Re: Legacy code. -- MIDRANGE-L



>As far as VA RPG is concerned, I've never quite seen the justification
>for it, or ASNA's Visual RPG. It just seems they're neither fish nor
>fowl. You almost have to learn another language as a wrapper around the
>one you're already using, and you need to use both, not just the one.

I am not sure what you mean. There are a few new op codes with VA RPG, but
they are for events you do not need to watch for on a midrange.


>I've been looking at VA for Java lately, and it's very impressive. The
>design paradigm uses connections between the various elements, both
>graphical and not. Almost everything that you need for processing the
>front end gets built automatically. Most of what you need to code is the
>business logic only, once you've done that, your logic can be connected
>into the design, too.

I have been working with VA Java, and I love it. It is a wonderful new
environment that allows me to program applications that I can run on an
AS/400. I can test the programs here on my PC, store them on a diskette or
email them to myself and then run them on a 400.

I felt like VA RPG was a very similar experience. I must confess that I
enjoy working with Java better, though. When I go to code source, I like
having the object framework for helping me to decide where a method goes.
I think it almost forces me to do better work.

>In addition, the presentation is in OO terms, not files and source
>members or whatever. This reinforces the OO concepts of inheritance,
>etc., and may help in the admittedly difficult paradigm shift we need to
>make when moving to OO programming.

That would be because Java is OO and RPG is not, right?

>I think OO is a way of thinking, not a language. OO principles can guide
>the development process all the way from analysis to programming. It can
>be done in <bold>any</bold> language--it's just terribly hard to do it in
>RPGII or good old Dartmouth BASIC. It helps to have the programming
>language enforce the rules--are any of us disciplined enough, generally,
>to code everything that an OO environment requires?

It may be that you can program OO with any language, but it is arduously
difficult and thus not done. The principles of inheritance and
polymorphism are difficult to implement in some languages, impossible in
others. These are vital to really implementing OO solutions. That is why
there are certain qualifications required for a language to be OO. 

OO is a way of thinking, though. Many C programmers bought C++ compilers
and kept on writing C code. The language could not force them to write OO.
Once an application is built without being OO, it isn't possible to evolve
it into OO, it needs to be rewritten. 

So, RPG programmers should start now learning techniques that will take
them into the era of OO programming. It does sort of make sense. Consider
it, IBM has developed the finest, most reliable system in the world by
making it completely object oriented. So, how many developers have learned
from this example?

>Later
>Vernon Hamberg


Chris Rehm
Mr.AS400@ibm.net
You have to ask yourself, "How often can I afford to be unexpectedly out of 
business?" 
Get an AS/400.
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