Once you know what RPGLE is and how source becomes a program object, the next question is how the source itself is written.
If you want the full foundation path first, start with “RPGLE for Beginners: A Practical IBM i Learning Path” and “What RPGLE Is and Where It Fits on IBM i.”
This lesson compares the three source styles beginners are most likely to meet: fixed format, free format, and fully free RPGLE.
The goal is recognition first. You do not need a full syntax reference to understand the differences.
Estimated reading time: 8 minutes
Quick Summary
- Fixed format is the older column-driven style.
- Free format relaxed many of the column rules.
- Fully free RPGLE gives the most flexible source layout in this comparison.
- Mixed codebases can contain more than one style.
- Beginners should learn to recognize all three before choosing a starting style.
Reader Prerequisites
You should already know what RPGLE is and where it fits on IBM i from “What RPGLE Is and Where It Fits on IBM i.”
You should already understand source members and program objects at a high level.
You do not need a full syntax reference.
You do not need tooling knowledge yet.
If you need the platform picture first, read What Is AS400 (IBM i)? A Complete Beginner’s Guide.
For adjacent platform context, read IBM i Modernization Basics.
Learning Outcomes
- Identify fixed, free, and fully free RPGLE at a glance.
- Explain why fixed format existed in the first place.
- Describe what free format changed for beginners.
- Explain what fully free RPGLE means in practical terms.
- Compare the three styles without treating this as a full syntax guide.
- Decide what the first learning priority should be in a mixed codebase.
Why the Formats Exist
Fixed format came from an era when source layout carried a lot of meaning.
The language had to fit the tooling and programming constraints of its time.
Free format changed the experience by reducing column dependence for many calculations and statements.
That made code easier to read and easier to extend in many workflows.
Fully free RPGLE takes that idea further by removing the need to begin source with traditional fixed-specification columns.
It does not erase history.
It simply gives the most flexible source layout in this comparison.
Fixed Format at a Glance
Fixed format is the style many readers still encounter in older IBM i code.
It uses specific columns for specific parts of a statement.
That makes the layout feel strict, but it also explains why old code can look unfamiliar at first glance.
The important beginner takeaway is simple:
- Fixed format is historical, not mysterious.
- You do not need to memorize every column before you can understand the overall article series.
Free Format at a Glance
Free format reduced the dependence on exact columns.
That made source easier to scan and easier to maintain.
It still belongs to the same RPGLE family.
It is not a different language.
It is a different style of expressing the same kind of logic.
Fully Free RPGLE at a Glance
Fully free RPGLE goes even further toward flexible source layout.
Many beginners find it easier to approach because the statements read more like ordinary code and less like a layout puzzle.
That does not mean every older system will use it everywhere.
Mixed estates are common, so beginners should still learn to recognize fixed and free forms.
Side-by-Side Examples
These short examples show the same simple idea in each style.
In real fixed-format RPG source, column positions matter.
They help the compiler interpret factors, operation codes, and result fields.
The example below is intended only to help you recognize the style.
Fixed format
Col 6 Factor 1 Op Factor 2 Result
C amount ADD tax total
Free format
total = amount + tax;
Fully free RPGLE
**free
total = amount + tax;
The point of the examples is recognition.
They are intentionally small so you can focus on the layout difference, not on the surrounding program structure.
Comparison Matrix
| Style | Cue | Reader note | Often seen in |
|---|---|---|---|
| Fixed format | Column-driven | Harder at first | Older code |
| Free format | Fewer column rules | Easier to scan | Evolved codebases |
| Fully free RPGLE | Flexible layout | Often easiest | Newer standards |
The matrix is the practical view.
It helps you see which style you are reading before you try to understand the logic itself.
Actual usage depends on release level, local standards, and application history.
Which Format Am I Looking At?
Use this quick decision guide when you open source for the first time:
- Do the statements depend heavily on column position? If yes, you are probably looking at fixed format.
- Do the lines read more like ordinary statements but still show some legacy habits? If yes, you may be looking at free format.
- Do the statements read cleanly with minimal layout pressure and a modern style? If yes, you are probably looking at fully free RPGLE.
- If the source mixes styles, do not panic. Mixed estates are common.
Real source can mix styles. Use this guide as a first recognition clue, not as a complete parser.
You may also encounter comments, declarations, control options, file definitions, and mixed-format sections.
The main goal is to identify the style before you decide how to read the logic.
Common Beginner Misconceptions
- Fixed format is obsolete everywhere. It is not.
- Free format and fully free RPGLE are different names for the same thing. They are not.
- I must master fixed format before I can learn modern RPGLE. You do not.
- Mixed code means the codebase is broken. Not necessarily.
- Format style tells me everything about the program. It does not.
- I can ignore team standards once I know the modern style. You should follow the coding standards and supported compiler level of your IBM i environment.
FAQ
What is fixed format RPGLE?
It is the older RPGLE style that depends more heavily on column layout.
What changed with free format?
Free format reduced the dependence on fixed columns and made source easier to read.
What is fully free RPGLE?
It is the most flexible source layout in this comparison and often a good starting point for beginners.
Why do older programs still use fixed format?
Because many IBM i codebases are long-lived and were written before modern style became common.
Can fixed and free format live in the same codebase?
Yes. Mixed estates are common on IBM i.
Can one RPGLE source member contain more than one style?
Yes, a source member may contain more than one style in some environments and codebases. Beginners should recognize the styles first, then follow local standards before changing anything.
Which format should I learn first?
Start with the style your team uses most, but learn to recognize all three.
Do I need a full syntax reference now?
No. This lesson is about recognition and comparison, not complete syntax coverage.
What should I learn after this article?
Next, read “RPGLE Development Environments and Tooling Basics.”
Key Takeaways
- Fixed format, free format, and fully free RPGLE are different source styles.
- The styles exist because RPGLE evolved over time.
- Beginners should learn to recognize each style before trying to memorize every detail.
- Mixed codebases are normal.
- The next lesson moves from source style to tooling and workflow.
- If you need the broader learning path first, return to “RPGLE for Beginners: A Practical IBM i Learning Path.”
Continue Your Learning
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