Class Variable

java.lang.Object
  Variable

All Implemented Interfaces:

Expression

public class Variable
extends java.lang.Object
implements Expression

A Variable is a name used as an expression.

Constructor Summary

Variable(java.lang.String name)
Creates a Variable with the specified name.

Method Summary

java.lang.Object

eval(Environment env) Evaluate this expression.

Methods inherited from class java.lang.Object

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

Constructor Detail

Variable

public Variable(java.lang.String name)

Creates a Variable with the specified name.

Parameters:

name - the name for this variable

Method Detail

eval

public java.lang.Object eval(Environment env)

Description copied from interface: Expression

Evaluate this expression. When an Expression is evaluated, this must happen in some particular environment. For example, evaluating the variable x in one environment might produce a totally different value than evaluating it in another environment.

Specified by:

eval in interface Expression

Parameters:

env - the environment in which the expression should be evaluated

Returns:

the value produced by the expression