orc.env
Class Env<T>

java.lang.Object
  orc.env.Env<T>

All Implemented Interfaces:

java.io.Serializable

public class Env<T>
extends java.lang.Object
implements java.io.Serializable

Generic indexed environment, used primarily at runtime. Env is also content addressable, so it can be used for the deBruijn index conversion in the compiler.

Author:

dkitchin

See Also:

Serialized Form

Nested Class Summary

protected class

Env.ENode Individual entries in the environment.

Constructor Summary

	Env()
protected	Env(Env.ENode node)

Method Summary

Env<T>	add(T item)
Env<T>	addAll(java.util.List<T> items)
T	lookup(int index) Lookup a variable in the environment Currently uses a linear search.
int	search(T target) Content addressable mode.
Env<T>	unwind(int width)

Methods inherited from class java.lang.Object

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

Constructor Detail

Env

protected Env(Env.ENode node)

Env

public Env()

Method Detail

add

public Env<T> add(T item)

addAll

public Env<T> addAll(java.util.List<T> items)

lookup

public T lookup(int index)

Lookup a variable in the environment Currently uses a linear search.

Parameters:

index - Stack depth (a deBruijn index)

Returns:

The bound item

search

public int search(T target)

Content addressable mode. Used in compilation to determine the deBruijn indices from an environment populated by Var objects. Assuming no error is raised, search and lookup are inverses: search(lookup(i)) = i lookup(search(o)) = o

Parameters:

target - The item

Returns:

The index of the target item

unwind

public Env<T> unwind(int width)