Ideally, access to the existing Ruby ecosystem.

Crystal makes sense in the context of writing stuff from scratch or wanting to contribute to the ecosystem.

I sincerely doubt a tool like this will give you access to the full Ruby ecosystem.

I definitely love the idea though, I struggle with lower level languages, although I consider myself fairly decent with both Python and JavaScript.

This one in particular probably not, since it is in early stages.

RubyMotion on the contrary is quite advanced and an AOT compiler to go to, when one wants to use Ruby for mobile development.

http://www.rubymotion.com/

RubyMotion is probably as good as it gets for AOT. Ruby depends on dynamic dispatch and thankfully objc is very similar the needs of a Ruby-like language.

Truffle might work even better as it’s able to recompile.

Any C++ port will likely need to reimplement half of the objc runtime to support all of Ruby. Not sure if clangs/gcc objc support includes the runtime, but I’m imagining it would… so maybe it’s reusable that way.

Is RubyMotion something we can actually use to build non-toy apps in 2021? I thought it was dead, but perhaps it is not!

It is not dead. There are regular releases, a helpful community at slack.RubyMotion.com and training available at https://wndx.school (that last is mine)

Crystal is superficially similar but it pretty much ends there, and many off the differences feels pretty arbitrary.

> which is pretty much Ruby

Crystal looks similar, but really has very different semantics, and so can't run existing Ruby.

I was going to suggest adding Natalie to Ruby Compiler List [1], turns out Natalie is already on the list and started in 2019!

[1]https://ruby-compilers.com

Yeah I need to do the deep dive on it!

Crystal is not “pretty much Ruby” unfortunately. Use it for more than 30 seconds and you realize “oh this isn’t ruby”