Jon Paris
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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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Guru: An Introduction to RPG’s XML-INTO, Part 1
August 1, 2018 Jon Paris
Author’s Note: The original version of this article was written in the V6 timeframe and included references to V5R4. References to the V5R4 limitations have been removed from this updated version. I have also updated the data definitions to take into account RPG’s ability for the direct coding of nested data structures rather than having to use LikeDS as before.
RPG IV’s built-in XML support has been available for some time now, having been originally introduced with V5R4 back in 2006. However, it wasn’t until the advent of V6 with its removal of many of RPG’s size limits that it …
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Guru: RPG’s New DATA-INTO
June 18, 2018 Jon Paris
In this tip I’m going to give a brief introduction to the latest addition to the RPG language. The new DATA-INTO op-code. DATA-INTO is IBM’s response to the oft-asked question: “When is IBM going to introduce JSON-INTO so we can process JSON as easily as XML?”
DATA-INTO provides this capability, but IBM has very cleverly given it functionality that goes way beyond what a simple JSON-INTO op-code could ever have done. DATA-INTO is effectively a cross between XML-INTO and Open Access. Like XML-INTO it uses the names of items and their hierarchy to unpack the document into RPG variables. Like …
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Guru: Dealing With Non-Normalized Data
April 9, 2018 Jon Paris
From time to time, many of us have to find solutions for handling our old non-normalized tables in an efficient manner. It would be nice to have the luxury of redesigning and normalizing these databases, but real life is not like that. This is particularly true when the tables in question are part of an application package where you have no control over the file layout.
I should point out that by “efficient” in this context I don’t necessarily mean processing speed, but rather in terms of the number of lines of code needed to perform the necessary manipulations and/or …
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Guru: Searching Teraspace
March 5, 2018 Jon Paris
In my previous tip, Sorting In Teraspace, I looked at how the qsort API can be used to sequence data in ways that SortA can’t begin to approach. Now that the data is sorted, one of the things I may want to do with it is to search it. In this tip I will look at how that can be achieved using the bsearch API. The approach I will be discussing allows for partial key searches and handling the fact that such a search may result in multiple hits.
As you will see when we work through the code, …
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Guru: Sorting In Teraspace
January 29, 2018 Jon Paris
In an earlier tip, Teraspace To The Rescue, I discussed how to use teraspace in RPG to permit the storage and manipulation of data that requires more storage than RPG’s 16MB limit. In this tip I am going to discuss how such data can be sorted. Hint: SORTA won’t work!
Before I get to that though, there is one thing I should mention. In that original tip I said: “For reasons I have never understood, DEALLOC will not null your pointer. So it is a good idea to do it yourself. . . .” IBM’s Barbara Morris pointed out, …
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Guru: Teraspace To The Rescue
August 14, 2017 Jon Paris
Hey, Jon:
My team has been trying to resolve a problem for the last few weeks and they are running into several obstacles. The main one has to do with RPG restrictions for data structure length.
We use a third-party program to process transactions. In the latest version, the vendor has increased the length of the fields in the data structure that we have to pass them. After our programs were changed to accommodate this increase, the RPG program would not compile because the DS exceeds 16,733,104 bytes. The vendor has told us to use teraspace but by itself that …
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Guru: Fundamentals Of Prototyping, Part 1
July 24, 2017 Jon Paris
In my series on parameter passing fundamentals, I mentioned the importance of using prototypes to help ensure consistency of parameter definitions; i.e., to help ensure that the parameter passed to the called routine matches what is expected. After that article was published, it came to my attention that many of my readers were unaware of some of the additional capabilities of prototypes, in particular that prototypes can not only identity errors in parameter usage, but that in some cases they can actually fix them for you!
Before we can begin, though, it would be a good idea to ensure that …
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