Re: RPG400-L Digest, Vol 6, Issue 1041

vern wrote:

1. Re: Need some advice (vhamberg)

I think we work in object-oriented ways more than we know. For one thing, consider the object-based design of the S/38 - AS/400 - iSeries - i5 and you will have some groundwork. E.g., a *FILE object could be considered a class - I know, it's deeper than that, but let's keep this simple - am just forming this on the fly - and a *FILE object has certain attributes at what we call file-level (file level identifier os one). ALL *FILE objects have these same attributes.

This seems very relevant to the discussion. The various commands -- CRTPGM, DLTPGM, CHGPGM, DSPPGM, DSPPGMREF -- "send messages" to the objects and receive results back.

Each such "message" is appropriate only to the class and subclass of the object, and often only to the specific "instance" of object.

The basics of OO are available to all of us for understanding. We just need to view what we do in the appropriate ways.

Tom Liotta

Now on the iSeries there are also methods contained in every object - things you can do - you can't write to a *PGM but you can to a *FILE.

Then you get a subclass, PF is one, DSPF is another, PRTF another. These all inherit the attributes and methods of the parent *FILE. Then each one adds attributes and methods and perhaps puts in a subclass-specific version of methods that are called first, maybe.

With PFs you can get further subclass of SQL table - and on it goes.

In our programming, as soon as you get into service programs and subprocedures, you are starting to talk about separating routines - you may even be setting up variables and using setters and getters for various things - you CAN do OO programming in any language, it's just easier in a language that supports it.