node parent,
                  Node old,
                  Node n,
                  NodeVisitor v)

Description copied from class: ErrorHandlingVisitor

This method is called after all of the children of n have been visited. In this case, these children were visited by the visitor v. This is the last chance for the visitor to modify the tree rooted at n. This method will be called exactly the same number of times as entry is called. That is, for each node that is not overriden, enter and leave are each called exactly once.

Note that if old == n then the vistior should make a copy of n before modifying it. It should then return the modified copy. This method delegates all responsibility of functionality to the leaveCall method, and handles and reports any exceptions generated by leaveCall. In overriding this method, unless the class explicitly does not want to maintain any of the error handling aspects of this class, a call super.leave should be embedded within the method at the end.

Overrides:

leave in class ErrorHandlingVisitor

Parameters:

parent - The parent of old, null if old has no parent.

old - The original state of root of the current subtree.

n - The current state of the root of the current subtree.

v - The NodeVisitor object used to visit the children.

Returns:

The final result of the traversal of the tree rooted at n.