tonyday567

{-# LANGUAGE ExistentialQuantification #-}
{-# OPTIONS_GHC -fno-warn-missing-signatures -fno-warn-type-defaults -fno-warn-unused-do-bind -fno-warn-unused-imports -fno-warn-orphans #-}

module Main where

import Control.Applicative
import Data.List (foldl')
import Data.Monoid
import Data.Strict.Tuple
import Prelude hiding (sum, length)

tonyday567

module Main where

import Control.Concurrent hiding (yield)
import Control.Concurrent.Chan
import Data.Char (chr)
import Data.Maybe
import Control.Monad
import Control.Monad.Random ( RandomGen, Rand, getRandomR, evalRandIO)
import Control.Monad.Trans.State.Strict (StateT, get, put, evalStateT)
import Data.List

tonyday567

{-# LANGUAGE RankNTypes #-}
{-# OPTIONS_GHC -fno-warn-missing-signatures -fno-warn-type-defaults -fno-warn-unused-do-bind -fno-warn-unused-imports -fno-warn-orphans #-}

--
-- Random walk emitter with go and stop button
--

module Main where

import           Control.Applicative

tonyday567

{-# LANGUAGE Arrows #-}

import           Prelude hiding ((.), id)

import           Control.Arrow (Arrow(arr, first), ArrowChoice(left))
import           Control.Category (Category((.), id))
import           Control.Foldl
import           Control.Monad ((>=>))
import           Control.Monad.Trans.State.Strict (get, put)
import           Pipes

tonyday567

bird
----

> {-# LANGUAGE GADTs, TypeSynonymInstances #-}
> module ArcChallenge where
>
> import Control.Applicative
> import Control.Applicative.Error (Failing (..))
> import Control.Monad (ap)

tonyday567

In this gist we will first show that we can beat the arc challenge
(http://www.paulgraham.com/arcchallenge.html), and then build the library that
shows how we did it. This gist is Literate Haskell and is of course executable. The packages needed are happstack-server and applicative-extras, installable using cabal.

Let's start with some imports (for now, you can ignore these)

> {-# LANGUAGE GADTs, TypeSynonymInstances #-}
> module ArcChallenge where
>
> import Control.Applicative

tonyday567

literate haskell test

> {-# LANGUAGE RankNTypes, KindSignatures #-}

> module ArcChallenge where
>
> import Control.Applicative

> module ArcChallenge where
>

tonyday567

body {
  font-family: Helvetica, arial, sans-serif;
  font-size: 14px;
  line-height: 1.6;
  padding-top: 10px;
  padding-bottom: 10px;
  background-color: white;
  padding: 30px; }

body > *:first-child {

tonyday567

{-# LANGUAGE ExistentialQuantification, RankNTypes #-}

module Scanl where

import           Control.Foldl (Fold(..))
import           Data.Foldable (Foldable)
import qualified Data.Foldable as F
import           Data.Traversable

scan :: (Foldable f) => Fold a b -> f a -> [b]

tonyday567

{-# LANGUAGE DeriveGeneric #-}
{-# LANGUAGE DefaultSignatures #-}

import GHC.Generics
import Control.Applicative
import Data.Text.Encoding
import           Data.Aeson
import           Data.Aeson.Types
import qualified Data.ByteString as B
import qualified Data.ByteString.Lazy as LB