Concise inline operations with Cascalog serfn branch

gistfile1.clj

(use 'cascalog.playground) (bootstrap)

(require '[clojure.set :as set])
(require '[cascalog.vars :as v])

(defn all-syms [form]
  (if (coll? form)
    (reduce (fn [curr elem] (set/union curr (all-syms elem)))
            #{}
            form)
  #{form}))

(defmacro imapcatop [& body]
  (let [used-vars (->> body all-syms (filter symbol?) (filter v/cascalog-var?))
        impl `(cascalog.api/mapcatop ~(vec used-vars) ~@body)]
    `(cascalog.api/predmacro [invars# outvars#]
      {:pre [(zero? (clojure.core/count invars#))]}
      [[~impl :<< ~(vec (map str used-vars)) :>> outvars#]]
      )))

(?<- (stdout) [?word ?count]
         (sentence ?sentence)
         ((imapcatop (.split ?sentence " ")) :> ?word)
         (c/count ?count))