objectcreationnode.java

是有关解释器的.用JAVA编写.可以解释一般的JAVA程序.

class ObjectCreationNode extends EvaluatableNode
{
	ArgumentsNode vArgumentsNode;
	Value vStreetValue;
	Value vAvenueValue;
	Value vBeepersValue;
	Value vDirectionValue;
	
	static ObjectCreationNode parserObjectCreation(Environment env, Scanner s) throws ParserException, ScannerException
	{
		matchKeyword(s,"new");
		matchKeyword(s,"Robot");
		
		return new ObjectCreationNode(ArgumentsNode.parserArguments(env,s));
	}	
	static boolean mIsObjectCreation(Scanner s) throws ScannerException
	{
		return isKeywordToken(s,"new");
	}
	ObjectCreationNode(ArgumentsNode aArgumentsNode)
	{
		vArgumentsNode= aArgumentsNode;
	}
	ObjectCreationNode()
	{
		vArgumentsNode= null;
	}
	String format(int indent)
	{
		String str="new Robot";
		if(vArgumentsNode!=null)str+= vArgumentsNode.format(indent);
			else str+="()";
		return str;
	}
	Value evaluate(Environment env) throws InterpreterException
	{		
		int street= ((NumberValue)vStreetValue).numberValue();
		int avenue= ((NumberValue)vAvenueValue).numberValue();
		int beepers= ((NumberValue)vBeepersValue).numberValue();
		int direct= ((DirectionValue)vDirectionValue).numberValue();
		QueryRobot r=null;
		
		switch(direct)
		{
			case 0:
				r= new QueryRobot(street,avenue,beepers,direction.WEST);
				break;
			case 1:
				r= new QueryRobot(street,avenue,beepers,direction.SOUTH);
				break;
			case 2:
				r= new QueryRobot(street,avenue,beepers,direction.EAST);
				break;
			case 3:		
				r= new QueryRobot(street,avenue,beepers,direction.NORTH);
				break;
		}
				
		return new RobotValue(r);
	}
	boolean typeCheck(Environment env) throws InterpreterException
	{
		if(vArgumentsNode==null)ProgramNode.mTypeCheckError(this.format(4)+"\n Arguments: Street,Avenue,Beepers,Direction");
		if(vArgumentsNode.vArgumentsCount!=4)ProgramNode.mTypeCheckError(this.format(4)+"\n Arguments: Street,Avenue,Beepers,Direction");
		if(vArgumentsNode.typeCheck(env))
		{
			vStreetValue= vArgumentsNode.vExpressionNodes[0].evaluate(env);
			vAvenueValue= vArgumentsNode.vExpressionNodes[1].evaluate(env);
			vBeepersValue= vArgumentsNode.vExpressionNodes[2].evaluate(env);
			vDirectionValue= vArgumentsNode.vExpressionNodes[3].evaluate(env);
			if(vStreetValue.isNumber()&&vAvenueValue.isNumber()&&vBeepersValue.isNumber()&&vDirectionValue.isDirection())
				return true;
			else ProgramNode.mTypeCheckError(this.format(4)+"\n Arguments is wrong type");
		}else ProgramNode.mTypeCheckError(this.format(4)+"\n Arguments is wrong type");		
		
		return true;
	}
}