jsint
Class Environment

java.lang.Object
  |
  +--jsint.Environment

public class Environment

extends java.lang.Object

Environments store mappings from symbols to locations. At compile time, we can lookup to see if a symbol names a location, and at run time we can get or set the value in a location.

Author:

Peter Norvig, Copyright 1998, peter@norvig.com, license subsequently modified by Jscheme project members licensed under zlib licence (see license.txt)

Field Summary

static Environment

GLOBAL The global environment.

Constructor Summary

Environment(java.lang.Object vars, java.lang.Object[] vals, Environment parent)
Create an Environment with local variables and values, and a parent Environment.

Method Summary

java.lang.Object	get(LocalVariable var) Get the value of the LocalVariable in this Environment.
java.lang.Object	lookup(Symbol var)
java.lang.Object	lookup(Symbol var, int up, int in, java.lang.Object vars) Lookup the symbol in the environment.
java.lang.Object	set(LocalVariable var, java.lang.Object newVal) Set the value of the LocalVariable in this Environment to a new value.
void	show(java.io.PrintWriter s)
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

GLOBAL

public static final Environment GLOBAL

The global environment. All info is in the Symbols themselves.

Constructor Detail

Environment

public Environment(java.lang.Object vars,
                   java.lang.Object[] vals,
                   Environment parent)

Create an Environment with local variables and values, and a parent Environment.

Method Detail

lookup

public java.lang.Object lookup(Symbol var)

lookup

public java.lang.Object lookup(Symbol var,
                               int up,
                               int in,
                               java.lang.Object vars)

Lookup the symbol in the environment. Return either a LocalVariable a Symbol representing the global variable.

get

public java.lang.Object get(LocalVariable var)

Get the value of the LocalVariable in this Environment.

set

public java.lang.Object set(LocalVariable var,
                            java.lang.Object newVal)

Set the value of the LocalVariable in this Environment to a new value.

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

show

public void show(java.io.PrintWriter s)