polyglot.visit
Class FlattenVisitor

java.lang.Object
  extended by polyglot.visit.NodeVisitor
      extended by polyglot.visit.FlattenVisitor
All Implemented Interfaces:
java.lang.Cloneable, Copy

public class FlattenVisitor
extends NodeVisitor

The FlattenVisitor flattens the AST,


Field Summary
protected  java.util.Set neverFlatten
           
protected  NodeFactory nf
           
protected  java.util.Set noFlatten
           
protected  java.util.LinkedList stack
           
protected  TypeSystem ts
           
 
Constructor Summary
FlattenVisitor(TypeSystem ts, NodeFactory nf)
           
 
Method Summary
 NodeVisitor enter(Node parent, Node n)
          When entering a BlockStatement, place a new StatementList onto the stack
 Node leave(Node old, Node n, NodeVisitor v)
          Flatten complex expressions within the AST
protected static java.lang.String newID()
           
 Node override(Node parent, Node n)
          Given a tree rooted at n, the visitor has the option of overriding all traversal of the children of n.
 
Methods inherited from class polyglot.visit.NodeVisitor
begin, copy, enter, finish, finish, leave, override, toString, visitEdge, visitEdgeNoOverride
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

ts

protected TypeSystem ts

nf

protected NodeFactory nf

stack

protected java.util.LinkedList stack

noFlatten

protected java.util.Set noFlatten

neverFlatten

protected java.util.Set neverFlatten
Constructor Detail

FlattenVisitor

public FlattenVisitor(TypeSystem ts,
                      NodeFactory nf)
Method Detail

override

public Node override(Node parent,
                     Node n)
Description copied from class: NodeVisitor
Given a tree rooted at n, the visitor has the option of overriding all traversal of the children of n. If no changes were made to n and the visitor wishes to prevent further traversal of the tree, then it should return n. If changes were made to the subtree, then the visitor should return a copy of n with appropriate changes. Finally, if the visitor does not wish to override traversal of the subtree rooted at n, then it should return null.

The default implementation of this method is to call override(n), as most subclasses do not need to know the parent of the node n.

Overrides:
override in class NodeVisitor
Parameters:
parent - The parent of n, null if n has no parent.
n - The root of the subtree to be traversed.
Returns:
A node if normal traversal is to stop, null if it is to continue.

newID

protected static java.lang.String newID()

enter

public NodeVisitor enter(Node parent,
                         Node n)
When entering a BlockStatement, place a new StatementList onto the stack

Overrides:
enter in class NodeVisitor
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.

leave

public Node leave(Node old,
                  Node n,
                  NodeVisitor v)
Flatten complex expressions within the AST

Overrides:
leave in class NodeVisitor
Parameters:
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.