Book: Crystal Programming
forum.crystal-lang.org
forum.crystal-lang.org
How much is Ruby knowledge assumed though? I was very interested in Crystal, but was put off by how much of the learning material was written as a sort of diff against the way Ruby does things - implicitly assuming that we know Ruby and only mentioning things that differ from it. I understand that's probably an important audience for Crystal, so perhaps there should explicitly be two versions of the learning resources - one for those who know Ruby and just want the differences, and one for those who want to learn Crystal as a fresh new language of its own.
It doesn't cover the absolute basics of programming, but the only references to Ruby are mainly in the introduction. It's written from the viewpoint of someone learning Crystal, so you should have no problem following along, even without Ruby experience.