Shimuuar

import Debug.Trace

xs1,xs2 :: [Int]
xs1 = map (\x -> (trace "2" 2 + trace "3" 3) * x) [0..]
xs2 = map (let y = trace "2" 2 + trace "3" 3 in \x -> x*y) [0..]
{-
*Main> take 4 xs1
[2
3
0,2

Shimuuar

import Data.Monoid

-- | Type class for monoidal accumulators
class Monoid m => Accumulator m a where
  -- | Convert value to 1-element accumulator
  unit :: a -> m
  unit a = cons a mempty
  -- | Prepend value to accumulator
  cons :: a -> m -> m
  cons a m = unit a <> m

Shimuuar

{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE OverlappingInstances  #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE FunctionalDependencies #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE UndecidableInstances #-}
module Region76 where

Shimuuar

-- Trick for expressing contexts like (∀ a. Binary a => Binary (f a))
--
-- This type class says that if we have dictionary for data type `a' we can 
-- construct dictionary for `f a' or equivalently that if `a' is instance of 
-- Binary `f a' is instance too.
class Binary2 f where
  binaryDict :: BinaryDict a -> BinaryDict (f a)

data BinaryDict a where
  BinaryDict :: Binary a => BinaryDict a

Shimuuar

{-# LANGUAGE InstanceSigs #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE GADTs #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
module Sum where

import Data.Vector.Fixed (S,Z,Fun(..))
import Data.Vector.Fixed.Cont (Fn,Arity(..))

Shimuuar

{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE PolyKinds #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE KindSignatures #-}
module TySet where


type InsertRes x set = If (Member x set) set (x ': set)

Shimuuar

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

Shimuuar

import Criterion.Main   

----------------------------------------------------------------
-- Unit types

data U10 = 
     U10_01
   | U10_02
   | U10_03
   | U10_04

Shimuuar

{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE OverlappingInstances  #-}
{-# LANGUAGE GADTs         #-}
{-# LANGUAGE TypeOperators #-}


-- Type constructor for list of types which is used in tests for
-- memberhip
data a ::: b

Shimuuar

$ ghc --make foo
[1 of 1] Compiling Main             ( foo.hs, foo.o )
Linking foo ...
$ ./foo
"Starting IO"
Warning: Couldn't open "/dev/urandom"
Warning: using system clock for seed instead (quality will be lower)
"Starting IO"
foo: nonexitant: openFile: does not exist (No such file or directory)