Complexity Hints for VS Code
A VS Code extension that displays algorithmic complexity hints (Big-O notation) directly in the editor as CodeLens annotations above C# methods.
Features
- CodeLens Complexity Hints: See time and space complexity directly above method signatures
- Confidence Indicators: Visual indicator of analysis confidence level
- Debounced Analysis: Efficient analysis that triggers after you stop typing
- Review Warnings: Methods with potential issues are flagged for human review
Requirements
- VS Code 1.74+
- Node.js 18+ (for development)
- .NET 8.0 SDK (required for the analysis backend)
- Python 3.11+ (optional, for advanced recurrence solving)
- uv 0.5+ (optional, for Python environment management)
Installation
From VSIX
- Download the
.vsix file from the releases page
- In VS Code, open the Command Palette (
Cmd+Shift+P / Ctrl+Shift+P)
- Run "Extensions: Install from VSIX..."
- Select the downloaded file
From Source
cd src/ComplexityAnalysis.IDE/vscode
npm install
npm run compile
npm run package
This creates a .vsix file that can be installed locally.
Usage
- Open a C# file in VS Code
- Wait for the extension to activate (you'll see "Complexity Hints" in the status bar)
- CodeLens annotations will appear above each method showing:
- T: Time complexity (e.g.,
O(n log n))
- S: Space complexity (e.g.,
O(n))
- Confidence score (0-100%)
Commands
| Command |
Description |
Complexity: Check Toolchain |
Verify that .NET, Python, and uv are installed |
Complexity: Analyze Current File |
Force re-analyze the current file |
Complexity: Analyze Method at Cursor |
Analyze only the method under cursor |
Complexity: Show Output |
Open the output panel for diagnostics |
Configuration
| Setting |
Default |
Description |
complexity.enableCodeLens |
true |
Enable/disable CodeLens hints |
complexity.analysisDebounceMs |
350 |
Debounce delay before triggering analysis |
complexity.dotnetPath |
"dotnet" |
Path to .NET CLI |
complexity.pythonPath |
"python3" |
Path to Python interpreter |
complexity.uvPath |
"uv" |
Path to uv package manager |
complexity.cliProjectPath |
(auto) |
Path to the CLI project for analysis |
How It Works
The extension uses a multi-stage pipeline:
- Document Change Detection: Monitors C# files for changes
- Debounced Analysis: Waits for typing to stop before analyzing
- Backend Communication: Invokes the .NET CLI tool for Roslyn-based analysis
- Result Caching: Caches results by document version to avoid re-analysis
- CodeLens Display: Shows results as CodeLens annotations
Analysis Pipeline
┌─────────────┐ ┌─────────────┐ ┌─────────────┐
│ Document │───▶│ Debouncer │───▶│ Backend │
│ Change │ │ (350ms) │ │ CLI │
└─────────────┘ └─────────────┘ └─────────────┘
│
▼
┌─────────────┐ ┌─────────────┐ ┌─────────────┐
│ CodeLens │◀───│ Result │◀───│ Roslyn │
│ Display │ │ Store │ │ Analysis │
└─────────────┘ └─────────────┘ └─────────────┘
Development
Project Structure
src/ComplexityAnalysis.IDE/
├── vscode/ # VS Code extension (TypeScript)
│ ├── src/
│ │ ├── extension.ts # Main entry point
│ │ ├── core/ # Shared utilities
│ │ ├── providers/ # CodeLens provider
│ │ └── analysis/ # Backend integration
│ ├── package.json # Extension manifest
│ └── tsconfig.json # TypeScript config
└── Cli/ # .NET CLI tool (C#)
├── Program.cs # CLI entry point
├── Commands/ # CLI commands
└── Models/ # JSON output models
Building
# Build the TypeScript extension
cd src/ComplexityAnalysis.IDE/vscode
npm install
npm run compile
# Build the .NET CLI
cd src/ComplexityAnalysis.IDE/Cli
dotnet build
# Package the extension
npm run package
Testing
# Run TypeScript tests
npm test
# Run .NET tests
dotnet test
Debugging
- Open the workspace in VS Code
- Press F5 to launch the Extension Development Host
- Open a C# file in the new window
- View logs in the "Complexity Hints" output channel
Contributing
- Fork the repository
- Create a feature branch
- Make your changes
- Run tests (
npm test and dotnet test)
- Submit a pull request
License
MIT License - see LICENSE for details.
Acknowledgments
