Re: PowerExt (www.PowerExt.com)

I don't find traditional JavaScript to be highly prone to error, but the JavaScript Object Notation used to define widgets in ExtJs and similar libraries, is. It's both prone to error, and hard to debug. It was good to see them coming out with a WYSIWYG designer.

I don't fully understand your suggestion for storing UI elements in DB2 tables. I assumed the ExtJs designer would output stream files, which could be used as templates, with substitution variables, where needed.

Nathan
http://www.relational-data.com



----- Original Message ----
From: Aaron Bartell <aaronbartell@xxxxxxxxx>
To: Web Enabling the AS400 / iSeries <web400@xxxxxxxxxxxx>
Sent: Thu, December 31, 2009 12:23:09 PM
Subject: Re: [WEB400] PowerExt (www.PowerExt.com)

It appears to me that a key to generating RUI applications is to embed RUI

widgets in standard HTML pages, use a template engine to dynamically
generate pages, then have high-level RPG procedures asynchronously supplying
properly formatted data streams to data-bound widgets.

That is exactly my thoughts on the matter!

Let me run this thought past you...

What if the definition of a grid was configured via DB2 tables, similar to
how a *DSPF has it's screen stored in DSS? Then a programmer could
configure a screen and corresponding UI components outside of the highly
error prone syntax of Javascript. For performance considerations you could
serialize the DB2 representation of a grid into a stream file (or *USRSPC)
so there was less data I/O, and then you could have "switches" that stated
whether or not a cached version of a screen should be used or if it should
be obtained from the DB2 tables.

In the end, if we have programmers coding HTML, CSS, or Javascript, then I
think we missed the mark because that is where the most time is wasted.

Now imagine if we allowed programmers to create screens using the ExtJS
Designer and store the created form in those aformentioned DB2 tables for
both initial creation and maintenance purposes:
http://www.extjs.com/api/xds/screencasts/designer.html

Thoughts?
Aaron Bartell



On Wed, Dec 30, 2009 at 11:11 PM, Nathan Andelin <nandelin@xxxxxxxxx> wrote:

Hi Aaron,

It appears to me that a key to generating RUI applications is to embed RUI
widgets in standard HTML pages, use a template engine to dynamically
generate pages, then have high-level RPG procedures asynchronously supplying
properly formatted data streams to data-bound widgets.

Here's an example that you will relate to, since it was derived in part
from the Pet Store Item List that you provided in your RPGUI library.

http://www.radile.com/rdweb/temp/petitems.pdf

Note that a JSON formatted data stream is generated in the RPG "loadgrid"
subroutine by mapping the internal record buffer "itemrec" to a JSON array
object. The jsoRecWrt() procedure is a remarkably streamlined procedure for
mapping fields from any internal record buffer to a JSON object. It really
streamlines the interface for the programmer.

You can compare that to the jsonNode() procedure in PowerExt, which in
contrast requires developers to write substantially more lines of code.

Nathan.