04
Mon, Nov
5 New Articles

RPG Academy: BIF Up Your Code! More on Moving MOVE and MOVEL out of Your Code

RPG
Typography
  • Smaller Small Medium Big Bigger
  • Default Helvetica Segoe Georgia Times

Understanding how to use the EVAL op code and the %CHAR, %EDITC, %EDITFLT, and %EDITW BIFs will help you remove even more of those MOVE and MOVEL statements from your code.

 

One of MOVEL's many uses is the implicit data type conversion from numeric to character. You probably have quite a few of these conversions in your code and don't even realize it. While they're not as error-prone as the reverse operation, it's preferable to have a more controlled conversion, especially because many of these operations are part of something that the end-user will seeeither a message on the screen or a line on a printout, for instance. As usual, there are several ways to do this.

 

Converting Numeric Data to Character with %CHAR

There’s not much to say about %EDITC, %EDITW, and %EDITFLT because they're quite straightforward. There are a few examples of each in this article. So let's start the article by discussing %CHAR. This BIF converts the value of the expression from numeric, date, time, or timestamp data (and others that I won't mention to keep things as simple as possible) to type character. The converted value remains unchanged but is returned in a format compatible with character data. In other words, the numeric value 123.456 becomes the string '123.456' when you pass it as the first parameter of %CHAR. Just like the BIFs presented in a previous TechTip, %CHAR has a mandatory parameterthe expression to be converted to character. It also has an optional parameter that allows you to specify the format in which the converted data will be presented. For instance, for a Date expression, you can specify *ISO in the format parameter:

 

D MyDate         S               D   INZ(D'2014/11/16')

D result         S           100A   VARYING

(…)

C                   EVAL    result = 'Today is ' + %CHAR(MyDate : *ISO)

* "result" is now 'Today is 2014-11-16'

 

However, you can use the format parameter only with certain data types, such as date, time, and timestamp, because those are the data types that have predefined formats. There's no predefined format for a decimal, for instance. So, to "beautify" a decimal expression when converting it to character, you need something else. If you think about it, you probably know the answer already: how do you format numeric fields on a display file? You use either an edit code or an edit word, right? Well, turns out that those familiar concepts also exist as BIFs. Let's go over %EDITC first.

 

Using Edit Codes and Edit Words to "Beautify" Numeric Data

The %EDITC BIF has two mandatory parameters: the numeric value to be converted and the edit code to apply. It also has an optional parameter that can have one of three values:

  • *ASTFILL, which replaces the leading zeros with asterisks. For example, %EDITC(-0012.3 : 'K' : *ASTFILL) returns '***12.3-'.
  • *CURSYM, which indicates that a floating currency symbol is going to be inserted in the converted string, just before the first significant (non-zero) digit. For instance, %EDITC(0045.6 : 'K' : *CURSYM) returns '   $45.6 '.
  • A user-specified currency symbol. It must be a 1-byte character constant (literal, named constant, or expression that can be evaluated at compile time). This means that %EDITC(0078.9 : 'K' : '£') will return '   £78.9 '.

If this isn't enough for you, you can always use %EDITW. It's similar to the DDS keyword, and you can use whatever edit word you want, as long as you follow some rules, described in the Parts of an Edit Word section of IBM's ILE RPG Reference Manual. Just to consolidate this, here's an example adapted from the same manual:

 

D amount         S             30A
D salary         S             9P 2
D editwd         C                   '$ ,   , **Dollars& &Cents'
 
 * If the value of salary is 2451.53, then the edited version of
 * (salary * 12) is '$***29,418*Dollars 36 Cents'. The value of
 * amount is 'The annual salary is $***29,418*Dollars 36 Cents'.
 
 
C                   EVAL    amount = 'The annual salary is '
                            + %EDITW(salary * 12 : editwd)

 

Just a note of caution: neither BIF accepts float expressions. If you need to convert a float, then convert it to decimal format first, using either %DEC or the %EDITFLT BIF. I usually don't use the %EDITFLT BIF because it returns the float expression as the character external display representation of float. For example, if you have a float variable containing 2.3, applying %EDITFLT to it will return the string "+2.299999999999999E+000". It might not be exactly what your user is expecting, so it might be best to use %DEC, customizing the precision and decimal places to your needs. This can be achieved in a single step, using a BIF within another BIF, something like %EDITC(%DEC(<float variable name> : <precision> : <decimal places>) : <edit code> ).

 

Yet Another Use of MOVE You Can Do Without

Finally, there's yet another common use of MOVE and MOVEL that you probably have in your code: sometimes a customer ID or a product code is a big number, but in reality is a concatenation of two or more codes. For instance, I've seen customer IDs that started with the sales channel, followed by the customer country ISO code, and ended with the customer number. At first glance, it's simply a huge number that's being decomposed using MOVE, MOVEL, and three variables. In this type of situation, you can use an EVAL op code and a data structure to replace those pesky MOVEs. Let's take this example and assume that the complete customer ID has 10 characters: 1 for the sales channel, 3 for the ISO country code, and 6 for the customer ID. You'd use a series of MOVE and MOVEL statements to extract each part from the customer ID.

 

Or you can use a data structure that mimics the internal structure of the customer ID, like this:

 

D                 DS              

D CUST_ID               1     10

D SAL_CHN               1     1

D COUNTRY               2     4

D CUST_NBR               5     10

D P_CUST_ID       S             10   INZ('1351000024')

(…)

* Using the data structure fields to decompose the customer id

C                   EVAL    CUST_ID = P_CUST_ID
 * After this operation: SAL_CHN = '1', COUNTRY = '351'
 * and CUST_NBR = '000024'

 

It's not mandatory that all fields of the data structure share the same type; you can mix types freely. Just be careful because, as I said before, the implicit conversions might not always work as you expect. A side note: another way to define a data structure involves using the OVERLAY keyword instead of the from/to positions. I'll talk about that later in the series.

 

That's all for now! The next TechTip will continue to explore the BIFs RPG provides, focusing on the ones that are related to string operations.

 

I hope that these tips will help you remove MOVE and MOVEL from your source code. Contribute with your own techniques, ideas, and questions in the comments section below or in the LinkedIn groups where these TechTips usually pop up.

 

Rafael Victoria-Pereira

Rafael Victória-Pereira has more than 20 years of IBM i experience as a programmer, analyst, and manager. Over that period, he has been an active voice in the IBM i community, encouraging and helping programmers transition to ILE and free-format RPG. Rafael has written more than 100 technical articles about topics ranging from interfaces (the topic for his first book, Flexible Input, Dazzling Output with IBM i) to modern RPG and SQL in his popular RPG Academy and SQL 101 series on mcpressonline.com and in his books Evolve Your RPG Coding and SQL for IBM i: A Database Modernization Guide. Rafael writes in an easy-to-read, practical style that is highly popular with his audience of IBM technology professionals.

Rafael is the Deputy IT Director - Infrastructures and Services at the Luis Simões Group in Portugal. His areas of expertise include programming in the IBM i native languages (RPG, CL, and DB2 SQL) and in "modern" programming languages, such as Java, C#, and Python, as well as project management and consultancy.


MC Press books written by Rafael Victória-Pereira available now on the MC Press Bookstore.

Evolve Your RPG Coding: Move from OPM to ILE...and Beyond Evolve Your RPG Coding: Move from OPM to ILE...and Beyond
Transition to modern RPG programming with this step-by-step guide through ILE and free-format RPG, SQL, and modernization techniques.
List Price $79.95

Now On Sale

Flexible Input, Dazzling Output with IBM i Flexible Input, Dazzling Output with IBM i
Uncover easier, more flexible ways to get data into your system, plus some methods for exporting and presenting the vital business data it contains.
List Price $79.95

Now On Sale

SQL for IBM i: A Database Modernization Guide SQL for IBM i: A Database Modernization Guide
Learn how to use SQL’s capabilities to modernize and enhance your IBM i database.
List Price $79.95

Now On Sale

BLOG COMMENTS POWERED BY DISQUS

LATEST COMMENTS

Support MC Press Online

$

Book Reviews

Resource Center

  • SB Profound WC 5536 Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application. You can find Part 1 here. In Part 2 of our free Node.js Webinar Series, Brian May teaches you the different tooling options available for writing code, debugging, and using Git for version control. Brian will briefly discuss the different tools available, and demonstrate his preferred setup for Node development on IBM i or any platform. Attend this webinar to learn:

  • SB Profound WP 5539More than ever, there is a demand for IT to deliver innovation. Your IBM i has been an essential part of your business operations for years. However, your organization may struggle to maintain the current system and implement new projects. The thousands of customers we've worked with and surveyed state that expectations regarding the digital footprint and vision of the company are not aligned with the current IT environment.

  • SB HelpSystems ROBOT Generic IBM announced the E1080 servers using the latest Power10 processor in September 2021. The most powerful processor from IBM to date, Power10 is designed to handle the demands of doing business in today’s high-tech atmosphere, including running cloud applications, supporting big data, and managing AI workloads. But what does Power10 mean for your data center? In this recorded webinar, IBMers Dan Sundt and Dylan Boday join IBM Power Champion Tom Huntington for a discussion on why Power10 technology is the right strategic investment if you run IBM i, AIX, or Linux. In this action-packed hour, Tom will share trends from the IBM i and AIX user communities while Dan and Dylan dive into the tech specs for key hardware, including:

  • Magic MarkTRY the one package that solves all your document design and printing challenges on all your platforms. Produce bar code labels, electronic forms, ad hoc reports, and RFID tags – without programming! MarkMagic is the only document design and print solution that combines report writing, WYSIWYG label and forms design, and conditional printing in one integrated product. Make sure your data survives when catastrophe hits. Request your trial now!  Request Now.

  • SB HelpSystems ROBOT GenericForms of ransomware has been around for over 30 years, and with more and more organizations suffering attacks each year, it continues to endure. What has made ransomware such a durable threat and what is the best way to combat it? In order to prevent ransomware, organizations must first understand how it works.

  • SB HelpSystems ROBOT GenericIT security is a top priority for businesses around the world, but most IBM i pros don’t know where to begin—and most cybersecurity experts don’t know IBM i. In this session, Robin Tatam explores the business impact of lax IBM i security, the top vulnerabilities putting IBM i at risk, and the steps you can take to protect your organization. If you’re looking to avoid unexpected downtime or corrupted data, you don’t want to miss this session.

  • SB HelpSystems ROBOT GenericCan you trust all of your users all of the time? A typical end user receives 16 malicious emails each month, but only 17 percent of these phishing campaigns are reported to IT. Once an attack is underway, most organizations won’t discover the breach until six months later. A staggering amount of damage can occur in that time. Despite these risks, 93 percent of organizations are leaving their IBM i systems vulnerable to cybercrime. In this on-demand webinar, IBM i security experts Robin Tatam and Sandi Moore will reveal:

  • FORTRA Disaster protection is vital to every business. Yet, it often consists of patched together procedures that are prone to error. From automatic backups to data encryption to media management, Robot automates the routine (yet often complex) tasks of iSeries backup and recovery, saving you time and money and making the process safer and more reliable. Automate your backups with the Robot Backup and Recovery Solution. Key features include:

  • FORTRAManaging messages on your IBM i can be more than a full-time job if you have to do it manually. Messages need a response and resources must be monitored—often over multiple systems and across platforms. How can you be sure you won’t miss important system events? Automate your message center with the Robot Message Management Solution. Key features include:

  • FORTRAThe thought of printing, distributing, and storing iSeries reports manually may reduce you to tears. Paper and labor costs associated with report generation can spiral out of control. Mountains of paper threaten to swamp your files. Robot automates report bursting, distribution, bundling, and archiving, and offers secure, selective online report viewing. Manage your reports with the Robot Report Management Solution. Key features include:

  • FORTRAFor over 30 years, Robot has been a leader in systems management for IBM i. With batch job creation and scheduling at its core, the Robot Job Scheduling Solution reduces the opportunity for human error and helps you maintain service levels, automating even the biggest, most complex runbooks. Manage your job schedule with the Robot Job Scheduling Solution. Key features include:

  • LANSA Business users want new applications now. Market and regulatory pressures require faster application updates and delivery into production. Your IBM i developers may be approaching retirement, and you see no sure way to fill their positions with experienced developers. In addition, you may be caught between maintaining your existing applications and the uncertainty of moving to something new.

  • LANSAWhen it comes to creating your business applications, there are hundreds of coding platforms and programming languages to choose from. These options range from very complex traditional programming languages to Low-Code platforms where sometimes no traditional coding experience is needed. Download our whitepaper, The Power of Writing Code in a Low-Code Solution, and:

  • LANSASupply Chain is becoming increasingly complex and unpredictable. From raw materials for manufacturing to food supply chains, the journey from source to production to delivery to consumers is marred with inefficiencies, manual processes, shortages, recalls, counterfeits, and scandals. In this webinar, we discuss how:

  • The MC Resource Centers bring you the widest selection of white papers, trial software, and on-demand webcasts for you to choose from. >> Review the list of White Papers, Trial Software or On-Demand Webcast at the MC Press Resource Center. >> Add the items to yru Cart and complet he checkout process and submit

  • Profound Logic Have you been wondering about Node.js? Our free Node.js Webinar Series takes you from total beginner to creating a fully-functional IBM i Node.js business application.

  • SB Profound WC 5536Join us for this hour-long webcast that will explore:

  • Fortra IT managers hoping to find new IBM i talent are discovering that the pool of experienced RPG programmers and operators or administrators with intimate knowledge of the operating system and the applications that run on it is small. This begs the question: How will you manage the platform that supports such a big part of your business? This guide offers strategies and software suggestions to help you plan IT staffing and resources and smooth the transition after your AS/400 talent retires. Read on to learn: