Ruby 2.0

Ruby 2.0.0 shipped on February 24, 2013, exactly twenty years to the day after Yukihiro "Matz" Matsumoto picked the name “Ruby” in a 1993 chat (Ruby was named before it existed), so it doubled as the language’s twentieth-birthday release. Its headline additions were keyword arguments (naming a method’s arguments when you call it, like render(status: 200), instead of relying on their order) and refinements (a safer, scoped way to add or change methods on an existing class so the change only applies where you switch it on, rather than everywhere at once). Refinements shipped as experimental.

A deliberate goal this time was staying easy to upgrade to. Coming off the disruptive Ruby 1.9 transition, the team designed 2.0 to stay close to 1.9, writing that “it will be easier to migrate from 1.9 to 2.0 than it was from 1.8 to 1.9,” and noting that applications like Rails were already reported working on the release candidate.

Related: Ruby was named before it existed · Ruby 1.9 · Yukihiro "Matz" Matsumoto