I don't know why you are getting down voted - the example of Crystal running an existing Ruby file makes it looks like it could be a compiler for unmodified Ruby files. It isn't - it's a separate language - but at first glance that might not be clear.
Cython looks like typed Python. Crystal looks like typed Ruby. Both are compiled, and both are not quite as fast as C, but much faster than the language they're based off of. The point of both is to be able to write something that looks like a clean scripting language while getting close to the speed of C. Was that unclear, or are you just trolling?
