I'm not a MacRuby or ObjC expert, but here is my understanding.
What are the advantages of MacRuby over Objective-C?
MacRuby is a variant of Ruby, so it's an interpreted, concise, dynamic language. Objective-C is a compiled language based on C (with a lot of run-time support). So, a MacRuby program will generally be shorter than the corresponding Objective-C program and may be able to do tricks (eg, using metaprogramming) that the ObjC program cannot. That said, an Objective-C program can do anything that a MacRuby program can, though generally with quite a bit more code.
What are the advantage of O-C over Ruby?
MacRuby has JIT (Just In Time compilation), so it will speed up over time. ObjC is a compiled language, so it runs fast from the beginning.
Is Xcode's support for O-C significantly better than its handling of Ruby? Do I care?
Sorry, I don't know.
At this point I'm primarily interested in OS X development, but iOS clearly needs to run a close second. What's the current status of Ruby development for iOS and is it likely to go anywhere in the nearish future?
Ruby expects a garbage collector to be available. iOS does not supply one, so that's currently a show-stopper.
Any thoughts on the longer-term prospects of either language?
ObjC is only used (to a first approximation) by Apple and folks who are programming for Apple environments. Ruby is a popular web development language and it can also be used for general scripting. I don't see either language going away any time soon, but Ruby is a more portable job skill: there are lots of companies who who hire Ruby programmers; there are far fewer companies who hire ObjC programmers. -r -- http://www.cfcl.com/rdm Rich Morin http://www.cfcl.com/rdm/resume rdm@cfcl.com http://www.cfcl.com/rdm/weblog +1 650-873-7841 Software system design, development, and documentation