wtf is asdf-ruby?

asdf-ruby is a plugin that lets you manage multiple versions of Ruby on your computer. Instead of having just one version of Ruby installed system-wide, this tool lets you switch between different Ruby versions depending on which project you're working on. It's particularly useful if you work on older projects that need an older version of Ruby, while also developing on newer projects that require the latest version. The way it works is through asdf, which is a version manager that handles many programming languages and tools. This plugin teaches asdf how to install and switch between Ruby versions specifically. When you tell it to install a particular Ruby version, it either builds Ruby from source code on your machine (which requires some system dependencies to be installed first) or, optionally, downloads a pre-built version if you've configured it to do so. Once installed, asdf keeps track of which Ruby version each of your projects should use by reading configuration files in those project directories. The plugin has some nice convenience features built in. You can automatically install a standard set of gems (Ruby packages) whenever you install a new Ruby version, just by listing them in a file. If you're switching from another Ruby version manager like RVM or Chruby, asdf-ruby can read your old configuration files to make the transition smoother. You can also apply custom patches to Ruby before building it if you need to, which is useful for specialized use cases. People who would use this are typically Ruby developers working on multiple projects with different version requirements, teams that want a standardized way to manage development environments, or anyone who has struggled with Ruby version conflicts in the past. It's designed to be a modern replacement for older Ruby version managers, with a focus on being consistent with how asdf manages other languages and tools across your system.