/// <summary>
 ///     Generates the node structure required to generate a default
 ///     initialization.
 /// </summary>
 /// <param name="p">
 ///     Tools.Parser instance to use when instantiating nodes.
 /// </param>
 /// <param name="constantType">String describing the datatype.</param>
 /// <returns>
 ///     A SYMBOL node conaining the appropriate structure for intializing a
 ///     constantType.
 /// </returns>
 private SYMBOL GetZeroConstant(Parser p, string constantType)
 {
     switch (constantType)
     {
         case "integer":
             return new Constant(p, constantType, "0");
         case "float":
             return new Constant(p, constantType, "0.0");
         case "string":
         case "key":
             return new Constant(p, constantType, "");
         case "list":
             ArgumentList al = new ArgumentList(p);
             return new ListConstant(p, al);
         case "vector":
             Constant vca = new Constant(p, "float", "0.0");
             Constant vcb = new Constant(p, "float", "0.0");
             Constant vcc = new Constant(p, "float", "0.0");
             ConstantExpression vcea = new ConstantExpression(p, vca);
             ConstantExpression vceb = new ConstantExpression(p, vcb);
             ConstantExpression vcec = new ConstantExpression(p, vcc);
             return new VectorConstant(p, vcea, vceb, vcec);
         case "rotation":
             Constant rca = new Constant(p, "float", "0.0");
             Constant rcb = new Constant(p, "float", "0.0");
             Constant rcc = new Constant(p, "float", "0.0");
             Constant rcd = new Constant(p, "float", "0.0");
             ConstantExpression rcea = new ConstantExpression(p, rca);
             ConstantExpression rceb = new ConstantExpression(p, rcb);
             ConstantExpression rcec = new ConstantExpression(p, rcc);
             ConstantExpression rced = new ConstantExpression(p, rcd);
             return new RotationConstant(p, rcea, rceb, rcec, rced);
         default:
             return null; // this will probably break stuff
     }
 }