Danmaku_no_Kyojin.BulletEngine.Equationator.BaseNode.ParseValueNode C# (CSharp) Method

        protected static BaseNode ParseValueNode(List<Token> tokenList, ref int curIndex, Equation owner)
        {
            Debug.Assert(null != tokenList);
            Debug.Assert(null != owner);
            Debug.Assert(curIndex < tokenList.Count);

            //what kind of token do I have at that index?
            switch (tokenList[curIndex].TypeOfToken)
            {
                case TokenType.Number:
                {
                    //awesome, that's nice and easy... just shove the text into a node as a number

                    //create the number node
                    NumberNode valueNode = new NumberNode();

                    //parse the text into the number node
                    valueNode.ParseToken(tokenList, ref curIndex, owner);

                    //return the number node as our result
                    return valueNode;
                }

                case TokenType.Param:
                {
                    //also not bad, grab the text as a parameter index and put in a node

                    //create the param node
                    ParamNode valueNode = new ParamNode();

                    //parse the parameter index into the node
                    valueNode.ParseToken(tokenList, ref curIndex, owner);

                    //return it as our result
                    return valueNode;
                }

                case TokenType.Function:
                {
                    //hmmm... need to get the delegate and put in a node?

                    //create the function node
                    FunctionNode valueNode = new FunctionNode();

                    //parse the function delegate into the node
                    valueNode.ParseToken(tokenList, ref curIndex, owner);

                    //return it as our result
                    return valueNode;
                }

                case TokenType.OpenParen:
                {
                    //ok don't panic...

                    //verify that this is not the last token
                    if (curIndex >= (tokenList.Count - 1))
                    {
                        throw new FormatException("Can't end an equation with an open paranthesis");
                    }

                    //move past this token, cuz nothing else to do with it
                    curIndex++;

                    //starting at the next token, start an equation node
                    EquationNode valueNode = new EquationNode();

                    //start parsing into the equation node
                    valueNode.ParseToken(tokenList, ref curIndex, owner);

                    //return it as the result
                    return valueNode;
                }

                case TokenType.Operator:
                {
                    //whoa, how did an operator get in here?  it better be a minus sign
                    return EquationNode.ParseNegativeToken(tokenList, ref curIndex, owner);
                }

                default:
                {
                    //should just be close paren nodes in here, which we should never get
                    throw new FormatException("Expected a \"value\" token, but got a " + tokenList[curIndex].TypeOfToken.ToString());
                }
            }
        }

        /// <summary>
        /// This method gets called when the token parser encounters a minus sign in front of a value.
        /// If the next token is a number, it will be changed to a negative number.
        /// If the next token is a funcion, param, or equation, an equation will be generated that multiplies the result by -1
        /// </summary>
        /// <returns>The negative token.</returns>
        /// <param name="tokenList">Token list.</param>
        /// <param name="curIndex">Current index.</param>
        /// <param name="owner">Owner.</param>
        public static BaseNode ParseNegativeToken(List <Token> tokenList, ref int curIndex, Equation owner)
        {
            //verify that this is not the last token
            if (curIndex >= (tokenList.Count - 1))
            {
                throw new FormatException("Can't end an equation with an operator");
            }

            //check that the token is a minus sign
            if ("-" != tokenList[curIndex].TokenText)
            {
                throw new FormatException("Expected a value, but found an invalid operator instead");
            }

            //skip past the minus sign so we can get to the next token
            curIndex++;

            //create a number node, parse the next token into it
            BaseNode valueNode = BaseNode.ParseValueNode(tokenList, ref curIndex, owner);

            Debug.Assert(null != valueNode);

            //what did we get back?
            if (valueNode is NumberNode)
            {
                //the next node is a number, multiply it by minus one
                NumberNode myNumberNode = valueNode as NumberNode;
                myNumberNode.NumberValue *= -1.0f;
            }
            else
            {
                //ok the node was a function, param, or equation

                //create another equation to multiply that resdult by -1
                NumberNode negativeOne = new NumberNode();
                negativeOne.NumberValue = -1.0f;
                OperatorNode multiplyNode = new OperatorNode();
                multiplyNode.Operator = '*';

                //string it all together
                negativeOne.AppendNextNode(multiplyNode);
                multiplyNode.AppendNextNode(valueNode);

                //put that into an equation node and treeify it
                EquationNode myEquationNode = new EquationNode();
                myEquationNode.SubEquation = negativeOne.Treeify();
                Debug.Assert(null != myEquationNode.SubEquation);

                //set our result to the whole equation
                valueNode = myEquationNode;
            }

            //return it as the result
            return(valueNode);
        }