Re: Need some ammunition (Procedures vs. Sub-routines)

I think that this discussion is mixing things up.



There is no big difference in writing subroutines or procedures inline in a
program. Procedures may have an interface and may have local variables that
subroutines don’t have – that’s it!



Generic local subroutines or procedures can be copied into the program with
the use of the /COPY function and that has been used for decades.



Calling external programs isn’t new either. Before we had service program
we did do dynamical calls to other program. A service program is nearly
just the same since a service program can be seen as a collection of
external programs that in a service program are called procedures.



The benefit of procedures in a service program is that they share the same
global variables and thereby is able to “talk” with each other.



A service program needs pre-binding since it is a part of the ILE concept.
However it is rather easy to implement a binding strategy into an existing
system and the few challenges that follows are basically the same if you
already use /COPY for generic subroutines.



A service program also needs a binding source that enables the service
program to be backwards compatible without the need to recompile programs
that uses previous versions.



But why use service programs and why learn the basics?



Simply because service programs are all over the system and expands RPGLE
with special features that is not a part of RPGLE (HTTP, FTP, XML, JSON,
XLS, STMF etc. etc.) and they are directly comparable with imported Classes
and Methods in both C++ and JAVA.



I agree with Dieter that this has to be implemented on team level but with
a little guidance it can be done in less than a day and it is an investment
that is worthwhile.


On Sat, Dec 28, 2013 at 8:58 AM, D*B <dieter.bender@xxxxxxxxxxxx> wrote:

... maybe I should avoid to ger into political discussions...

<RPGLIST>
The reason I really think he pushed back, was a couple other programmers
complained about several other programs that were modified with procedures
and he's afraid of the push on this as well.
</RPGLIST>

The most important change from using Subroutines to writing procedures is:
programm creation is diffrent and more complicated and this will affect all
programmers in the team! If you don't use change management and if you
follow all recommendations in this list (and most of forums etc.), your
source will no more be selfcontained and you would need multiple sources to
create one programm. Besides /COPY includes you would have binding
directories and binder source and without ensuring, that this will be in
sync during the maintenance process, you might get programm changes by
accident (Pandorras box). This might happen because these ressources are
located by libl and even libl/membername.

And so the usage of procedures is a team desicion and the strategies for
programm creation have to be part of some standard and have to be assured.
It's not done by just starting to write procedures.

D*B
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