It's not a Ruby. It doesn't even pretend to be a Ruby. I mean, to be a Ruby, this needs to work:

    a = Object.new
    list_of_modules.each { |mod| a.extend(mod) }

Ruby cannot be separated from its dynamism and to claim it can is misleading.

OCaml (well, actually Scala in my case, but I can understand why people wouldn't want to have to use the JVM) is already that, as far as I can see. What is it that Crystal offers that OCaml doesn't?

Doesn't share the fugly OCaml syntax.

Not a great way to convince OCaml fans to use something else.

All 3 of them? Jokes aside, they're probably aiming for Ruby fans (or fans of other dynamic languages).

I doubt Crystal's marketing goals are to convince OCaml fans...

A gentle learning curve for developers with a Ruby background.

Is this the same with Crystal, as shown in Ruby:

  irb(main):001:0> "".methods.size
  => 170

  irb(main):002:0> 0.methods.size
  => 133

If it is, I mean, I don't see it being so fast.

What on earth has the size of the list of methods to do with performance?

The number of methods in the standard library really doesn't impact performance in a compiled language since you can tree shake the stuff that isn't used. And even if you don't tree shake having lots of methods isn't really a noticable performance loss in compile to binary languages since you don't need to spin up a VM