I think this is a GREAT thing for other implementations like JRuby. Rusty Ruby would be able to learn from some of the implementation tricks that impls like Jruby and rbx have learned along the way, and maybe those guys will learn something from the Rusty Ruby crew along the way also.
Rust as far I know (not at all, honestly) doesn't interface with Java that well, so for JVM projects, it's nice to have a familiar language like Ruby that can tie in and make prototyping way easier.
I think people misunderstand how awesome Jruby is, because Ruby has never performed that well and Jruby has performed very well. Performance is not the only reason to both implementing a language. There's also the issue of mindshare, where a large group of people might already know Ruby, and it'd be easier in those scenarios to just give them Jruby and let them go to town than try and drag them through learning Java.
Rusty Ruby will do the same thing for Rust, I think. Rust is a very intricate, well-thought-out language, and I think it would benefit a lot from playing off the shared knowledge of thousands of Ruby users.
Rust as far I know (not at all, honestly) doesn't interface with Java that well, so for JVM projects, it's nice to have a familiar language like Ruby that can tie in and make prototyping way easier.
I think people misunderstand how awesome Jruby is, because Ruby has never performed that well and Jruby has performed very well. Performance is not the only reason to both implementing a language. There's also the issue of mindshare, where a large group of people might already know Ruby, and it'd be easier in those scenarios to just give them Jruby and let them go to town than try and drag them through learning Java.
Rusty Ruby will do the same thing for Rust, I think. Rust is a very intricate, well-thought-out language, and I think it would benefit a lot from playing off the shared knowledge of thousands of Ruby users.