That strikes me as spectacularly unlikely. JRuby and MacRuby aren't in competition; they meet different needs and have very different usage scenarios.
There's no challenge or threat. Ruby interpreters are not a There-Can-Be-Only-One Highlander scenario. You more or less have to be trying to imagine the most wildly cartoonish and improbably malicious motives to think otherwise.
There's no challenge or threat. Ruby interpreters are not a There-Can-Be-Only-One Highlander scenario. You more or less have to be trying to imagine the most wildly cartoonish and improbably malicious motives to think otherwise.