%token
  ...
  ...
  natType  { (TokenAnIdent "Nat", _)   }
  boolType { (TokenAnIdent "Bool", _)  }
  ident    { (TokenAnIdent $$, _)      }

%token
  ...
  ident    { (TokenAnIdent $$, _)      }
  ...
  natType  { (TokenAnIdent "Nat", _)   }
  boolType { (TokenAnIdent "Bool", _)  }

f :: forall a b. Eq b => (a -> b) -> (a -> b) -> a -> Bool

-- >>> :{
-- >>> let result = "good"
-- >>> "good"
-- >>> :}
-- "good"

### Failure in Foo.hs:364: expression `:{
 let result = "good"
 "good"
:}'
expected: "good"
 but got:
          <interactive>:436:2: error:
              parse error (possibly incorrect indentation or mismatched brackets)

{-# LANGUAGE DataKinds #-}

type Str = "sugar"

main :: IO ()
main = return ()

$ stack
stack: error while loading shared libraries: libHSyaml-0.8.24-2wdOOQKc6Dt63OCZo8Nf1H-ghc8.2.1.so: cannot open shared object file: No such file or directory

$ yaourt -U /var/cache/pacman/pkg/stack-1.4.0-37-x86_64.pkg.tar.xz
$ yaourt -S haskell-stack-git
# PKGBUILDの編集で、依存関係からtlibinfoとstackを消す

$ cd {a-stack-project} && stack build
Configuring clock-0.7.2...
Building clock-0.7.2...
Preprocessing library clock-0.7.2...
/tmp/stack19865/clock-0.7.2/Clock.hsc:44:0: 警告: "hsc_alignment" が再定義されました
/tmp/stack19865/clock-0.7.2/In file included from .stack-work/dist/x86_64-linux-tinfo6-nopie/Cabal-1.24.2.0/build/System/Clock_hsc_make.c:1:0:
/home/aiya000/.stack/programs/x86_64-linux/ghc-tinfo6-nopie-8.0.2/lib/ghc-8.0.2/template-hsc.h:88:0: 備考: ここが以前の宣言がある位置です
#define hsc_alignment(t...) \

/bin/ld: .stack-work/dist/x86_64-linux-tinfo6-nopie/Cabal-1.24.2.0/build/System/Clock_hsc_make.o: relocation R_X86_64_32 against `.rodata' can not be used when making a shared object。 -fPIC を付けて再コンパイルしてください。
/bin/ld: 最終リンクに失敗しました: 出力に対応するセクションがありません
collect2: エラー: ld はステータス 1 で終了しました

import Numeric.Extra (intToDouble)

main :: IO ()
main = do
  n <- (readLn :: IO Int)
  xs <- sequence $ replicate n (readLn :: IO Int)
  if n == 3
     then case divTotal xs of
               Just result -> putStrLn $ "succeed: " ++ show result
               Nothing     -> putStrLn "The caluculation is failed"
     else putStrLn "x("

divTotal :: [Int] -> Maybe Int
divTotal [] = Nothing
divTotal xs =
  let (x':xs') = map intToDouble xs
  in truncate <$> foldr (flip (/?)) (Just x') xs'
  where
    -- Safe (/)
    (/?) :: Maybe Double -> Double -> Maybe Double
    Nothing /? _  = Nothing
    Just 0  /? _  = Nothing
    Just x  /? y  = Just $ x / y

-- Fooは作用
Eff Foo a

class Foo (a :: * -> *)

data Bar a = Bar Int a
type Baz a b = Either (Bar a) b

class Foo (Baz a)

myLayoutHook :: Choose (ModifiedLayout Gaps (Choose (ModifiedLayout (Decoration TabbedDecoration DefaultShrinker) (ModifiedLayout (Sublayout Simplest) TwoPane)) Grid)) Full Window
myLayoutHook = (taskbarMargin $ twoTabbedPane ||| Grid) ||| Full
  where
    taskbarMargin = gaps [(D, 40)]
    twoTabbedPane = subTabbed $ TwoPane (1/55) (1/2)

infixr 1 :$
type (:$) = ModifiedLayout

type (:.) x y z = x :$ (y :$ z)

infixr 2 :|||
type (:|||) = Choose

type MyLayoutHook  = (TaskbarMargin :$ TwoTabbedPane :||| Grid) :||| Full
type TaskbarMargin = Gaps
type TwoTabbedPane = SubTabbed TwoPane
type SubTabbed x   = (Decoration TabbedDecoration DefaultShrinker :. Sublayout Simplest) x

myLayoutHook :: MyLayoutHook Window
myLayoutHook = (taskbarMargin $ twoTabbedPane ||| Grid) ||| Full
  where
    taskbarMargin = gaps [(D, 40)]
    twoTabbedPane = subTabbed $ TwoPane (1/55) (1/2)

type MyLayoutHook = (TaskbarMargin :$ TwoTabbedPane :||| Grid) :||| Full
{--} myLayoutHook = (taskbarMargin  $ twoTabbedPane  ||| Grid)  ||| Full

main :: IO ()
main = print 10

$ cd /usr/lib
$ sudo cp libncurses.so{,.bak}
$ sudo ln -s libncursesw.so.6.0 libncurses.so

{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE OverloadedStrings #-}

import Data.String (IsString)
import Data.Text (Text)

newtype A = A Text deriving (IsString, Show)

a :: A
a = "ahoge"  -- 文字列リテラル of A

main :: IO ()
main = print a

$ git clone https://github.com/yi-editor/yi yi
$ cd yi/yi
$ LANG=C stack setup
$ LANG=C stack build
$ LANG=C stack install

Prelude> import Data.Char
Prelude Data.Char> isAlpha 'あ'
True
Prelude Data.Char> isAlphaNum 'あ'
True

clOptions :: CommandLineOptions
clOptions = CommandLineOptions
  { frontend    = "vty"   &= help "The frontend to use"
  , startOnLine = Nothing &= help "Open the (last) file on line NUM"
  , files       = []      &= help "FILES..." &= args  -- ここ
  }