public OperatorNode(NodeOperatorType opType, uint childNum)
 {
     _operatorType = opType;
     _childNum     = childNum;
     _children     = new NodeContainer();
 }
 public VariableNode(NodeVariableType varType)
 {
     _variableType = varType;
     _childNum     = 0;
     _children     = new NodeContainer();
 }
 public MultipleNode(float value)
 {
     _value    = value;
     _childNum = 1;
     _children = new NodeContainer();
 }
 public ConstNode(float value)
 {
     _value    = value;
     _childNum = 0;
     _children = new NodeContainer();
 }