A Ruby-based regular expression editor.

Inspired by: https://rubular.com

• Ruby 3.3

  Ruby 3.4 causes runtime issues in WebAssembly builds due to missing bigdecimal support when used as a gem,
  as described in wasmify-rails Issue #7.
  We use Ruby 3.3 as a stable fallback until full 3.4 support is confirmed.

• Ruby on Rails 8.0

  Rails 8.1 currently triggers build failures of the json gem’s native extension in wasmify-rails.
  We remain on Rails 8.0 for stability until a compatible wasmify-rails release or workaround is available, as discussed in wasmify-rails Issue #9.

• Regexp::Parser a regular expression parser library for Ruby

• Hotwire for building the frontend without using much JavaScript by sending HTML instead of JSON over the wire
• TailwindCSS to not have to write CSS at all
• RailroadDiagrams a tiny Ruby+SVG library for drawing railroad syntax diagrams like JSON.org

• Foreman for jsbundling-rails, cssbundling-rails
• Lefthook Fast and powerful Git hooks manager for any type of projects

• Rubocop the Ruby Linter/Formatter that Serves and Protects
• ERB Lint Lint your ERB or HTML files
• Biome Format, lint, and more in a fraction of a second
• RSpec for Ruby testing
• Playwright for E2E testing
• Octocov octocov is a toolkit for collecting code metrics

• Wasmify Rails — Build Rails apps into WebAssembly so the application can run in the browser
• GitHub Pages — Host the generated static site (Wasm bundles and assets) as the deployment target

• Dependabot automated dependency updates built into GitHub
• Gitleaks Find secrets with Gitleaks
• Brakeman a static analysis security vulnerability scanner for Ruby on Rails applications

• GitHub Actions for testing, linting, and building web application and deploy to GitHub Pages

1. Clone the repo locally:

git clone https://github.com/aim2bpg/rubree.git
cd rubree

2. Install gem and NPM packages and start the application locally:

bin/setup

3. Then open http://localhost:3000 in your browser.

4. (Optional) Install lefthook:

brew install lefthook
lefthook install

5. (Optional) Install gitleaks for lefthook:

brew install gitleaks

Rubocop:

bin/rubocop

ERB Lint:

bin/erb_lint --lint-all

Biome Lint:

bin/yarn biome check

Brakeman (security scan):

bin/brakeman --no-pager --skip-files app/assets/builds/,build/,node_modules/,pwa/,rubies/

Rubocop:

bin/rubocop -a

ERB Lint:

bin/erb_lint --lint-all -a

Biome Lint:

bin/yarn biome check --write
bin/yarn biome migrate --write

Run tests with the default Playwright (Chromium, headless) driver:

bin/rspec

Run tests with a specific driver by setting the DRIVER environment variable:

# Playwright - Chromium (with browser UI)
DRIVER=playwright_chromium bin/rspec

# Playwright - Chromium (headless)
DRIVER=playwright_chromium_headless bin/rspec

# Playwright - Firefox (with browser UI)
DRIVER=playwright_firefox bin/rspec

# Playwright - Firefox (headless)
DRIVER=playwright_firefox_headless bin/rspec

# Playwright - WebKit (with browser UI)
DRIVER=playwright_webkit bin/rspec

# Playwright - WebKit (headless)
DRIVER=playwright_webkit_headless bin/rspec

# Selenium - Chrome (with browser UI)
DRIVER=selenium_chrome bin/rspec

# Selenium - Chrome (headless)
DRIVER=selenium_chrome_headless bin/rspec

# Rack Test (no JS support)
DRIVER=rack_test bin/rspec

• References
  • Wasmify Rails
  • Ruby on Rails on WebAssembly, the full-stack in-browser journey

• Basic Match Handling: Provides functionality to match regular expressions against test strings.
• Match Positions: Supports the extraction and display of match start and end positions.
• Capture Groups: Extracts and displays capture groups from regex matches.
• Named Captures: Supports capturing named groups from regex matches.
• Regex Quick Reference: Provides a concise list of commonly used regex syntax for quick reference.
• Regex Examples: Interactive examples to test and visualize regex patterns in real-time.
• Execution Time Measurement: Measures and reports the execution time of regex operations.
• Regex Diagram Generation: Generates and visualizes regex patterns using SVG diagrams.
• Regex Substitution Function: Supports regex-based string substitution.
• Ruby Code Snippet Generation: Automatically generates Ruby code snippets for testing regex patterns.
• Web Interface for Regex Testing: Interactive web UI to test and visualize regular expressions in real-time.
• Permalink / Shareable URL generation: Create shareable URLs that encode the editor state (regex, sample text, and options) for easy reproduction.
• ReDoS Check Integration: Check regular expressions for ReDoS vulnerabilities via embedded recheck Playground with one-click pattern copying. (#306)

• Alternation: a\|b\|c

• Anchors: \A, ^, \b

• Character Classes: [abc], [^\\], [a-d&&aeiou]

• Character Types: \d, \H, \s

• Cluster Types: \R, \X

• Conditional Expressions: (?(cond)yes-subexp), (?(cond)yes-subexp\|no-subexp)

• Escape Sequences: \t, \\+, \?

• Free Space: whitespace and # Comments (x modifier)

• Grouped Expressions:

  • Assertions:
    • Lookahead: (?=abc)
    • Negative Lookahead: (?!abc)
    • Lookbehind: (?<=abc)
    • Negative Lookbehind: (?<!abc)
  • Atomic: (?>abc)
  • Absence: (?~abc)

• Back-references:

  • Named: \k<name>
  • Nest Level: \k<n-1>
  • Numbered: \k<1>
  • Relative: \k<-2>
  • Traditional: \1 through \9

• Capturing: (abc)

• Comments: (?# comment text)

• Named Captures: (?<name>abc), (?'name'abc)

• Options: (?mi-x:abc), (?a:\s\w+), (?i)

• Passive Captures: (?:abc)

• Subexpression Calls: \g<name>, \g<1>

• Keep: \K, (ab\Kc\|d\Ke)f

• Literals (utf-8):

  • Ruby, ルビー, روبي

• POSIX Classes:

  • [:alpha:], [:^digit:]

• Quantifiers:

  • Greedy: ?, *, +, {m,M}
  • Reluctant (Lazy): ??, *?, +?
  • Possessive: ?+, *+, ++

• String Escapes:

  • Control: \C-C, \cD
  • Hex: \x20, \xE2\x82\xAC
  • Meta: \M-c, \M-\C-C, \M-\cC, \C-\M-C, \c\M-C
  • Octal: \0, \01, \012
  • Unicode: \uHHHH, \u{H+ H+}

• Unicode Properties (Unicode 15.0.0):

  • Age: \p{Age=5.2}, \P{age=7.0}, \p{^age=8.0}
  • Blocks: \p{InArmenian}, \P{InKhmer}, \p{^InThai}
  • Classes: \p{Alpha}, \P{Space}, \p{^Alnum}
  • Derived: \p{Math}, \P{Lowercase}, \p{^Cased}
  • General Categories: \p{Lu}, \P{Cs}, \p{^sc}
  • Scripts: \p{Arabic}, \P{Hiragana}, \p{^Greek}
  • Simple: \p{Dash}, \p{Extender}, \p{^Hyphen}

For more detailed information about supported syntax, refer to the official documentation: Supported Syntax - Regexp::Parser GitHub README

Bug reports and pull requests are welcome on GitHub at https://github.com/aim2bpg/rubree

This project is licensed under the MIT License, see the LICENSE file for details

• X (Twitter) — Launch announcement

  • https://x.com/aim2bpg/status/1992926501482983803

• はてなブログ — (2025-11-24)

  • https://aim2bpg.hatenablog.com/entry/2025/11/25/083000

• Qiita — Rubular を現代化した正規表現エディタ「Rubree」をリリースしました (2025-11-24)

  • https://qiita.com/aim2bpg/items/3190cf503456f231b78b

• DEV.to — Rubree: A Modern Ruby Regex Editor Running Fully in Your Browser (2025-11-24)

  • https://dev.to/aim2bpg/rubree-a-modern-ruby-regex-editor-running-fully-in-your-browser-5g2b