Python to Haskell

Python is a terrific everyday tool for solving practical tasks, but there always was a missing thing here and there. Vlad has tried many languages during his career as an engineer, got excited with a functional programming community and settled with using Haskell as a prime-time instrument. Come to the talk to find out what's going on. In this talk passion is going to be (almost) purely technical and no hello worlds, promise.

Presented at PyCon Ukraine 2014

Transcript

1. from%the%first% love%to%a% serious% rela0onship pycon ukraine 2014 @darkproger
2. based&on&a&true& story
3. Python'is'awesome
5. zero%to%webapp%in%minutes
7. complex(webapps(for( embedded(systems
9. boring'forms
11. interac(ve*hacking
12. other&uses • data$robots,$apparently • scien'fic)compu'ng,)machine)learning,)etc • desktop)GUIs • build)tools,)system)hacking • ad<hoc)automa'on,)scripts
13. so#why#even#bother#looking#elsewhere?
14. movember
15. Democra(za(on thank&you&Erik&Meijer&(see&"Wisdom&of&the&cloud"&on&TEDx&Del<,&2011)
16. Educa&on
18. food hun$ng&➡&growing ➡!supermarkets
19. abstrac'on ignoring&irrelevant&details old$skills$become$impediment$in$the$new$world
21. special(human(throwing(coal( into(a(big(burning(hole
23. wheel pedals gear%s'ck
25. cloud&compu)ng distributed)systems
26. programming a = 1 # ... b = {'key': 1} # ... c = open('/System/Library/Kernels/kernel').read() # ... d = requests.get(url)
27. 1950's'era'tools • state • destruc*ve,assignment • side1effects • sequen*al,composi*on
29. 1950's'era'tools a = 1 # ... b = {'key': 1} # ... c = open('/System/Library/Kernels/kernel').read() # ... d = requests.get(url)
31. stuff%taking%+me!%can%no% longer%be%implicit !"Systems"Performance:"Enterprise"and"the"Cloud
32. adop%ng(a(language(to(the(new( world @asyncio.coroutine def test(): yield from asyncio.async(create()) yield from asyncio.async(write()) yield from asyncio.async(close()) yield from asyncio.sleep(2.0) loop.stop()
33. python'3
36. erlang
37. paradigm(shi+1 process'per'physical'en.ty language'+'OS 1"deserves"another"talk"really
38. (>>=)
41. (>>=) • pure&func*ons:&(+) :: Int -> Int -> Int • combinators:&fix f = f (fix f) • HOFs:&unwords . map (++ ",") . words • pa6ern&matching:&case x of Just y -> y • ADTs: data Tree a = Branch a (Tree a) (Tree a) | Leaf deriving (Functor) • persistent)data)structures
42. Lazy%evalua*on STG$machine
43. category) theory
44. • functors*<$> • semigroups*+ • applica2ves*<*> • monoids*0 + • monads*>>=
45. I"don't"use"mathema.cs"for"the"sake"of"using" mathema.cs."The"purpose"behind"structuring" programs"mathema.cally"is"to"compose"small"bits"of" mathema.cal"func.onality,"each"of"which"is"correct"in" isola.on,"to"build"larger"mathema.cal"structures" which"are"s.ll"correct. !!"haskellforall.com
46. type%checker!
53. shell
54. haskell
57. newtype Process = Process ByteString newtype Host = Host ByteString newtype Addr = Addr (IP, ByteString) data OpenFile = Connection Host Process Addr Addr | Listen Host Process Addr data IP = IP ByteString | Any type IPMap = Map IP Host
58. h"ps:/ /github.com/zalora/upcast
59. DSL$driven+development • Free%applica+ves • Free%monads • quasi%quo+ng%(php%+%sql%+%html%+%css%on%one%page% anyone?) • template%haskell • generics
60. haxl h"ps:/ /github.com/facebook/Haxl
61. numCommonFriends x y = length <$> (intersect <$> friendsOf x <*> friendsOf y) λ :t (<*>) (<*>) :: Applicative f => f (a -> b) -> f a -> f b
62. tes$ng • types • quickcheck • can/s0ll/do/tdd/if/you/like/wri0ng/tests • just/ship/it/:)
63. doing&ops • sta%c'binaries! • RTS'is'C • imporved'IO'manager'in'7.8 • lazy'evalua%on'impedes'Intel'reality • (say'something'bad'about'callbacks'here) • extended'DWARF'support'coming'in'7.10 • more'stuff'about'GHC/RTS'stacks
64. community!is!awesome you$can$find$many$(ex.)python$folks$there
65. Python: "Easy&things&are&easy,&hard& things&are&possible" Haskell: "Hard&things&are&easy,&the& impossible&just&happened"
66. kthxbai <3