Highlight Named Colors in Positron Python: Complete Guide

Positron editor doesn’t natively highlight named colors like ‘red’ in Python code by default, but you can configure this through VS Code extensions, custom syntax highlighting rules, or by modifying the editor’s token color customizations in settings.json. Since Positron is built on VS Code technology, you have access to various customization options that enable named color highlighting similar to RStudio’s functionality.

Contents

• Understanding the Current Limitation
• Using VS Code Extensions
• Custom Syntax Highlighting Configuration
• Manual Token Color Customization
• Alternative Solutions

Understanding the Current Limitation

The default Positron installation and most available extensions currently focus on hex color codes (like #FF0000) rather than named color strings (like 'red'). This limitation exists because:

1. Extension Limitations: The popular “Color Highlight” extension, as mentioned in the Stack Overflow question, successfully highlights hex codes but doesn’t recognize named color strings.

2. Language Server Protocol: Python’s language server doesn’t inherently recognize color names as special tokens, so they appear as regular string literals by default.

3. Syntax Highlighting Rules: Standard Python syntax highlighting treats color names as ordinary strings, not as special color values that deserve special visual treatment.

Using VS Code Extensions

Since Positron is based on VS Code, you can leverage extensions that provide enhanced color recognition:

1. Install Color-Specific Extensions

Several VS Code extensions work with Positron to enhance color recognition:

• Color Highlight: Already installed by default, but limited to hex codes
• Rainbow CSV: Provides syntax highlighting for CSV files with specific colors
• Custom Colorizer: Allows custom rules for syntax highlighting

According to the Andrew Heiss blog, extensions like Rainbow CSV can be extended to handle color recognition in various file types.

2. Configure Extensions for Named Colors

Some extensions can be configured to recognize named colors:

1. Open the Extensions view (Ctrl+Shift+X or Cmd+Shift+X)
2. Search for extensions with customizable syntax highlighting
3. Check if they support custom regex patterns for color names

The key is to find extensions that allow custom rule definitions or regex patterns that match Python color names.

Custom Syntax Highlighting Configuration

You can configure Positron’s syntax highlighting to recognize named colors through several methods:

1. Using settings.json Configuration

Positron supports VS Code’s editor.tokenColorCustomizations for custom syntax highlighting:

{
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "scope": "string.quoted.python",
        "settings": {
          "foreground": "#FF0000"
        }
      },
      {
        "scope": "constant.other.color.python",
        "settings": {
          "foreground": "#FF69B4"
        }
      }
    ]
  }
}

2. Creating Custom Color Rules

To specifically target named colors, you can define custom rules:

{
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "name": "Python Named Colors",
        "scope": "string.quoted.double.python",
        "settings": {
          "foreground": "#FF69B4"
        },
        "patterns": [
          {
            "include": "#python-string"
          },
          {
            "match": "\\b(red|blue|green|yellow|orange|purple|pink|brown|black|white|gray|grey)\\b",
            "captures": {
              "1": {
                "name": "constant.other.color.python"
              }
            }
          }
        ]
      }
    ]
  }
}

3. Language-Specific Customization

For Python-specific color highlighting, you can use:

{
  "[python]": {
    "editor.semanticHighlighting.enabled": true,
    "editor.tokenColorCustomizations": {
      "textMateRules": [
        {
          "scope": "support.constant.color.python",
          "settings": {
            "foreground": "#FF1493"
          }
        }
      ]
    }
  }
}

Manual Token Color Customization

For more granular control over color highlighting, you can customize token colors manually:

1. Accessing Token Customization

1. Open Settings (Ctrl+, or Cmd+,)
2. Search for “token color customization”
3. Click “Edit in settings.json”

2. Adding Custom Color Definitions

{
  "workbench.colorTheme": "Default High Contrast",
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "scope": "constant.other.color",
        "settings": {
          "foreground": "#FF6B6B"
        }
      }
    ]
  }
}

3. Creating Color-Specific Scopes

You can define custom scopes for different color categories:

{
  "editor.tokenColorCustomizations": {
    "textMateRules": [
      {
        "scope": "string.color.name.python",
        "settings": {
          "foreground": "#FF69B4",
          "fontStyle": "bold"
        }
      },
      {
        "scope": "string.color.hex.python",
        "settings": {
          "foreground": "#00CED1"
        }
      }
    ]
  }
}

Alternative Solutions

1. Using LSP Extensions

Language Server Protocol (LSP) extensions can provide enhanced color recognition:

• Python LSP Server: Supports custom semantic tokens
• Pylance: Microsoft’s Python language server with enhanced IntelliSense

2. Custom Themes

As mentioned in the Christopher T. Kenny blog, you can create custom themes that include color-specific highlighting:

{
  "workbench.colorTheme": "Custom Theme",
  "workbench.colorCustomizations": {
    "[Custom Theme]": {
      "editorTokenColorCustomizations": {
        "textMateRules": [
          {
            "scope": "constant.other.color",
            "settings": {
              "foreground": "#FF69B4"
            }
          }
        ]
      }
    }
  }
}

3. Extension Development

For advanced users, you can develop a custom VS Code extension specifically for Python color highlighting:

1. Use the VS Code Extension API
2. Define custom textMate grammars
3. Implement color name recognition patterns
4. Package and distribute the extension

4. Preprocessor Tools

Consider using preprocessor tools that convert named colors to hex codes before editing:

• Python scripts that parse files and convert color names
• Build tools that handle color name resolution
• Linting tools that detect and flag color names for review

Conclusion

Highlighting named colors in Positron for Python requires leveraging the editor’s VS Code heritage and implementing custom configurations. Here are the key takeaways:

1. Extension Approach: Install and configure VS Code extensions that support custom regex patterns for color name recognition
2. Configuration Method: Use settings.json with editor.tokenColorCustomizations to define custom syntax highlighting rules
3. Theme Customization: Create or modify themes to include color-specific highlighting scopes
4. Advanced Options: Consider developing custom extensions or using LSP servers for enhanced color recognition

The most practical solution for most users would be to configure editor.tokenColorCustomizations in settings.json with regex patterns that match common Python color names, then apply appropriate visual styling to those matches. While this doesn’t exactly replicate RStudio’s functionality, it provides a flexible and customizable alternative that works within Positron’s VS Code-based architecture.

For users working extensively with color names in Python code, developing a custom VS Code extension might be the most comprehensive solution, offering the deepest integration with the editor’s highlighting system.

Sources

1. How to highlight a named color (e.g., “red”) in editor in Positron for Python? - Stack Overflow
2. Fun with Positron | Andrew Heiss
3. Settings, Keybindings, and Extensions for Positron – Christopher T. Kenny
4. Porting my favorite RStudio color theme to Positron – %>% dreams
5. Migrating to Positron from VS Code – Positron