fmap

{-# LANGUAGE GADTs          #-}
{-# LANGUAGE DataKinds      #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE Rank2Types     #-}

-- Construct vectors of length LEQ some bound. :-)

data Natural where
  Zero :: Natural
  Succ :: Natural -> Natural

fmap

{-# LANGUAGE TemplateHaskell #-}

import Language.Haskell.TH (ExpQ, Exp(LamE, VarE, TupE), Pat(VarP), newName)

tuple :: Int -> ExpQ
tuple n = do
  x <- newName "x"
  return $ LamE [VarP x] (TupE . replicate n $ VarE x)

-- $(tuple 3) "fnord" == ("fnord","fnord","fnord")

fmap

import Control.Monad (liftM2)
import Control.Arrow (Arrow((&&&)), (>>>), (<<<))

(>>|) :: Arrow a => a b c -> a c d -> a b (c,d)
(>>|) = liftM2 (<<<) (&&&) (>>>)

fmap

allOf :: Enum a => Bounded a => [a]
allOf = [minBound..maxBound]

fmap

{-# LANGUAGE GADTs          #-}
{-# LANGUAGE DataKinds      #-}
{-# LANGUAGE KindSignatures #-}
{-# LANGUAGE TypeFamilies   #-}
{-# LANGUAGE RankNTypes     #-}

data N = Z | S N

data Vector :: * -> N -> * where
  Nil  :: Vector a 'Z

fmap

import Prelude hiding (foldr, filter)
import Data.Maybe (fromJust, isJust)
import Data.Foldable (Foldable(foldr))
import Data.HashMap.Lazy (HashMap, singleton, unionWith, foldrWithKey)
import Data.Hashable (Hashable(..))
import Data.Monoid (Monoid(mappend, mempty))
import Data.Vector (Vector, find, cons, filter)

-- sniEquivalence describes a surjective but non-injective relation between
-- {b, a}.

fmap

---
Four Postures of Death
Sidney Keyes
August 1941
---

                      I

             DEATH AND THE MAIDEN

fmap

#!/usr/bin/env runhaskell

{-# LANGUAGE DeriveDataTypeable    #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE OverloadedStrings     #-}
{-# LANGUAGE RecordWildCards       #-}
{-# LANGUAGE TemplateHaskell       #-}
{-# LANGUAGE TypeFamilies          #-}

-- # [Task:](http://functionaljobs.com/jobs/8678-haskell-developer-at-zalora)

fmap

a (m,n) | m==0        = n+1
        | m>0 && n==0 = a(m-1,1)
        | m>0 && n>0  = a(m-1,a(m,n-1))

k c n d | n == 0     = c*d
        | n == 1     = c^d
        | d == 0     = 1
        | otherwise  = k c (n-1) $ k c n (d-1)

g = (!!63) $ iterate (\ n -> k 3 n 3) 4

fmap

DATE="$1"
yymmdd() {
  date -d"$DATE" '+%Y%m%d'
};

cat <<EOF | sed 's/^ *//'
  BEGIN:VCALENDAR
  VERSION:2.0
  PRODID:-//Hack and Tell//NONSGML v1.0//EN
  BEGIN:VEVENT