slogo.instruction

Class SetXY

java.lang.Object

slogo.GrammarElement

slogo.instruction.Instruction

slogo.instruction.SetXY

public class SetXY
extends Instruction

A SETXY instruction has two components: two GrammarElements that represents the x and y coordinates to set. To evaluate a SETXY instruction the expressions are evaluated first, this determines the double version of the x and y coordinates. The turtle's coordinates are then reset and the turtle is moved to the new x and new y coordinates.

The value returned by evaluating a SETXY instruction is the instruction itself.

Field Summary

Fields

Modifier and Type	Field and Description
private GrammarElement	expressionOne
private GrammarElement	expressionTwo

Fields inherited from class slogo.GrammarElement

gelementsToValue

Constructor Summary

Constructors

Constructor and Description
SetXY(GrammarElement g, GrammarElement h) Constructs a SETXY instruction that can be executed.

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

Field Detail

expressionOne

private GrammarElement expressionOne

expressionTwo

private GrammarElement expressionTwo

Constructor Detail

SetXY

public SetXY(GrammarElement g,
             GrammarElement h)

Constructs a SETXY instruction that can be executed.

Parameters:

g - the new x coordinate

h - the new y coordinate

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:

string version of new point

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

Returns:

a String representing this instruction as SETXY