From: Charles Oliver Nutter <charles.nutter@...>
Date: 2008-07-30T15:58:24+09:00
Subject: [ruby-core:18027] Re: RUBY_ENGINE?

Vladimir Sizikov wrote:
> In short, unsuccessfull require doesn't mean we're not on JRuby, and
> successful require doesn't mean that either. Granted, users might
> figure out the current Ruby implementation one way or another, but
> they will be not precise ways.

And another reason: ideally people could eventually be able to share gem 
repositories, with both JRuby and Ruby gems available. So this might not 
fail with a load error, it might fail with some other error because Java 
isn't present for normal Ruby.

Or we could have a single check for RUBY_ENGINE and be done with it.

- Charlie