erantapaa

{-# LANGUAGE BangPatterns #-}

import Data.Array.IO
import Data.Array.Unboxed
import Control.Monad

collatz x
  | even x    = div x 2
  | otherwise = 3*x+1

erantapaa

import System.Environment
import qualified Data.Array as A
import Data.Array.IO
import qualified Data.Array.MArray as M
import Data.Array.Base  ( UArray, unsafeFreezeSTUArray )
import Data.Array.Unboxed
import qualified Data.Array.Unboxed as U
import Control.Monad
import Debug.Trace
import Pipes

erantapaa

Check list for installing gtk 2.x for Haskell on OSX:

1. Install XQuartz (link) - this is needed for the xcb-shm package config file.
2. brew install gtk+
3. export PKG_CONFIG_PATH=/usr/local/Cellar/cairo/(...whatever...)/lib/pkgconfig:/opt/X11/lib/pkgconfig/:
4. Make sure alex and happy are installed - they are needed by gtk2hs-buildtools
5. cabal install gtk2hs-buildtools
6. cabal install gtk

erantapaa

import System.TimeIt
import System.Environment
import Text.Printf

subsequencesOfSize1 :: Int -> [a] -> [[a]]
subsequencesOfSize1 n xs = let l = length xs
                          in if n>l then [] else subsequencesBySize xs !! (l-n)
 where
   subsequencesBySize [] = [[[]]]
   subsequencesBySize (x:xs) = let next = subsequencesBySize xs

erantapaa

-- A receipe for using StateT with haskeline's InputT transformer.
-- Derived from this /r/haskell post: http://www.reddit.com/r/haskell/comments/1os0yq/haskeline_woes/
--
-- The key is using Control.Monad.State.Strict - using .Lazy doesn't work.

import Control.Monad.State.Strict
import Control.Monad.Trans (lift)
import System.Console.Haskeline