Re: EGL and RPG in the web world

On 3/13/2012 9:53 PM, Steven Spencer wrote:

Non-trivial, and complex, updates and editing and special stuff exists in RPG programs all the time (not the standard update and query programs, but the complex stuff as in invoicing and inventory). It seems to me that what you are saying is that EGL is not natively very strong there, you need RPG's programming detail to get from square A to Z. If you tried to do it in EGL, you would end up generating code, and then maybe tweaking the code, but that runs into the problem that EGL is generating, as I understand, Cobol and Java, neither of which is as friendly to us as RPG. (And touching "generated" code is generally something you want to avoid. I remember some development environments, like Clarion, tried to make hooks into and out of generated code more practical, so you could regen without losing your work, but that is not the norm.) Thus it sounds to me that, in some cases, you have EGL performing a rather limited function, of jazzing up all the easy programs but passing on the heavy ones, which you will design and implement in good old RPG ? In that case how do you work the net-PC interface ? Are you combining some non-EGL tools with RPG ? Or do you use EGL in a more limited function, not 4GL, but web output, called by RPG ? I hope my question is clear, and maybe even sensible, I am simply trying to get a nice handle on the practical matters. Thanks. Steven Spencer Queens, NY

No, you've pretty completely missed the point. I primarily use EGL as SDA for the web (although the EGL people hate when I say that). It's a little more than that, but if all I did was to create the user interface and call services which in turn call RPG programs, then I would be fine with that. In many cases, though, it's faster to write the SQL query to load the UI using EGL rather than writing an RPG program which I call.

I would NEVER touch the generated code. That's just crazy talk. Especially since EGL does let you easily call RPG or Java to do those things which EGL wasn't intended to do. As to the "net-PC" interface I'd suggest reading any of my columns on EGL (or even buying my book <grin>) which shows exactly how easy it is to call an RPG program from EGL. EGL provides all the plumbing for your client code (written in EGL and generated to JavaScript running in the browser) to call your server code (written in EGL and generated to Java running on the host) which in turn calls your RPG code running on the host.

Really, it would take longer to write a post explaining multi-tiered EGL/RPG architecture than it would for you to write a sample EGL program. I have always championed using EGL as the UI for business logic written in RPG. You call it a limited function, I call it using the right too for the job. RPG doesn't do web, EGL doesn't do MRP.

Start here with an article I wrote on the topic nearly five years ago:

http://www.ibmsystemsmag.com/ibmi/developer/rpg/Using-EGL-and-RPG-Together/

Joe