usermessagenode.java

是有关解释器的.用JAVA编写.可以解释一般的JAVA程序.

class UserMessageNode extends EvaluatableNode
{
	IdentifierNode vIdentifierNode;
	ArgumentsNode vArgumentsNode;
	
	static UserMessageNode parserUserMessage(Environment env, Scanner s) throws ParserException, ScannerException
	{
		IdentifierNode tmpIdentifierNode;
		ArgumentsNode tmpArgumentsNode;
		
		tmpIdentifierNode= IdentifierNode.parserIndentifier(env,s);
		tmpArgumentsNode= ArgumentsNode.parserArguments(env,s);
		
		return new UserMessageNode(tmpIdentifierNode,tmpArgumentsNode);
	}
	UserMessageNode(IdentifierNode aIdentifierNode, ArgumentsNode aArgumentsNode)
	{
		vIdentifierNode= aIdentifierNode;
		vArgumentsNode= aArgumentsNode;
	}
	UserMessageNode()
	{
		vIdentifierNode= null;
		vArgumentsNode= null;
	}
	String format(int indent)
	{
		String str= vIdentifierNode.format(indent);
		if(vArgumentsNode!=null)return str+vArgumentsNode.format(indent)+"()";
			else return str+"()";
	}
	Value evaluate(Environment env) throws InterpreterException
	{
		MethodDefinitionNode tmpMethodDefinition= (MethodDefinitionNode)ProgramNode.vTopLevelEnvironment.get(vIdentifierNode.vName);
		FormalParametersNode tmpFormalParameters= tmpMethodDefinition.mGetForalParameters();
		Environment superEnvironment= new Environment();
		Environment vEnvironment= superEnvironment.mCreateNewEnvironment();
		
		superEnvironment.put(ProgramNode.vMessageReciever,env.get(ProgramNode.vMessageReciever));
		if(vArgumentsNode!=null)
			for(int i=0; i<vArgumentsNode.vArgumentsCount; i++)		
				vEnvironment.add(tmpFormalParameters.vVariableDeclarationNodes[i].mGetIdentifier(),vArgumentsNode.vExpressionNodes[i].evaluate(env));		
		ProgramNode.vTopLevelEnvironment.put("returnType", tmpMethodDefinition.mGetResultType());		
		if(tmpMethodDefinition.vBlockNode!=null)
			tmpMethodDefinition.vBlockNode.typeCheck(vEnvironment);
		tmpMethodDefinition.run(vEnvironment);	
		
		if(BlockNode.vReturn)
		{
			BlockNode.vReturn= false;
			return (Value)ProgramNode.vTopLevelEnvironment.at("returnValue");
		}			
		return null;
	}
	boolean typeCheck(Environment env) throws InterpreterException
	{				
		MethodDefinitionNode tmpMethodDefinition= (MethodDefinitionNode)ProgramNode.vTopLevelEnvironment.get(vIdentifierNode.vName);
		if(tmpMethodDefinition!=null)
		{
			FormalParametersNode tmpFormalParameters= tmpMethodDefinition.mGetForalParameters();								
			if(vArgumentsNode!=null)							
				if(vArgumentsNode.vArgumentsCount==tmpFormalParameters.vFormalParametersCount)					
					return vArgumentsNode.typeCheck(env);														
				else ProgramNode.mTypeCheckError(this.format(4));											
			else if(tmpFormalParameters.vFormalParametersCount!=0)ProgramNode.mTypeCheckError(this.format(4));		
		}else ProgramNode.mTypeCheckError(this.format(4));		
		
		return true;
	}
}