[RPGNext] ILE in practice

[Joel Cochran <jrc@xxxxxxxxxx>]

Howdy Nexters!

Since we haven't had any discussions yet, I wanted to share with you all
a question I got on Friday about one of the articles.  I thought it may
be of interest, so below is the original message and my response.

This may also be a good segue into a discussion of prototyping in
general....

Joel

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On Thu, 2004-07-08 at 21:26, jgriffin@xxxxxxxx wrote:
> 
> 
> Joel,
> 
> I have enjoyed your articles on ILE published at
www.midrangeserver.com.  I
> am going over the code for the MyMaint rpg program and have a
question.
> What is the function of the following lines?
> 2400 d MYMAINT                      PR
> 2600 d MYMAINT                      PI
> 
> Are we establishing a procedure interface to this application?  I
commented
> the lines out to see what would happen and the porgram appears to
function
> as before?  Thank you again for you articles and very useful examples.

Yes, you are establishing a procedural interface to this application. 
This approach is how you replace *ENTRY PLIST with prototypes and
procedural interfaces.  This source provides the single *MODULE object
for a program.  As a bona-fide program, it can be called from a command
line or dynamically called from another program, etc.  In the old style,
if there were parameters for calling this program there would be an
*ENTRY list.  This set of PR/PI replaces *ENTRY.  In this case there are
no parameters so you don't actually need it, just like you wouldn't need
a *ENTRY for a program with no parameters, but I picked up the habit of
including this for all my main modules.  I like the consistency and
clarity, but technically in this case it serves no real purpose.