RBS, Ruby’s new type signature language

It's worth noting that while the article is coming from Square, this is an official Ruby project and is "Ruby 3’s new language for type signatures".

https://github.com/ruby/rbs

Yeah, I was wondering why this was being announced on Square's website. Seems it's because Square happens to employ Soutaro Matsumoto, who wrote the post and is also the creator of Steep[0] (an implementation of a typechecker for RBS files).

It's not clear to me whether Soutaro is a member of the Ruby core team, so it feels a bit odd that the post is written like an announcement from the Ruby maintainers.

[0] https://github.com/soutaro/steep

Soutaro is indeed a code member of the Ruby team, he also happens to work at Square. Soutaro is also one of the main contributors to RBS and helped define that standard.

He was going to keynote on this at RubyKaigi this year until it was cancelled, and had a talk at RubyConf as well on this.

Thanks for clarifying! It's great that Square is funding work like this.