slogo.instruction.drawing
Class Back

java.lang.Object
  extended by slogo.language.GrammarElement
      extended by slogo.instruction.Instruction
          extended by slogo.instruction.drawing.OneParameterInstruction
              extended by slogo.instruction.drawing.Back

public class Back
extends OneParameterInstruction

moves the turtle backwards by the amount specified

Author:
tshishikub

Field Summary
 
Fields inherited from class slogo.instruction.drawing.OneParameterInstruction
param
 
Fields inherited from class slogo.language.GrammarElement
gelementsToValue
 
Constructor Summary
Back(GrammarElement e)
           
 
Method Summary
 java.lang.Object evaluate(Context c)
          Evaluate this language construct in some context.
 
Methods inherited from class slogo.instruction.Instruction
evaluateNumericExpression
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

Back

public Back(GrammarElement e)
Method Detail

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 OneParameterInstruction
Parameters:
c - context in which the evaluation takes place
Returns:
the result of evaluating the construct