| import Data.Char | |
| import Control.Applicative | |
| import Data.Maybe | |
| isbn :: String -> Bool | |
| isbn s = isValid && hasValidChecksum | |
| where | |
| isbnPattern = "D-DDD-DDDDD-X" | |
| checksum = sum . zipWith (*) [10, 9..1] . mapMaybe fromJust $ vals |
| addName counter names name = do | |
| i <- readTVar counter | |
| ns <- readTVar names | |
| orElse addName' $ return () | |
| where | |
| addName' = do | |
| guard $ any ((== name) . snd) ns | |
| writeTVar names ((i, name) : ns) | |
| writeTVar counter (i + 1) |
| (defn- valid-pattern [s] (boolean (re-matches #"\d-\d{3}-\d{5}-[\dX]" s))) | |
| (defn- valid-checksum [s] | |
| (let [csum (->> s | |
| (map {\0 0 \1 1 \2 2 \3 3 \4 4 \5 5 \6 6 \7 7 \8 8 \9 9 \X 10}) | |
| (keep identity) | |
| (map * (range 10 0 -1)) | |
| (reduce +))] | |
| (zero? (rem csum 11)))) | |
| (def isbn? (every-pred valid-pattern valid-checksum)) |
| ; type annotation, read String -> Maybe String | |
| (>fdef number [s] [string? => (? string?)]) | |
| (def number (comp second (partial re-find #"^1?([2-9]\d{2}[2-9]\d{6})$") #(str/replace % #"[\D]" ""))) |
| (>defn number | |
| "Cleans up NANP-style Phone Numbers." | |
| [s] | |
| [string? => (? string?)] | |
| (let [only-digits #(clojure.string/replace % #"[\D]" "") | |
| nanp-match #(re-find #"^1?([2-9][0-9]{2}[2-9][0-9]{6})$" %)] | |
| (->> s only-digits nanp-match second))) |
| (s/def ::phrases (s/map-of number? string?)) | |
| (def ^:private phrases {3 "Pling" 5 "Plang" 7 "Plong"}) | |
| (s/fdef raindrops | |
| :args (s/cat :n number?) | |
| :ret string?) | |
| (defn raindrops | |
| "Returns number as string unless it is divisible by 3, 5 or 7, in which case it returns | |
| the concatenation of the words Pling (3), Plang (5) and Plong (7) for the divisible cases." | |
| [n] |
| raindrops :: Int -> String | |
| raindrops n = tests id (show n) | |
| where | |
| tests = test 3 "Pling" . test 5 "Plang" . test 7 "Plong" | |
| test d s x | n `mod` d == 0 = const (s ++ x "") | |
| | otherwise = x |
| {-# LANGUAGE LambdaCase #-} | |
| data Planet = Earth | Mercury | Venus | Mars | Jupiter | Saturn | Uranus | Neptune | |
| deriving (Eq) | |
| ageOn :: Planet -> Float -> Float | |
| ageOn = flip (/) . (earthSecondsPerYear *) . earthSecondsFor | |
| where | |
| earthSecondsPerYear = 31557600 | |
| earthSeconds = |
| (ns etl.core | |
| (:require [clojure.string :as str])) | |
| (defn transform [source] | |
| (into {} | |
| (for [[score cs] source | |
| c cs] | |
| [(str/lower-case c) score]))) | |
| ;; and with macro abstractions |