slogo.instruction

Class Subroutine

java.lang.Object

slogo.GrammarElement

slogo.instruction.Instruction

slogo.instruction.Subroutine

public class Subroutine
extends Instruction

An assignment instruction assigns an expression to a variable, updating the global state to reflect the assignment.

Executing the assignment instruction causes the expression to be evaluated and assigned to the variable, until the assignment instruction executes, the expression isn't evaluated.

Field Summary

Fields

Modifier and Type	Field and Description
protected StrictInstructionList	mySubroutineList
protected java.lang.String	mySubroutineName

Fields inherited from class slogo.GrammarElement

gelementsToValue, subroutineNames

Constructor Summary

Constructors

Constructor and Description
Subroutine(java.lang.String subroutineName) Construct an Assignment instruction from a variable and an expression, e.g., X = expression.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	evaluate(Context c) Evaluate the expression that's part of this instruction and update a global map/store to record the assignment of the expression to the variable.
java.lang.String	toString() Returns a String for this instruction.

Methods inherited from class java.lang.Object

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

Field Detail

mySubroutineName

protected java.lang.String mySubroutineName

mySubroutineList

protected StrictInstructionList mySubroutineList

Constructor Detail

Subroutine

public Subroutine(java.lang.String subroutineName)

Construct an Assignment instruction from a variable and an expression, e.g., X = expression.

Parameters:

e - expression being assigned

v - variable to which the expression is assigned

Method Detail

evaluate

public java.lang.Object evaluate(Context c)

Evaluate the expression that's part of this instruction and update a global map/store to record the assignment of the expression to the variable.

Specified by:

evaluate in class Instruction

Parameters:

c - is the Context in which the evaluation takes place

Returns:

the result of evaluation (which is the expression assigned)

toString

public java.lang.String toString()

Returns a String for this instruction.

Overrides:

toString in class java.lang.Object

Returns:

VAR = EXPRESSION