`TFPSubtractOperation`
		Check
		GetNodeValue
		AsString

`TMathOperation`
		Check
		NodeType

`TFPBinaryOperation`
pt		CheckSameNodeTypes
		Create
		Destroy
		InitAggregate
		UpdateAggregate
		HasAggregate
		Check

`TFPExprNode`
pt		CheckNodeType
pt		GetNodeValue
		Check
		InitAggregate
		UpdateAggregate
		IsAggregate
		HasAggregate
		NodeType
		NodeValue
		AsString