Chameleon Selection

Chameleon Selection is a powerful Visual Studio Code extension designed to supercharge how you select multiple lines of text. By introducing a Domain-Specific Language (DSL) for text selection, it allows developers to quickly combine mathematical ranges, text filters, and sequence modifiers to perform complex line selections in record time.

✨ Features

• Domain-Specific Language (DSL): A rich, intuitive syntax combining mathematical intervals, CSS-like selectors, and regular expressions.
• Live Preview: See the lines that match your query highlighted in real-time as you type.
• Interactive Commands: Filter existing selections, add to them, or remove from them interactively.
• Real-time Validation: Get instant feedback if your DSL syntax is incomplete or invalid.

🚀 Getting Started

All Chameleon Selection commands are available through the VSCode Command Palette (Ctrl+Shift+P or Cmd+Shift+P on macOS).

1. Open the Command Palette.
2. Type Chameleon to see all available commands.
3. Select Chameleon: Select Lines by Query... (or use the suggested shortcut Ctrl+Shift+L / Cmd+Shift+L).
4. Enter your DSL expression in the input box and watch the live preview highlight your matching lines.
5. Press Enter to confirm the selection.

🧠 The Selection DSL

The core of Chameleon Selection is its DSL. It's designed to be intuitive and based on standards you already use daily.

1. Ranges and Intervals

Select lines based on mathematical interval notation.

• [7, 12] or [7-12]: From line 7 to 12 (inclusive).
• (7, 12]: From line 8 to 12 (7 is exclusive).
• [7, 12): From line 7 to 11 (12 is exclusive).
• (7, 12): From line 8 to 11 (both exclusive).
• [7, ] or [7-]: From line 7 to the end of the document.
• [, 12] or [-12]: From the beginning to line 12.
• 15: Only line 15.
• * or all: All lines in the document.

(Optional slicing like Python: [10-20:2] may also be supported for step-based ranges).

2. Content Search

Filter lines based on the text they contain.

• "text" or 'text': Select lines containing this exact string.
• /regex/: Select lines matching a regular expression. Supports flags like /error/i for case-insensitive search.

Tip: Use a backslash \ to escape characters, e.g., "class=\"active\"" or /path\/relative/.

3. Sequence Modifiers

Select lines based on periodicity (inspired by CSS nth-child).

• even: Selects even lines.
• odd: Selects odd lines.
• nth(3): Every 3 lines (1, 4, 7, 10...).
• nth(3, 2): Every 3 lines starting with an offset of 2 (2, 5, 8...).

4. Composition and Logical Operators

Combine different filters and ranges to create highly specific selections.

Precedence Rule: Intersection (&) and Exclusion (-) are evaluated before Union (|), following standard mathematical precedence. Use parentheses () to override.

• Union (OR) | or ,: Combines sets of lines.
  • Example: [1-5], [10-15] (Lines 1 to 5 AND 10 to 15).
• Intersection (AND) &: Lines that meet all conditions.
  • Example: [10-50] & /TODO/ (Lines between 10 and 50 that contain "TODO").
• Exclusion (NOT) - or !: Removes lines from the set.
  • Example: * - /console\.log/ (The entire document except lines with console.log).
• Grouping (): Controls evaluation order.
  • Example: ([1-100] | [200-300]) & /error/ (Lines 1-100 or 200-300 that also contain "error").

🛠️ Extension Commands

📖 Recipe Book & Use Cases

Here are some practical examples to get you started quickly:

🧹 Code Cleanup

Scenario: You want to remove all console.log statements from your file.

• Query: /console\.log/
• Action: Run Select Lines by Query, then press Delete.

Scenario: You want to find all TODO comments but only in the first 200 lines.

• Query: [-200] & /TODO/

🔍 Log Analysis

Scenario: You have a massive log file and only want to keep lines containing "ERROR", but you want to ignore "DEBUG" and "INFO".

• Query: /ERROR/ | "Exception" (Select lines with ERROR or Exception)
• Alternative: * - /DEBUG/ - /INFO/ (Select everything EXCEPT debug and info lines)

📊 Data Processing (CSV / JSON)

Scenario: You have a CSV file and want to select every other line to split the dataset in half.

• Query: even or nth(2)

Scenario: You want to extract all JSON objects that have an "id" field in lines 50 to 150.

• Query: [50-150] & /"id":/

✂️ Precision Editing

Scenario: You are refactoring a CSS file and want to find all .button classes, but ignore .button-primary.

• Query: /\.button/ - /\.button-primary/

Scenario: You want to modify imports at the top of your file (lines 1-20) and exports at the bottom (lines 300+), but nothing in between.

• Query: [-20], [300-]

⚖️ License & Legal

Ownership

This extension and its source code are the exclusive intellectual property of Juan Manuel Santoyo Ruiz. All rights reserved.

Permitted Use

You are granted a limited right to install and execute this extension within your development environment. You may not decompile, reverse-engineer, modify, or redistribute this software or any portion of its code.

Limitation of Liability

[!IMPORTANT] The software is provided "as is", without warranty of any kind. The author shall not be held responsible for any errors, data loss, or any other issues that this extension may cause in the user's development environment. In no event shall the author be liable for any claim, damages, or other liability arising from the use of this software.

© 2026 Juan Manuel Santoyo Ruiz. All rights reserved.