identifiernode.java

是有关解释器的.用JAVA编写.可以解释一般的JAVA程序.

class IdentifierNode extends EvaluatableNode 
{
	String vName;

	static IdentifierNode parserIndentifier(Environment env, Scanner s) throws ParserException, ScannerException 
	{		
		return new IdentifierNode(matchIdentifier(s));
	}
	IdentifierNode() 
	{
		vName = null;
	}
	IdentifierNode(String aIdentifier) 
	{
		vName = aIdentifier;
	}
	String format(int indent) 
	{
		return vName;
	}
	Value evaluate(Environment env) throws InterpreterException 
	{
		if(env.at(vName).isNotFound())
			ProgramNode.mTypeCheckError("Undefined Identifier " + vName);		
		return (Value)env.at(vName);		
	}	
}