`TFPExprFunction`
pt		CalcParams
pt		ConvertArgument
		Check
		CreateFunction
		Destroy
		InitAggregate
		UpdateAggregate
		HasAggregate
		AsString

`TFPExprIdentifierNode`
		CreateIdentifier
		NodeType
		GetNodeValue

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