FiveTech Software tech support forums

James,

thank you very much for this tip, how to use inheritance and subtyping, polymorphism or overriding. How easy OOP can be

... where you derivate or create objects. Usually you never touch the code in a class, you derivate a new class from a existing one, a process called inheritance and then add the new features to the new class This process have nothing to deal with the Clipper.lib. There is an introduction to FW OOP ...

I did think about using inheritance but then I either have to write code that is very non-standard (@ <row>, <col> MyGET ....) or else I largely shift the update issue to modifying FiveLinux.ch. For an occasionally called ...

... can and manually do the rest. It splits the code for a data object into multiple places which I don't really like. But that is the advatange of inheritance. If you need to slightly change the behavior of a class you can do so with very little code. Also, if a bug is found and fixed or a feature ...

... why we have chosen the architecture we have and what to expect from it. So far I am getting the impression that you believe in OOP, but not in inheritance, encapsulation, or polymorphism. So, I am still left with my original impression that you don't really understand OOP. Regards, James

... of the above data source classes, and in the real-world objects such as Patient. So the data source is independent of the business rules. Using inheritance, the table subclasses can be very small. Anther OOP principle is to move as much code as possible as far up the inheritance ladder as possible. ...

... GUI let alone both. So I am coding my objects pretty much by hand from scratch. Then as patterns occur the degree to which I harness the power of inheritance will increase. Regards Doug

Doug, >I do use inheritance, but somewhat less than you in that I use xDATAFILE via class properties rather than direct inheritance. I'm still confused. You said you had a patientList class but below you are just using an instance ...

Hi James Our techniques vary, but we are actually more similar than someone casually reading these posts might imagine. Yes I do use inheritance, but somewhat less than you in that I use xDATAFILE via class properties rather than direct inheritance. I don't currently use any form of generic ...

... in the table class but I fear it would slow it down when you are doing browses and reports. Is this how you are doing them? >Using classes and inheritance gives a range of advantages. True they can cut coding and solve problems of variable "life" (sorry - can't remember technical term) largely ...

... to me, be in flagrant contradiction of your own polymorphism mantra - what does oObject:load() do - load one or load a list? Using classes and inheritance gives a range of advantages. True they can cut coding and solve problems of variable "life" (sorry - can't remember technical term) largely ...

... convince you to do things my way, I just think you are making it more difficult than it should be. One of the greatest advantages of OOP is using inheritance to make things simpler, and I think that you are not fully understanding it. >I take your point about "scatter / gather" but please note ...

... OO as a mechanism but is distorting it slightly. A Patient isn't a Table or even a record. Pragmatically this may not matter if the more natural inheritance that may exist is not required and all the natural objects map easily to single tables but I believe this approach can break down. That's ...

... strings. Whilst it doesn't have to be in any particular class, putting it in TWindow class makes it available in all the FiveLinux gui classes via inheritance. Regards Doug (xProgrammer)

... had a second thought on the above. What if we made it a method of class TWindow. Then it could be called from any of the FiveLinux gui classes by inheritance, couldn't it. That way it could be changed during execution if desired. A single call to the opening TWindow or TDialog object should suffice ...