CODESYS Validator Extension

A VS Code extension for validating Structured Text (ST) IEC 61131-3 code for CODESYS 3.5.18 compatibility with native VS Code notifications.

Features

• Real-time Validation: Validates ST code on file save (configurable)

• Native Notifications: Uses VS Code's native window.showInformationMessage(), showWarningMessage(), and showErrorMessage() APIs for user feedback

• Syntax Checking: Detects common ST syntax issues including:

  • Invalid array bounds
  • Missing control structure keywords (THEN, DO, END_IF, etc.)
  • Data type mismatches
  • Variable declaration issues
  • Invalid assignment operators (= instead of :=)

• Batch Validation: Validate all ST files in workspace at once

• Detailed Messages: Shows line numbers and specific error descriptions

• Configurable: Enable/disable on-save validation and detailed messages

Commands

• CODESYS: Validate ST Code (Ctrl+Shift+K)

  • Validates the currently open ST file and shows results in a notification

• CODESYS: Validate All ST Files

  • Runs validation on all .st files in the workspace

Configuration

Add these to your VS Code settings.json:

{
  "codesysValidator.enableOnSave": true,           // Validate on save (default: true)
  "codesysValidator.showDetailedMessages": true   // Show detailed error messages (default: true)
}

Notifications Used

The extension uses the following VS Code Notification APIs:

• vscode.window.showInformationMessage() - Success messages
• vscode.window.showWarningMessage() - Issues found
• vscode.window.showErrorMessage() - (reserved for critical errors)

All notifications support:

• Modal option: Can be set for more prominent alerts
• Detail text: Provides additional information in modal messages
• Action buttons: Users can interact with notification options

Installation

1. Clone or extract this repository
2. Run npm install to install dependencies
3. Open the folder in VS Code
4. Press F5 to launch the extension in debug mode
5. Package with vsce package to create a .vsix file

Development

• Compile: npm run compile
• Watch: npm run watch
• Test: npm test
• Lint: npm run lint

Project Structure

.
├── src/
│   ├── extension.ts       # Main extension entry point
│   └── validator.ts       # CODESYS ST validation logic
├── .vscode/
│   ├── launch.json        # Debug configuration
│   └── tasks.json         # Build tasks
├── package.json           # Extension metadata and dependencies
└── tsconfig.json          # TypeScript configuration

How It Works

1. Activation: Extension activates when opening ST files or on workspace open
2. Validation: Simulates CODESYS 3.5.18 compilation rules
3. Notifications: Issues found are reported via VS Code native notification APIs
4. Options: Modal messages show detailed error information with line numbers

Example Issues Detected

• ❌ ARRAY[5..0] OF INT → "Array bounds invalid: start index greater than end index"
• ❌ IF condition DO → "IF statement missing THEN keyword"
• ❌ variable = value → "ST uses := for assignment, not ="
• ⚠️ value : REAL := 42 → "REAL literal should have decimal point (e.g., 42.0)"

License

MIT