Class Conditional

java.lang.Object
  Conditional

All Implemented Interfaces:

Expression

public class Conditional
extends java.lang.Object
implements Expression

A Conditional is an if-then-else expression.

Constructor Summary

Conditional(Expression test, Expression ifTrue, Expression ifFalse)
Creates a Conditional with the specified components.

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

Conditional

public Conditional(Expression test,
                   Expression ifTrue,
                   Expression ifFalse)

Creates a Conditional with the specified components.

Parameters:

test - an expression which evaluates to true or false

ifTrue - the expression to evaluate if the test returns true

ifFalse - the expression to evaluate if the test returns false

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