zCobol Validation

Visual Studio Code extension that provides advanced validations for COBOL programs, helping maintain code quality and programming best practices.

Features

🔍 Available Validations

1. Unused Variables

Detects variables declared in WORKING-STORAGE or LINKAGE SECTION that are not used in the code.

• ✅ Quick Fix: Delete line or comment with asterisk
• 🎯 Severity: Warning
• 🔧 Smart Detection:
  • Considers level 88 conditions: a variable is marked as "used" if any of its 88-level conditions are used
  • Ignores FILLER and FILLER-* variables
  • Ignores group-level variables (variables without PIC that contain sub-variables)

2. Unprotected Displays

Identifies DISPLAY commands that are not inside IF blocks.

• ✅ Quick Fix: Wrap with IF...END-IF, comment or delete
• 🎯 Severity: Warning

3. GO TO Commands

Alerts about GO TO usage, suggesting refactoring with PERFORM.

• ✅ Quick Fix: Comment or delete
• 🎯 Severity: Warning

4. IFs without END-IF

Detects IF blocks that don't have a matching END-IF.

• ✅ Quick Fix: Add END-IF automatically
• 🎯 Severity: Error

5. IFs without ELSE (Optional - disabled by default)

Identifies IF blocks without ELSE clause.

• ✅ Quick Fix: Add ELSE or ELSE with CONTINUE
• 🎯 Severity: Warning

6. EVALUATE without WHEN OTHER (Optional - disabled by default)

Detects EVALUATE blocks without WHEN OTHER clause.

• ✅ Quick Fix: Add WHEN OTHER or WHEN OTHER with CONTINUE
• 🎯 Severity: Warning

7. Symbolic Operators

Identifies use of symbols (<, >, =, <=, >=, <>) in IF and WHEN conditions, suggesting appropriate COBOL keywords.

• ✅ Quick Fix: Automatically replace with LESS THAN, GREATER THAN, EQUAL, etc.
• 🎯 Severity: Warning
• ⚙️ Configurable: Long or short format

8. Hardcoded Values

Detects string and number literals in code, suggesting constant creation.

• ✅ Quick Fix: Create constant automatically in WORKING-STORAGE
• 🎯 Severity: Warning
• ⚙️ Configurable: Enable/disable in STRING, DISPLAY

9. Lowercase Code (Optional - disabled by default)

Identifies lowercase code (COBOL should be uppercase).

• ✅ Quick Fix: Convert to uppercase
• 🎯 Severity: Warning

10. File Operations

Checks if declared files (SELECT) have all necessary operations:

• OPEN

• CLOSE

• READ or WRITE

• 🎯 Severity: Warning

11. Cursor Operations

Checks if declared SQL cursors have all necessary operations:

• OPEN

• FETCH

• CLOSE

• 🎯 Severity: Warning

12. Unused Level 88 Conditions

Detects level 88 condition names that are declared but never used in the code.

• ✅ Quick Fix: Delete line or comment with asterisk
• 🎯 Severity: Warning
• 🔧 Smart Detection:
  • Validates each 88-level condition independently
  • Ignores 88-level conditions associated with FILLER variables
  • Example: 88 STATUS-OK VALUE 'Y' triggers warning if STATUS-OK is never used

Requirements

• Visual Studio Code 1.75.0 or higher
• COBOL files with extensions: .cbl, .cob, .cobol, .cpy

Settings

This extension contributes the following settings:

Validations (Enable/Disable)

Additional Options

Usage Examples

Create Constant from Hardcode

IF WS-STATUS = '00'    ⚠️ Warning: Hardcoded value

Quick Fix → Automatically generates:

01  CON-00    PIC X(02) VALUE '00'.
...
IF WS-STATUS = CON-00

Wrap DISPLAY with IF

DISPLAY 'Processing error'.    ⚠️ Warning: Unprotected DISPLAY

Quick Fix → Transforms to:

IF ${condition}
   DISPLAY 'Processing error'
END-IF.

Replace Symbolic Operators

IF WS-COUNTER > 10              ⚠️ Use 'GREATER THAN' instead of '>'

Quick Fix → Converts to:

IF WS-COUNTER GREATER THAN 10

Known Issues

• Cursor validation requires well-formatted EXEC SQL...END-EXEC blocks
• Some dynamically generated code cases may not be detected

Release Notes

1.1.0 - 2026-03-13

• Added unused level 88 condition validation
• Enhanced unused variable detection with level 88 awareness
• Improved FILLER variable handling

1.0.0 - 2026-03-11

Initial comprehensive release with:

• Unused variable validation
• Unprotected display validation
• GO TO command validation
• IF without END-IF validation
• IF without ELSE validation (optional)
• EVALUATE without WHEN OTHER validation (optional)
• Symbolic operator validation
• Hardcoded value validation
• Lowercase code validation (optional)
• File operations validation
• Cursor operations validation
• Automatic quick fixes
• Customizable settings

0.0.1

Initial beta release

Developed for mainframe COBOL development teams 🚀

Working with Markdown

You can author your README using Visual Studio Code. Here are some useful editor keyboard shortcuts:

• Split the editor (Cmd+\ on macOS or Ctrl+\ on Windows and Linux)
• Toggle preview (Shift+Cmd+V on macOS or Shift+Ctrl+V on Windows and Linux)
• Press Ctrl+Space (Windows, Linux, macOS) to see a list of Markdown snippets

For more information

• Visual Studio Code's Markdown Support
• Markdown Syntax Reference

Enjoy!