Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Snake Snacks: Function Composition, The Dumb Way
Search
Brian Hicks
September 07, 2017
Technology
0
130
Snake Snacks: Function Composition, The Dumb Way
Brian Hicks
September 07, 2017
Tweet
Share
More Decks by Brian Hicks
See All by Brian Hicks
Esperanto
brianhicks
0
130
Make Snacks: Yet Another JavaScript Build System
brianhicks
0
98
State of Elm 2017
brianhicks
1
530
µKanren: A Minimal Functional Core for Relational Programming
brianhicks
0
430
Terraform All The Things!
brianhicks
2
390
Kubernetes for the Mesos User
brianhicks
1
100
ch-ch-ch-ch-changes in Elm 0.17.0
brianhicks
2
1.8k
State of Elm 2016
brianhicks
3
540
Mesos + Consul = Developer Happiness (JUG)
brianhicks
1
130
Other Decks in Technology
See All in Technology
ガバメントクラウド(AWS)へのデータ移行戦略の立て方【虎の巻】 / 20251011 Mitsutosi Matsuo
shift_evolve
PRO
2
200
Findy Team+ QAチーム これからのチャレンジ!
findy_eventslides
0
190
LLMアプリの地上戦開発計画と運用実践 / 2025.10.15 GPU UNITE 2025
smiyawaki0820
1
560
RDS の負荷が高い場合に AWS で取りうる具体策 N 連発/a-series-of-specific-countermeasures-available-on-aws-when-rds-is-under-high-load
emiki
1
230
LLM時代にデータエンジニアの役割はどう変わるか?
ikkimiyazaki
6
1.4k
Git in Team
kawaguti
PRO
3
370
大規模サーバーレスAPIの堅牢性・信頼性設計 〜AWSのベストプラクティスから始まる現実的制約との向き合い方〜
maimyyym
9
4.7k
20251014_Pythonを実務で徹底的に使いこなした話
ippei0923
0
190
OAuthからOIDCへ ― 認可の仕組みが認証に拡張されるまで
yamatai1212
0
120
Sansan Engineering Unit 紹介資料
sansan33
PRO
1
3k
Bill One 開発エンジニア 紹介資料
sansan33
PRO
4
14k
リセラー企業のテクサポ担当が考える、生成 AI 時代のトラブルシュート 2025
kazzpapa3
1
330
Featured
See All Featured
Raft: Consensus for Rubyists
vanstee
140
7.1k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
189
55k
Code Review Best Practice
trishagee
72
19k
[RailsConf 2023 Opening Keynote] The Magic of Rails
eileencodes
31
9.7k
The Art of Programming - Codeland 2020
erikaheidi
56
14k
Mobile First: as difficult as doing things right
swwweet
224
10k
The Language of Interfaces
destraynor
162
25k
Thoughts on Productivity
jonyablonski
70
4.9k
Reflections from 52 weeks, 52 projects
jeffersonlam
353
21k
Fireside Chat
paigeccino
40
3.7k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
508
140k
Why Our Code Smells
bkeepers
PRO
340
57k
Transcript
Snake Snacks FUNCTION COMPOSITION, THE DUMB WAY
WHAT WE WANT def inc(n): return n + 1 def
double(n): return n * 2 # in the REPL >>> (inc >> double)(2) 6 >>> (double >> inc)(2) 5
HOW ARE WE GONNA GET THERE? The Worst Way Possible™
DOUBLE UNDERSCORE METHODS
DOUBLE UNDERSCORE METHODS
DUNDER METHODS
DUNDER MIFFLIN
DUNDER METHODS, THE NICE WAY class Boss(object): def __init__(self, name):
self.name = name def __str__(self): return self.name def __repr__(self): return '<%s: %s>' % (self.__class__.__name__, self) def introduce(self): return "Please meet my boss, %s" % self
DUNDER METHODS, THE NICE WAY >>> b = Boss("Michael Scott")
>>> b <Boss: Michael Scott> >>> str(b) 'Michael Scott' >>> b.introduce() 'Please meet my boss, Michael Scott'
! DECORATORS "
DECORATORS, THE NICE WAY def memoize(fn): cache = {} def
inner(*args, **kwargs): key = str((args, kwargs)) if key not in cache: cache[key] = fn(*args, **kwargs) return cache[key] return inner
DECORATORS, THE NICE WAY @memoize def hype(stuff): return "OH YEAH,
IT'S %s" % stuff.upper() # is the same as... hype = memoize(lambda stuff: "OH YEAH, IT'S %s" % stuff.upper())
DECORATORS, THE NICE WAY >>> hype("cheese") "OH YEAH, IT'S CHEESE"
>>> hype("a moose") "OH YEAH, IT'S A MOOSE"
BUT… OBJECTS! class memoize(object): def __init__(self, fn): self.cache = {}
self.fn = fn def __call__(self, *args, **kwargs): key = str((args, kwargs)) if key not in self.cache: self.cache[key] = self.fn(*args, **kwargs) return self.cache[key]
BUT… OBJECTS! >>> hype("cheese") "OH YEAH, IT'S CHEESE" >>> hype("a
moose") "OH YEAH, IT'S A MOOSE" >>> hype.cache {"(('a moose',), {})": "OH YEAH, IT'S A MOOSE", "(('cheese',), {})": "OH YEAH, IT'S CHEESE"}
__gt__ class ChessPlayer(object): def __init__(self, name, elo): self.name = name
self.elo = elo def __gt__(self, other): return self.elo > other.elo
__gt__ >>> carlsen = ChessPlayer("Carlsen, Magnus", 2827) >>> almasi =
ChessPlayer("Almasi, Zoltan", 2707) >>> carlsen > almasi True >>> carlsen < almasi False
OUR FIRST TRY! class composable(object): def __init__(self, fn): self.fn =
fn def __call__(self, *args, **kwargs): return self.fn(*args, **kwargs) def __gt__(self, other): return self.__class__( lambda *args, **kwargs: other(self.fn(*args, **kwargs)) )
OUR FIRST TRY! @composable def inc(n): return n + 1
@composable def double(n): return n * 2 @composable def triple(n): return n * 3
OUR FIRST TRY! >>> (inc > inc)(0) 2 >>> (inc
> inc > inc)(0) 2
OUR FIRST TRY! ! 1 > 2 > 3 #
is equivalent to 1 > 2 and 2 > 3 # NOT (1 > 2) > 3
__rshift__ TO THE RESCUE! class composable(object): def __init__(self, fn): self.fn
= fn def __call__(self, *args, **kwargs): return self.fn(*args, **kwargs) def __rshift__(self, other): return self.__class__( lambda *args, **kwargs: other(self.fn(*args, **kwargs)) )
__rshift__ TO THE RESCUE! >>> (inc >> inc)(0) 2 >>>
(inc >> inc >> inc)(0) 3
__rshift__ TO THE RESCUE! >>> (inc >> double)(2) 6 >>>
(double >> inc)(2) 5 >>> (inc >> double >> triple)(2) 18
THANK YOU I'M SORRY