polyglot.ext.pao.visit
Class PaoBoxer

java.lang.Object
  polyglot.visit.NodeVisitor
      polyglot.visit.HaltingVisitor
          polyglot.visit.ErrorHandlingVisitor
              polyglot.visit.ContextVisitor
                  polyglot.visit.AscriptionVisitor
                      polyglot.ext.pao.visit.PaoBoxer

All Implemented Interfaces:

java.lang.Cloneable, Copy

public class PaoBoxer
extends AscriptionVisitor

Visitor that inserts boxing and unboxing code into the AST. PaoBoxer accomplishes this task by first inserting explicit casts into the AST, where primitive values need to be treated as objects, and then uses the PaoExt.rewrite(PaoTypeSystem, NodeFactory) method to rewrite these explicit casts into appropriate boxing and unboxing code.

Field Summary

Fields inherited from class polyglot.visit.ContextVisitor

context

Fields inherited from class polyglot.visit.ErrorHandlingVisitor

error, job, nf, ts

Constructor Summary

PaoBoxer(Job job, TypeSystem ts, NodeFactory nf)

Method Summary

Expr	ascribe(Expr e, Type toType) Inserts an explicit cast if the type of expressions e is a primitive type, and the type toType is a reference type.
Node	leaveCall(Node old, Node n, NodeVisitor v) Calls the PaoExt.rewrite(PaoTypeSystem, NodeFactory) method to rewrite the explicit casts inserted by the ascribe method into correct boxing and unboxing code.

Methods inherited from class polyglot.visit.AscriptionVisitor

enterCall, pop, toType

Methods inherited from class polyglot.visit.ContextVisitor

addDecls, begin, context, context, enter, enterScope, leave, superEnter

Methods inherited from class polyglot.visit.ErrorHandlingVisitor

catchErrors, enterCall, enterError, errorQueue, job, 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

Constructor Detail

PaoBoxer

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

Method Detail

ascribe

public Expr ascribe(Expr e,
                    Type toType)

Inserts an explicit cast if the type of expressions e is a primitive type, and the type toType is a reference type. For example, Integer i = 42 will be modified to Integer i = (Object)42. The leaveCall method will ensure that these explicit casts are rewritten to the correct boxing and unboxing code.

Overrides:

ascribe in class AscriptionVisitor

Parameters:

e - The expression that is being visited

toType - The type that the parent node is expecting.

Returns:

The new translated Expr node, or if nothing has changed, just e.

leaveCall

public Node leaveCall(Node old,
                      Node n,
                      NodeVisitor v)
               throws SemanticException

Calls the PaoExt.rewrite(PaoTypeSystem, NodeFactory) method to rewrite the explicit casts inserted by the ascribe method into correct boxing and unboxing code.

Overrides:

leaveCall in class AscriptionVisitor

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.

Throws:

SemanticException

See Also:

NodeVisitor.leave(Node, Node, NodeVisitor)