💎 Ast::Template
if ci_badges.map(&:color).detect { it != "green"} ☝️ let me know on Discord or RubyForum, as I may have missed the notification.
if ci_badges.map(&:color).all? { it == "green"} 👇️ send money so I can do more of this. FLOSS maintenance is now my full-time job.
👣 How will this project approach the September 2025 hostile takeover of RubyGems? 🚑️
I've summarized my thoughts in this blog post.
🌻 Synopsis 
ast-template applies StructuredMerge templates to package directories. It plans template entries, runs package-directory sessions, preserves destination-owned README sections, and reports convergence without requiring callers to wire the lower-level merge primitives by hand.
Key Features
- Template tree planning and application.
- Package-directory session requests and reports.
- README section replacement through structured Markdown owners.
- Adapter-family registry checks for template applicability.
- Dry-run and apply workflows for repeatable template updates.
💡 Info you can shake a stick at
| Tokens to Remember |   |
|---|---|
| Works with MRI Ruby 4 |  |
| Support & Community |      |
| Source |     |
| Documentation |      |
| Compliance |      |
| Style |     |
| Maintainer 🎖️ |      |
... 💖 |
    🧊 🐙 🛖 🧪 |
Compatibility
Compatible with MRI Ruby 4.0.0+, and concordant releases of JRuby, and TruffleRuby.
CI workflows and Appraisals are generated for MRI Ruby 4.0.0+.
This test floor is configured by ruby.test_minimum in .kettle-jem.yml and
may be higher than the gem's runtime compatibility floor when legacy Rubies are
not practical for the current toolchain.
The amazing test matrix is powered by the kettle-dev stack.
How kettle-dev manages complexity in tests
| Gem | Source | Role | Total downloads |
|---|---|---|---|
| appraisal2 | GitHub | multi-dependency Appraisal matrix generation |  |
| appraisal2-rubocop | GitHub | RuboCop Appraisal generator integration |  |
| kettle-dev | GitHub | development, release, and CI workflow tooling |  |
| kettle-jem | GitHub | Appraisals & CI workflow templates |  |
| kettle-soup-cover | GitHub | SimpleCov coverage policy and reporting |  |
| kettle-test | GitHub | standard test runner and coverage harness |  |
| rubocop-lts | GitHub | Ruby-version-aware linting |  |
| turbo_tests2 | GitHub | parallel test execution |  |
✨ Installation
Install the gem and add to the application's Gemfile by executing:
bundle add ast-template
If bundler is not being used to manage dependencies, install the gem by executing:
gem install ast-template
⚙️ Configuration
Configure ast-template with a template root, a destination root, and optional session options that control dry-run behavior, adapter selection, and report detail.
Template-specific package facts are normally supplied by the caller that owns the package metadata. For Ruby gems, kettle-jem is that caller.
🔧 Basic Usage
require "ast/template"
request = Ast::Template.package_directory_session_request(
template_root: "template",
destination_root: ".",
mode: "plan",
)
report = Ast::Template.run_package_directory_session(request)
puts report.fetch(:mode)
🔐 Security
See SECURITY.md.
🤝 Contributing
If you need some ideas of where to help, you could work on adding more code coverage, or if it is already 💯 (see below) check issues or PRs, or use the gem and think about how it could be better.
We so if you make changes, remember to update it.
See CONTRIBUTING.md for more detailed instructions.
Code Coverage
Coverage service badges
📌 Versioning
This library follows for its public API where practical.
For most applications, prefer the Pessimistic Version Constraint with two digits of precision.
For example:
spec.add_dependency("ast-template", "~> 7.0")
📌 Is "Platform Support" part of the public API? More details inside.
Dropping support for a platform can be a breaking change for affected users. If a release changes supported platforms, it should be called out clearly in the changelog and versioned with that impact in mind.
To get a better understanding of how SemVer is intended to work over a project's lifetime, read this article from the creator of SemVer:
See CHANGELOG.md for a list of releases.
📄 License
The gem is available under the following licenses: AGPL-3.0-only, PolyForm-Small-Business-1.0.0. See LICENSE.md for details.
If none of the available licenses suit your use case, please contact us to discuss a custom commercial license.