! Teaching outline: enter the function in a Team Developer application.
! This is not a complete importable .apt application file.
Function: TryLineTotal
    Returns
        Boolean:
    Parameters
        Number: nQuantity
        Number: nUnitPrice
        Number: nDiscountPercent
        Receive Number: nTotal
    Actions
        Set nTotal = NUMBER_Null
        If nQuantity = NUMBER_Null OR nUnitPrice = NUMBER_Null OR nDiscountPercent = NUMBER_Null
            Return FALSE
        If nQuantity < 0 OR nUnitPrice < 0 OR nDiscountPercent < 0 OR nDiscountPercent > 100
            Return FALSE
        Set nTotal = nQuantity * nUnitPrice * (100 - nDiscountPercent) / 100
        Return TRUE