lagenorhynque

user> (defn fib [n]
        (cond
          (= n 0) 0
          (= n 1) 1
          :else (+ (fib (- n 1))
                   (fib (- n 2)))))
#'user/fib
user> (map fib (range 10))
(0 1 1 2 3 5 8 13 21 34)
user> (require '[clojure.spec.alpha :as s])

lagenorhynque

{:deps {org.clojure/clojure {:mvn/version "1.9.0"}
        org.clojure/tools.cli {:mvn/version "0.3.5"}}
 :paths ["."]}

lagenorhynque

user=> (alembic.still/distill '[org.clojure/algo.generic "0.1.2"])
WARN: org.clojure/clojure version 1.4.0 requested, but 1.9.0-beta1 already on classpath.
Loaded dependencies:
[[org.clojure/algo.generic "0.1.2"]]
Dependencies not loaded due to conflict with previous jars :
[[org.clojure/clojure "1.4.0"]]
nil
user=> (require '[clojure.algo.generic.functor :as functor])
nil
user=> (functor/fmap inc {:a 1 :b 2 :c 3})

lagenorhynque

;; cf. https://github.com/ctford/traversy
user> (require '[traversy.lens :as lens])
nil
user> (def data {:a [{:aa 1 :bb 2}
                     {:cc 3}]
                 :b [{:dd 4}]})
#'user/data
user> (-> data
          (lens/update (lens/*> lens/all-values lens/each lens/all-values)
                       #(if (even? %) (inc %) %)))

lagenorhynque

lagenorhynque

λ> import Data.Ratio ((%))
-- y = e^xの区間[0,1]の面積の近似
λ> sum $ zipWith (*) (repeat 0.001) (map (\x -> exp . realToFrac $ x) [0, 1%1000..999%1000])
1.7174228307349653
-- y = x^2の区間[0,1]の面積の近似
λ> realToFrac . sum $ zipWith (*) (repeat $ 1%1000) (map (\x -> x * x) [0, 1%1000..999%1000])
0.3328335
λ>

lagenorhynque

user> (defn enum
        ([fst]
         (iterate inc fst))
        ([fst snd]
         (iterate #(+ % (- snd fst)) fst))
        ([fst snd lst]
         (range fst (inc lst) (- snd fst))))
#'user/enum
user> (take 10 (enum 1))  ; take 10 [1..]
(1 2 3 4 5 6 7 8 9 10)

lagenorhynque

;; 0 <= x <= 23
;; 0 <= y <= 23
;; x + y = 23
;; 2x + 4y = 62
user> (for [x (range (inc 23))
            y (range (inc 23))
            :when (and (= (+ x y) 23)
                       (= (+ (* 2 x) (* 4 y)) 62))]
        [x y])
([15 8])

lagenorhynque

;; cf. https://en.wikipedia.org/wiki/Leibniz_formula_for_%CF%80
user> (require '[clojure.math.numeric-tower :as math])
nil
user> (def leibniz (map / (iterate - 4) (iterate #(+ % 2) 1)))
#'user/leibniz
user> (->> leibniz
           (take-while #(> (math/abs %) 1/1000))
           (apply +)
           double)
3.141092653621043

lagenorhynque

;; cf. https://clojure.org/guides/spec
user=> (require '[clojure.spec.alpha :as s])
nil
user=> (s/def ::side-a number?)
:user/side-a
user=> (s/def ::side-b number?)
:user/side-b
user=> (s/def ::side-c number?)
:user/side-c
user=> (s/fdef cuboid-volume