Re: your [1], Clojure's threading macros came to mind first for me as well.

    (->> 
      [(range 20 31) (range 490 501) (range 8120 8131)]
      (apply concat)
      (map classify)
      (reduce getCounts [0 0 0]))

Expands as follows:

    user> (macroexpand
           '(->> 
             [(range 20 31) (range 490 501) (range 8120 8131)]
             (apply concat)
             (map classify)
             (reduce getCounts [0 0 0])))
    (reduce
     getCounts
     [0 0 0]
     (map classify (apply concat [(range 20 31) (range 490 501) (range 8120 8131)])))

Now that you mention concurrency and flow-control in the context of these macros, it seems a little weird to me that we have "threading macros" that really are about weaving expressions together rather than concurrency/threading.