I feel like his reduce-true could be implemented with take-while and reductions, but my Clojure isn't strong enough to produce it. (last (take-while identity (r

I feel like his reduce-true could be implemented with take-while and reductions, but my Clojure isn't strong enough to produce it. (last (take-while identity (reductions f ns)))) is close, but we need to take one more element than take-while does.