slogo.instruction

Class PenDown

java.lang.Object

slogo.GrammarElement

slogo.instruction.Instruction

slogo.instruction.PenDown

public class PenDown
extends Instruction

A PENDOWN instruction has no components: when called, it puts the pen down, which gives the turtle drawing functionality. To evaluate a PENDOWN instruction, the setPenDown method is called on the turtle.

The value returned by evaluating a PENDOWN instruction is the expression itself.

Field Summary

Fields inherited from class slogo.GrammarElement

gelementsToValue

Constructor Summary

Constructors

Constructor and Description
PenDown()

Method Summary

Modifier and Type	Method and Description
java.lang.Object	evaluate(Context c) Evaluate this instruction in a Context.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

PenDown

public PenDown()

Method Detail

evaluate

public java.lang.Object evaluate(Context c)

Evaluate this instruction in a Context.

Specified by:

evaluate in class Instruction

Parameters:

c - the Context for the evaluation

Returns:

null

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

a String representing this instruction as PENDOWN