slogo.instruction

Class Backward

java.lang.Object

slogo.GrammarElement

slogo.instruction.Instruction

slogo.instruction.Backward

public class Backward
extends Instruction

Moves the turtle backwards by the amount specified

Field Summary

Fields

Modifier and Type	Field and Description
private GrammarElement	distance

Fields inherited from class slogo.GrammarElement

gelementsToValue

Constructor Summary

Constructors

Constructor and Description
Backward(GrammarElement e) Represents a backward instruction

Method Summary

Modifier and Type	Method and Description
java.lang.Object	evaluate(Context c) Evaluate this language construct in some context.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

distance

private GrammarElement distance

Constructor Detail

Backward

public Backward(GrammarElement e)

Represents a backward instruction

Parameters:

e - the expression to negate

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

the String representation of BACKWARD dist

evaluate

public java.lang.Object evaluate(Context c)

Description copied from class: GrammarElement

Evaluate this language construct in some context. The evaluation may have side-effects, e.g., moving a turtle.

Specified by:

evaluate in class Instruction

Parameters:

c - is the Context of what we are evaluating

Returns:

the position of the turtle as a point after moving the location