DEFINITION MODULE Gas;
FROM NumTypes IMPORT Real8;
FROM ScrnTypes IMPORT DisplayFrame;
FROM DateFunctions IMPORT Date;

PROCEDURE DeleteGasFromInv(InvNbr: ARRAY OF CHAR);
PROCEDURE CheckOutGas(CustID,OutInvoiceNbr,InvtryItem : ARRAY OF CHAR;
                      Quant : CARDINAL;InvDate : Date);
PROCEDURE CheckInGas(CustID,InInvoiceNbr,InvtryItem: ARRAY OF CHAR;
                     Quant : CARDINAL;InvDate : Date);
PROCEDURE GasAmountDue(CustID, InvtryItem : ARRAY OF CHAR;Quant : CARDINAL;
		        InvDate   : Date;
                    VAR AmountDue : Real8;
		    VAR Notes     : ARRAY OF CHAR);  (* filled in if late*)
		
PROCEDURE ListOutstanding(CustID : ARRAY OF CHAR);
PROCEDURE ListHistory(CustID : ARRAY OF CHAR;DF1 : DisplayFrame);		    		
END Gas.