hyone

# Greed is a dice game where you roll up to five dice to accumulate
# points.  The following "score" function will be used to calculate the
# score of a single roll of the dice.
#
# A greed roll is scored as follows:
#
# * A set of three ones is 1000 points
#
# * A set of three numbers (other than ones) is worth 100 times the
#   number. (e.g. three fives is 500 points).

hyone

{-# LANGUAGE FlexibleContexts #-}

import Control.Monad.List
import Control.Monad.Trans (lift)
import Control.Monad.Writer

splites :: Int -> [(Int, Int)]
splites n = [ (x, n - x) | x <- [1..n-1] ]

liftList :: Monad m => [a] -> ListT m a

hyone

{-# LANGUAGE ConstraintKinds #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}

module HList where

hyone

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE ScopedTypeVariables #-}


-- | Example code to implement instances for Singlton types introduced GHC 7.6.1

hyone

-- Run on GHC 7.6.1

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE FlexibleContexts #-}

hyone

-- $ ghci
-- GHCi, version 7.6.1: http://www.haskell.org/ghc/  :? for help
ghci> import GHC.TypeLits
ghci> :set -XDataKinds 
ghci> :set -XPolyKinds 
ghci> :set -XGADTs 
ghci> data EqRefl a b where { Refl :: EqRefl a a }

ghci> :t Refl :: EqRefl 1 1
Refl :: EqRefl 1 1 :: EqRefl Nat 1 1

hyone

-- Run on GHC 7.4.2

{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverlappingInstances #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE ScopedTypeVariables #-}

hyone

{-# LANGUAGE GADTs #-}

data Nil
data Cons

data StrongList x tag where
  Nil :: StrongList a Nil
  Cons :: a -> StrongList a b -> StrongList a Cons

safeHead :: StrongList x Cons -> x

hyone

{-# LANGUAGE GADTs #-}

data MyString
data MyInt
data MyNil

data MyData tag where
  MyString :: String -> MyData MyString
  MyInt :: Int -> MyData MyInt
  MyNil :: MyData MyNil

hyone

splites :: Int -> [(Int, Int)]
splites n = [ (x, n - x) | x <- [1..n-1] ]

count :: Int -> Int
count 1 = 1
count n = sum $ do
  (i, j) <- splites n
  return $ count i * count j