[pkd]

I think this is just the usual lack of familiarity that you'll encounter with any language that has any non-C-like syntax.

The do...end bits are "blocks" and are the most powerful feature in Ruby, not just because of what they do but also because how they do it. Similarly for other comments.

When I first looked at Rust code it looked weird to me too but once you are familiar with the language a little bit it makes sense. The only thing special about Ruby here is that it allows you to be very terse.