Jon Paris
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Guru Classic: Where Does Data Live? The New Basics
June 19, 2019 Jon Paris
Every time I teach some of the more recent additions to RPG, such as XML parsing or Open Access, I find that I need to include some “remedial” education on some of the data definition enhancements that have been made to the language over recent releases.
Most of these enhancements came into the language many years ago back in the days when D-specs were de rigueur, but if you had no immediate need for them, they may have passed you by. After all, even the most avid reader of this newsletter has probably forgotten most of what they read here …
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Guru: 7.4 Brings New RPG Goodies
June 3, 2019 Jon Paris
As I’m sure you know by now, IBM recently announced version 7.4 of IBM i. Along with major enhancements such as Db2 Mirror, we also got a number of new RPG features. In this tip I’ll cover those that are already available in 7.3 via PTF. The 7.4-only enhancements will be covered in a subsequent tip.
Before we get into the details of the 7.3 features, just a hint of what is to come . . . 7.4 brings the long-awaited arrival of dynamic arrays known to IBM as varying dimension arrays. No more do you have to compromise between …
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Guru: Open Access To The Rescue – The Next Step
May 6, 2019 Jon Paris
I recently wrote a tip on using an Open Access handler to enable the creation of flat files in the IFS. In that version of the handler I generated a generic file name and used hard-coded record delimiters and code page settings. I mentioned at the time that I would normally supply these values at run time. In this follow-on tip I describe how the handler can be modified to use the Open Access User Parameter to facilitate this.
The User Parameter is simply specified as a second parameter to the HANDLER keyword. It can be a simple variable or, …
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Guru Classic: A Bevy of BIFs, %XLATE and %REPLACE
March 6, 2019 Jon Paris
Author’s Note: I’m revisiting this classic tip since the original was written back in 2009, long before the introduction of free-form data declarations. In addition, I’ve updated this tip to point to the new %SCANRPL BIF, which impacts this scenario. And, of course, I still regularly encounter RPGers who are confused by the differences between the %XLATE and %REPLACE built-in functions (BIFs). Part of that confusion of course is the result of wishful thinking on the part of those frustrated by the limitations of %XLATE!
The first thing to remember when deciding which function to use is that %XLATE operates …
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Guru Classic: A Bevy of BIFs — %CHAR, %EDITC and %EDITW
February 13, 2019 Jon Paris
Author’s Note: The reason I chose this particular tip to revisit was that a similar question came up on one of the RPG web forums the other day. The questioner was looking for an easy way to edit a numeric field to include the use of colons as separators. Because the answer involves the use of %EditW I have added a simple example of its use at the end of this tip.
“I need to convert a numeric value into a character string. How do I . . . ?” This question is often asked by RPGers as they face …
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Guru: Open Access To The Rescue
February 11, 2019 Jon Paris
Recently I came upon a couple of questions on internet lists asking for an easy method to create flat files in the IFS. Not CSV files, but rather simple text files where individual data items are in fixed character positions. Various somewhat convoluted solutions were offered to the requestors, but to me this problem shouted “Open Access!”
So, I set about quickly building an Open Access (OA) handler to perform the task. I find OA really useful for this kind of job because, once the handler is written, creating these kinds of files in the future become a trivial task, …
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Guru Classic: A Bevy of BIFs – %SCAN and %CHECK
January 16, 2019 Jon Paris
Many RPG programmers seem to get confused about the usage and operation of a number of built-in functions (BIFs). In particular the BIFs %XLATE, %REPLACE, %SCAN, and %CHECK seem to cause a lot of confusion. In this tip, I focus on %CHECK and %SCAN. I decided to re-visit this particular tip because of the recent introduction of %SCAN’s companion BIF %SCANR and a related enhancement to %SCAN itself. More on this later.
The %SCAN BIF has been with us since V3R7, when it was introduced along with %EDITC and %EDITW, to improve string handling. %CHECK, on the other hand, is …
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Guru: When Is An Error Not An Error?
November 26, 2018 Jon Paris
When is an error not an error? When it is expected! In this article I want to discuss the use of RPG’s MONITOR op-code and discuss ways in which it might change the way you code RPG. I was prompted to write up my thoughts on this subject as a result of being quizzed by students at a recent RPG & DB2 Summit as to why I was using Monitor blocks rather than more conventional RPG techniques in my examples.
So what do I mean by expected? Basically I mean those errors that you know are going to happen …
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Guru: An Introduction to Processing XML With RPG, Part 3
September 5, 2018 Jon Paris
Author’s Note: In part 1 and part 2 of this XML series, I introduced you to the basics of using RPG’s XML support. In this tip we begin to explore some of the challenges that you may face when processing commercial XML documents, and the support XML-INTO offers to handle them. In particular we will be reviewing how to ignore parts of the document through the use of the path= %XML option. We will also review how to handle XML documents that make use of namespaces and how to handle XML element names that include characters that are not valid …
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Guru: An Introduction to Processing XML With RPG, Part 2
August 29, 2018 Jon Paris
In the first part of this series for Guru Classic, I introduced you to the basics of using RPG’s XML-INTO op-code. In that tip I showed how the provision of a count provided by RPG in the PSDS can be used to determine how many of a repeating element were processed.
However, as I noted at the time, this can only be used when handling a repeating outer element. But what if there is a repeating element within each of those outer elements? In this second part of the series we will be studying how to handle those situations. …
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