Zsolt Dollenstein zsol

Why Haskell Matters to You

Why are we at Prezi pushing Haskell adoption internally? Why bother having the fourth production application written in a lazy, statically typed, purely functional language? What are the good parts and more interestingly, what have been the painful points so far? Be prepared for some production code examples.

Prezi.com

Prezi is a virtual whiteboard that transforms presentations from monologues into conversations: enabling people to see, understand, and remember ideas. I'm Zsolt, a tech lead at Prezi: https://prezi.com/about/zsolt-dollenstein/

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I hereby claim:

I am zsol on github.
I am zsol (https://keybase.io/zsol) on keybase.
I have a public key whose fingerprint is 21EE A6A4 EF06 1CB2 0082 F208 0EA6 EB87 C124 0D6F

To claim this, I am signing this object:

	require 'formula'

	class GtkMacIntegration < Formula
	homepage 'https://live.gnome.org/GTK+/OSX'
	url 'ftp://ftp.gnome.org/pub/gnome/sources/gtk-mac-integration/2.0/gtk-mac-integration-2.0.1.tar.xz'
	version '2.0.1'
	sha1 '9d939a2e4fb6c0ab4fe3d544ac712a152451249a'
	head 'git://git.gnome.org/gtk-mac-integration'

	depends_on 'pkg-config' => :build

	{-# LANGUAGE GeneralizedNewtypeDeriving, GADTs, StandaloneDeriving #-}
	import Control.Monad.Identity
	import Control.Monad.Reader
	import Control.Monad.Writer
	import Control.Monad.Error
	import Control.Applicative
	import Data.Map
	import Prelude hiding (lookup, log)

	type Name = String

	#!/usr/bin/env runghc
	import System.Environment
	import Control.Monad.Writer
	import Control.Applicative

	mySum :: (Num a, Show a) => [a] -> Writer [String] a
	mySum [] = return 0
	mySum (x:xs) = censor ((show x):) ((x+) <$> mySum xs)

	main = do

	{-
	you need the memoize cabal package to use this.
	http://hackage.haskell.org/package/memoize-0.3
	-}

	import System.IO.Unsafe
	import System.Posix.Files
	import System.Posix.Types
	import Data.Function.Memoize
	import Debug.Trace

	{-# LANGUAGE OverloadedStrings #-}
	import qualified Data.Text as T
	import qualified Data.Text.IO as T
	import Data.Time
	import System.Exit
	import System.IO.Error
	import System.Locale

	format :: String
	format = "%Y-%m-%d %H:%M:%S,%q"

	{-# LANGUAGE TemplateHaskell #-}

	module Abesto(mkRead) where

	import Language.Haskell.TH
	import Data.Maybe

	constructors :: Info -> Maybe [Name]
	constructors (TyConI (DataD _cxt _name _bnds cons _names)) = Just $ catMaybes $ map getName cons
	where getName (NormalC name _types) = Just name

	module Card where

	import Data.Char

	produceDigits :: Integer -> [Int]
	produceDigits n = [(ord i) - 48\| i <- (show n)]

	doubleEveryOther :: [Int] -> [Int]
	doubleEveryOther l = case (length l) `mod` 2 of
	0 -> helper0 l

	#!/bin/bash

	set -e

	tmp=$(mktemp -d)

	trap "rm -rf $tmp" EXIT

	cd $tmp
	curl -O http://www.haskell.org/platform/download/2013.2.0.0/Haskell%20Platform%202013.2.0.0%2064bit.pkg