[andrewl-hn]

Wow! I'll try to count.

- 2 Rubinius attempts (Gnu Lightning and LLVM)

- MacRuby

- JRuby (do you count InDy separately?)

- IronRuby (do you count DLR separately? They didn't start with DLR, as far as I recall)

- MagLev - I think they hoped to GemStone would JIT user's Ruby code with bits of interpreter.

- TruffleRuby

- RubyOMR

- Vladimir's MJIT

- Koichi's MJIT

- YJIT

Do we count HotRuby and Opal? - both compile to JS.

I miss a few.

EDIT: mRuby, duh

[vidarh]

A few AOT attempts as well, including mine (I've hardly touched mine in the last couple of years, but I have a bunch of GC improvements that haven't been pushed to GitHub that brings it close to self-compiling, but still huge gaps - e.g. no float or regex support, no exceptions)

[andrewl-hn]

Adding a few more:

- DragonRuby - I don't know if it should count separately form MacRuby

- There were at least 5 Ruby-to-JavaScript compilers I remember from about 10 years ago, but they are very hard to find. Surprisingly, one of them - ruby2js - is still alive and actively developed!

[Mikeb85]

DragonRuby's just mRuby scripting a framework written in C.

[pjmlp]

RubyMotion, the compiler created after MacRuby's creator left Apple.