mark from from plumbing.core

unchunk.clj

(defn unchunk
  "Takes a seqable and returns a lazy sequence that
   is maximally lazy and doesn't realize elements due to either
   chunking or apply.

   Useful when you don't want chunking, for instance,
   (first awesome-website? (map slurp +a-bunch-of-urls+))
   may slurp up to 31 unneed webpages, wherease
   (first awesome-website? (map slurp (unchunk +a-bunch-of-urls+)))
   is guaranteed to stop slurping after the first awesome website.

  Taken from http://stackoverflow.com/questions/3407876/how-do-i-avoid-clojures-chunking-behavior-for-lazy-seqs-that-i-want-to-short-ci"
  [s]
  (when (seq s)
    (cons (first s)
          (lazy-seq (unchunk (rest s))))))