Omnis Classic — AI Safety Guide

This page exists to prevent AI (and humans…) from introducing non-Classic syntax or incorrect assumptions into Omnis Classic code.

⚠️ Do Not Invent Commands

If a command is not explicitly known from Omnis Classic, do not guess.

❌ Incorrect (not Classic)

• Update record\
• Revert record\
• Quit data entry\
• evClick / On evClick / Do evClick

✅ Correct approach

• Use known Classic commands:
  • Update files
  • Cancel prepare for update
  • Prepare for update
• Or describe behaviour without inventing syntax

💾 File Updates (Classic)

In Omnis Classic:

Update files

• This is the correct command to save changes
• There is no Update record

Canceling an update cycle:

Cancel prepare for update

🔄 Prepare for Update Cycle

Typical pattern:

Prepare for update
... make changes ...
Update files

To cancel:

Cancel prepare for update

Notes:

• Always pair Prepare for update with either:
  • Update files, or
  • Cancel prepare for update
• Do not leave records locked

📂 Single File Find Behaviour

Omnis Classic works on the current file and current record buffer.

Common pattern:

Find on FAC_Seq
Prepare for update
...
Update files

AI must not rewrite this as:

• object-based record handling\
• updateRecord() style logic

🖱️ UI Event Handling (Classic)

Omnis Classic uses hash events:

• #Click
• #DClick

Do not introduce:

• evClick
• On evClick
• Do method

If unsure, refer to the event name only.

Debug Pattern: Safe Default with Conditional Breakpoint

In JACSoft Omnis Classic code, unexpected conditions may be handled by:

• continuing with a safe default behaviour
• optionally triggering a Breakpoint when a developer is logged in

Example:

Default
  If kb_JAC_Logged_in
    Breakpoint
  End If
  ... safe fallback ...

This allows production systems to continue running while still exposing issues during development.

🛡️ Business Logic Safety

Not all defensive checks in Omnis Classic are purely technical.

Examples include:

• divide-by-zero guards
• zero-value checks
• conditional recalculation paths

These often enforce business rules, not just runtime safety.

Important:

• Do not assume such checks can be simplified or removed
• Do not replace them with modern-style validation or exceptions
• Do not “optimise” logic without understanding user intent

Example pattern:

If LN_Factor=0
  ;; may preserve user-entered values or signal failure via #F
  ;; do not assume this should be replaced with recalculation
  

In many cases:

• the code is intentionally preserving user input
• or deliberately avoiding recalculation
• or signalling failure/exception via #F

Rule of thumb

If a condition prevents a calculation, it is likely protecting a business decision, not just avoiding an error.

When in doubt:

• follow existing behaviour
• do not modernise
• do not reinterpret intent

🧠 General Rules

• Omnis Classic is procedural, not object-oriented
• Field names are used directly
• Boolean values are 0 and 1
• pick() uses positional logic
• The system relies heavily on current file context

🧓 Final Rule

If it looks modern, it probably isn’t Classic.

When in doubt:

• Check existing JACSoft code
• Follow established patterns
• Do not improvise syntax