What do you do when 15 characters just aren't enough?
If you're like me, you've become so used to abbreviating names for fields, data structures, prototypes, and subprocedures to stay within the 15-character limit that it's become part of your programming psyche. But what if there was a way to remove the limit of the length for these objects? As you may have already guessed, that's what this article is all about.
How Many Characters Are Enough?
You may be of the mindset that the 15-character limit should be plenty, but in some circumstances, the ability to extend beyond that limit can be very helpful in creating well-defined, easy-to-understand code. A good example of this might be defining groups of associated prototypes, where a portion of the name is used to identify that grouping.
Removing the 15-character limit can also help you avoid potentially confusing abbreviations. You may alsobe someone who likes to indent field names within the data structure and/or prototype definitions. When you work within the 15-character limit, your indented field names actually have to deal with a smaller limit.
Having said that, it's also important to avoid the temptation to go too far in using long naming techniques. You don't want to run into situations where you can't use the field within your C-specs.
Coding the Definition Specs
Field, data structure, and subprocedure prototype names are all created within your program's definition ("D") specs. Below are examples of some standard D-specs.
* Standalone field definition
DstrCstShpToFNme S 35A
* Data Structure definition
DdsFltPrmDfnStr DS Qualified Dim(10)
D FltStr 35A
D FltType 2 0
* Procedure prototype
DprcClcOrdShpCh PR 15 5
D parOrdNbr 9 0
D parShpDt D
In these examples, the standalone field is defined as a 35-character alpha field that will be used to store the customer ship-to first name. The second definition is for a data structure containing two subfields. This data structure is intended to store information used to define filter parameter strings. The final example is a procedure prototype for a procedure that is used to calculate order shipping costs. While these may be clear enough from the 15-character values shown, using abbreviations like these can lead to confusion. Let's look at how we can make these names more clear.
A Total Ellipsis
The key to extending names in your definition specs is the use of the ellipsis. The simple "..." string gives us the ability to create a name longer than 15 characters. In fact, you can string multiple definition lines together using multiple ellipses to create an almost-limitless name. The remaining definition parameters are then placed on the line immediately after the line containing the ellipsis.
Let's look at our earlier examples, redefined using longer names. First off, our standalone field might be defined as shown here:
* Standalone field definition
DstringCustomerShipToFirstName...
D S 35A
In this example, our field name is now stringCustomerShipToFirstName instead of strCstShipToFNme.
Below is a modified example of the data structure defined earlier:
* Data Structure definition
DdataStrFilterDefinitionString…
D DS Qualified Dim(10)
D FilterString 35A
D FilterType 2 0
Note that in this example the subfield names are also more descriptive, even though these more-descriptive names are shorter than the 15-character limit. This is done here for consistency purposes.
Finally, let's examine the subprocedure definition.
* Procedure prototype
DprocCalcOrdeShipmentCharges…
D PR 15 5
D parmOrderNumber…
D 9 0
In this example, both the procedure name and the procedure parameter are defined using long naming techniques. It's actually possible to take this technique and create extremely long names, as shown below:
DstringSomeLongFieldName...
DThatsTooLongToFitOnASingle...
DLineAndNeedsToBeExtendedTo...
DFourLines...
D S 35A
The result of this would be a field named
stringSomeLongFieldNameThatsTooLongToFitOnASingleLineAndNeedsToBeExtendedToFourLines
As a side note, if I ever saw this used in a program, I would hunt down the programmer who coded it. This does, however, help to illustrate how to overcome the 15-character name limit.
Powerful Technique
I think a quote from Ben Parker (yes, Spiderman's uncle) might say it best, "With great power comes great responsibility...." In this case, that great power is the perceived 15-character naming limit in ILE RPG programs. While this technique gives you that power, it's important to use that power responsibly and not create long names just for the sake of creating long names.
Mike Faust is a senior consultant/analyst for Retail Technologies Corporation in Orlando, Florida. Mike is also the author of the books Active Server Pages Primer, The iSeries and AS/400 Programmer's Guide to Cool Things, JavaScript for the Business Developer, and SQL Built-in Functions and Stored Procedures. You can contact Mike at
MC Press books written by Mike Faust available now on the MC Press Bookstore.
 |
||
 |
|
Active Server Pages Primer Learn how to make the most of ASP while creating a fully functional ASP "shopping cart" application. List Price $79.00 Now On Sale
|
|
||
 |
|
JavaScript for the Business Developer Learn how JavaScript can help you create dynamic business applications with Web browser interfaces. List Price $44.95
Now On Sale
|
|
||
 |
|
SQL Built-in Functions and Stored Procedures Unleash the full power of SQL with these highly useful tools. List Price $49.95
Now On Sale
|
More 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.
TRY 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.
Forms 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.
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:
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.
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:
LATEST COMMENTS
MC Press Online