Transpiling is a source-to-source compiling. Why might we need it in Ruby? Compatibility and experiments. Ruby is evolving fast nowadays. The latest MRI release introduced, for example, the pattern-matching syntax. Unfortunately, not everyone is ready to use it yet: gems authors have to support older versions, and Ruby implementations are lagging. And it’s still experimental, which raises the question: how to evaluate proposals? By backporting them to older Rubies! I want to discuss these problems and share the story of the Ruby transpiler—Ruby Next. a decent amount of Ruby hackery is guaranteed.