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(defn frequencies-by
  "Returns a map from distinct results of (f item) in coll 
  to a vector duple of all (k item) (if k is provided, or items otherwise) 
  with the same (f item) value, and the number of times (f item) appears.
"
  ([f coll] 
   (frequencies-by f nil coll))
  ([f k coll] 
   (persistent! ;; copied from clojure.core

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(defn slow-assoc [m & [k v & kvs :as dat]]
  (if (empty? dat)
    m
    (apply slow-assoc (assoc m k v) kvs)))

(defn emit-assoc [ [ksym vsym]]
  `(assoc  ~ksym ~vsym))

(defmacro fast-assoc [msym & kvsyms]
  (let [assocs (map #(emit-assoc %) 

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(defn monoid* [init body]
  `(fn f# 
     ([] 
      (fn [& ~'xs] ~init))
     ([~'r] 
      (fn [& ~'xs] (~body (apply ~'r ~'xs))))
     ([~'r1 ~'r2] 
      (fn [& ~'xs] (~body(apply ~'r1 ~'xs) (apply ~'r2 ~'xs))))
     ([~'r1 ~'r2 & ~'rs]
      (fn [& ~'xs] 

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(defn lazify [[x & xs :as coll]]
  (lazy-seq
   (when (seq coll)
     (cons x (lazify xs)))))

(def my-lazy-input (lazify [1 2 4 1 2 3 1]))
(type my-lazy-input)  ;; => clojure.lang.LazySeq
(type (rest my-lazy-input)) ;; => clojure.lang.LazySeq

;; So my-lazy-input is truly lazy all the wal...Now I want to feed it to 'sequence 

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;; see 
;; https://gist.github.com/ericnormand/81722b80fc7d0b2972fda68652489f65
(ns my-ns-test
  (:require [my-ns :as sut] 
            [clojure.test.check.properties :as prop]
            [clojure.test.check.generators :as gen]
            [clojure.test.check.clojure-test :refer [defspec]]))

(let [alias-str "sut"
      sym (symbol (str alias-str "/parallel?"))]

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(ns cond-let)
;; (cond-let 
;;   (odd? x) [x n] (inc x)  
;;   (< n 10) [y (inc n)] 10
;;   :else n))

;; we want the above to yield
;; (let [x n]
;;   (if (odd? x)
;;      (inc x)

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(require '[clojure.core.async :as async :refer [chan <!! put!]])

(defn save-to [c save-f]
  (fn [rf] 
    (fn
      ([] (rf))
      ([acc] (rf acc))
      ([acc x]
       (put! c (save-f x))
       (rf acc x)))))

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(ns scratch.transducer
  (:refer-clojure :exclude [comp map filter mapcat take drop 
                            take-while drop-while
                            dedupe
                            distinct
                            reductions
                            ;; sequence
                            transduce]))

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(ns hellospec.fizzbuzz
  (:require [clojure.spec :as s]
            [clojure.spec.test :as stest]
            ;; to accomodate KLIPSE:
            ;; "[...]cljs.spec.gen.frequency is undefined[...]"
            #?(:clj [clojure.spec.gen :as gen]
               :cljs [clojure.test.check.generators :as gen])))

;; A fizzbuzz which doesn't use condition checking/branching
(defn fizzbuzz 

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(require '[clojure.spec :as s]
         '[clojure.spec.test :as stest])
               
(defn fizzbuzz 
  ([m1 m2 n]
   (let [ c #(->> % vector (concat (-> %2 dec (repeat nil))) cycle)
         fb-re #"Fizz|Buzz|FizzBuzz"]
     (->> [(c "Fizz" m1), (c "Buzz" m2)]
          (apply map 
                 (fn [i m1 m2]