Python Semantic Highlighter

IntelliJ-style semantic highlighting for Python in VS Code

Give each symbol a unique color based on its name — making it easy to track variables, spot patterns, and understand code flow at a glance.

🌟 Why This Extension?

✨ Features

🎨 Symbol-based Coloring

Every symbol gets a consistent, unique color based on its name:

• Same symbol = same color throughout the file
• Different symbols = visually distinct colors
• Colors persist across editing sessions

📁 Semantic Categories

Fine-tuned coloring for different Python constructs:

🎯 Smart Color Distribution

Uses the Van der Corput sequence for maximum color separation:

• Adjacent variables get maximally different colors
• No more similar-looking variables!
• Colors distributed evenly across your chosen hue range

⌨️ Keyword Colors

Fixed colors for Python keywords with full customization:

• def, class, return, yield, await, async
• if, elif, else, for, while, break, continue
• try, except, finally, raise
• import, from, as, with, lambda
• Leave empty to use your theme's default colors

🔧 Visual Settings Panel

Beautiful settings UI with:

• Circular Hue Picker — Intuitive color wheel for selecting hue ranges
• HSV Sliders — Fine-tune saturation and lightness
• Live Preview — See color gradients as you adjust
• Per-category Toggles — Enable/disable each category
• Full Range Button — Quickly set hue to 0°-360°

📓 Jupyter Notebook Support

Works seamlessly with .ipynb files:

• Highlights code in notebook cells
• Handles IPython magic commands (%matplotlib, %%time)
• Works with shell commands (!pip install)

⚡ Fast Rust-based Parser

• Native Rust binary using rustpython-parser
• Sub-millisecond parsing for most files
• Debounced updates for smooth editing
• Works in Peek Definition and split editors
• Highlights unsaved changes in real-time

📦 Installation

From VS Code Marketplace (Recommended)

1. Open VS Code
2. Go to Extensions (Cmd+Shift+X / Ctrl+Shift+X)
3. Search for "Python Semantic Highlighter"
4. Click Install

Or install directly: View on Marketplace

From GitHub Releases

1. Go to the Latest Release
2. Download python-semantic-highlighter-x.x.x.vsix
3. In VS Code: Cmd+Shift+P / Ctrl+Shift+P → Extensions: Install from VSIX...
4. Select the downloaded file

Supported Platforms

⚙️ Configuration

Open Settings Panel

The easiest way to configure:

• Command Palette: Cmd+Shift+P → Python Semantic Highlighter: Open Settings Panel
• Extension Page: Click gear icon ⚙️ → Open Settings Panel
• VS Code Settings: Search pythonSemanticHighlighter → Click link

Settings Overview

Example Configuration

{
  "pythonSemanticHighlighter.enable": true,
  "pythonSemanticHighlighter.debounceMs": 150,
  "pythonSemanticHighlighter.semanticCategories": {
    "localVariable": {
      "enabled": true,
      "hueRange": [0, 360],
      "saturation": [40, 60],
      "lightness": [55, 70]
    },
    "parameter": {
      "enabled": true,
      "hueRange": [0, 360],
      "saturation": [45, 65],
      "lightness": [55, 70]
    }
  },
  "pythonSemanticHighlighter.keywordColors": {
    "def": "#CC7832",
    "class": "#CC7832",
    "return": "#CC7832"
  }
}

🎮 Commands

🏗️ How It Works

┌─────────────────────────────────────────┐
│           Python Source Code            │
└─────────────────┬───────────────────────┘
                  │
                  ▼
┌─────────────────────────────────────────┐
│      Rust Parser (rustpython-parser)    │
│  • Parses Python AST                    │
│  • Extracts symbols with positions      │
│  • Identifies semantic categories       │
│  • Handles Jupyter magic commands       │
└─────────────────┬───────────────────────┘
                  │ JSON
                  ▼
┌─────────────────────────────────────────┐
│         VS Code Extension               │
│  • Receives symbol information          │
│  • Applies Van der Corput distribution  │
│  • Generates HSL colors per category    │
│  • Applies TextEditor decorations       │
└─────────────────────────────────────────┘

🔧 Requirements

• VS Code 1.85.0 or later
• macOS (Apple Silicon & Intel), Linux (x64/arm64), or Windows (x64)

❓ FAQ

Q: Colors aren't showing up? A: Make sure the extension is enabled in settings. Try Cmd+Shift+P → Python Semantic Highlighter: Refresh. Also try reloading the window (Developer: Reload Window).

Q: How do I use theme default colors for keywords? A: Leave the keyword color empty (don't set any value). The extension will fall back to your theme's colors.

Q: Colors are too similar? A: The Van der Corput sequence ensures maximum separation. Try using the "Full Range" button in settings to use the full 0°-360° hue range.

Q: Does it work with virtual environments? A: Yes! The extension analyzes the source code directly, no Python interpreter needed.

Q: Highlighting not updating on edits? A: The extension now highlights unsaved changes in real-time (v1.4.1+). Make sure you have the latest version installed.

🤝 Contributing

Contributions welcome! Please see the GitHub repository for guidelines.

📄 License

MIT License - see LICENSE for details.

🙏 Acknowledgments

• rustpython-parser — Python parser in Rust
• Inspired by IntelliJ IDEA's semantic highlighting feature

Enjoy coding with colors! 🌈