jltools.visit
Class ConstantFolder

java.lang.Object
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  +--jltools.ast.NodeVisitor
        |
        +--jltools.visit.BaseVisitor
              |
              +--jltools.visit.ConstantFolder

public class ConstantFolder

extends BaseVisitor

Visitor which performs constant folding.

Fields inherited from class jltools.visit.BaseVisitor

job

Constructor Summary

ConstantFolder(Job job)

Method Summary

Node	leave(Node old, Node n, NodeVisitor v) This method is called after all of the children of n have been visited.
Node	override(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 jltools.visit.BaseVisitor

errorQueue, importTable, job, nodeFactory, parsedResolver, typeSystem

Methods inherited from class jltools.ast.NodeVisitor

enter, finish, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ConstantFolder

public ConstantFolder(Job job)

Method Detail

override

public Node override(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.

Overrides:

override in class NodeVisitor

Following copied from class: jltools.ast.NodeVisitor

Parameters:

n - The root of the subtree to be traversed.

Returns:

A node if normal traversal is to stop, null if it is to continue.

leave

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

Description copied from class: NodeVisitor

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.

Overrides:

leave in class NodeVisitor

Following copied from class: jltools.ast.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.