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
The Value of Being Lazy
Search
Erik Berlin
November 24, 2015
Programming
3
770
The Value of Being Lazy
…or How I Made OpenStruct 10X Faster
Presented at Rails Israel 2015.
Erik Berlin
November 24, 2015
Tweet
Share
More Decks by Erik Berlin
See All by Erik Berlin
Enumerator::Lazy
sferik
2
570
Ruby Trivia 3
sferik
0
700
Ruby Trivia 2
sferik
0
750
Ruby Trivia
sferik
2
1.3k
💀 Symbols
sferik
5
1.9k
Content Negotiation for REST APIs
sferik
8
990
Writing Fast Ruby
sferik
628
62k
Mutation Testing with Mutant
sferik
5
1.1k
Other Decks in Programming
See All in Programming
Webの外へ飛び出せ NativePHPが切り拓くPHPの未来
takuyakatsusa
2
550
AIと”コードの評価関数”を共有する / Share the "code evaluation function" with AI
euglena1215
1
170
XP, Testing and ninja testing
m_seki
3
250
RailsGirls IZUMO スポンサーLT
16bitidol
0
190
Python型ヒント完全ガイド 初心者でも分かる、現代的で実践的な使い方
mickey_kubo
1
120
iOS 26にアップデートすると実機でのHot Reloadができない?
umigishiaoi
0
130
Blazing Fast UI Development with Compose Hot Reload (droidcon New York 2025)
zsmb
1
290
設計やレビューに悩んでいるPHPerに贈る、クリーンなオブジェクト設計の指針たち
panda_program
6
2.1k
Hack Claude Code with Claude Code
choplin
4
2.1k
おやつのお供はお決まりですか?@WWDC25 Recap -Japan-\(region).swift
shingangan
0
140
5つのアンチパターンから学ぶLT設計
narihara
1
170
技術同人誌をMCP Serverにしてみた
74th
1
650
Featured
See All Featured
Building a Scalable Design System with Sketch
lauravandoore
462
33k
Agile that works and the tools we love
rasmusluckow
329
21k
Templates, Plugins, & Blocks: Oh My! Creating the theme that thinks of everything
marktimemedia
31
2.4k
Measuring & Analyzing Core Web Vitals
bluesmoon
7
510
It's Worth the Effort
3n
185
28k
What's in a price? How to price your products and services
michaelherold
246
12k
Become a Pro
speakerdeck
PRO
29
5.4k
VelocityConf: Rendering Performance Case Studies
addyosmani
332
24k
Docker and Python
trallard
44
3.5k
Principles of Awesome APIs and How to Build Them.
keavy
126
17k
Visualization
eitanlees
146
16k
The Invisible Side of Design
smashingmag
301
51k
Transcript
THE VALUE OF BEING LAZY or How I Made OpenStruct
10X Faster Erik Michaels-Ober @sferik
In Ruby, everything is an object. ∀ thing thing.is_a?(Object) #=>
true
In Ruby, every object has a class. ∀ object object.respond_to?(:class)
#=> true
In Ruby, every class has a class. ∴ Object.respond_to?(:class) #=>
true Object.class #=> Class
You can use classes to create new objects: object =
Object.new object.class #=> Object
You can use classes to create new classes: klass =
Class.new klass.class #=> Class
Usually, we create classes like this: class Point attr_accessor :x,
:y def initialize(x, y) @x, @y = x, y end end
You can replace such simple classes with structs: Point =
Struct.new(:x, :y)
OpenStruct requires even less definition: point = OpenStruct.new point.x =
1 point.y = 2
In this way, OpenStruct is similar to Hash: point =
Hash.new point[:x] = 1 point[:y] = 2
You can even initialize OpenStruct with a Hash: point =
OpenStruct.new(x: 1, y: 2) point.x #=> 1 point.y #=> 2
So why use OpenStruct instead of Hash?
Test double validator = OpenStruct.new expect(validator).to receive(:validate) code = PostalCode.new("94102",
validator) code.valid?
API response user = OpenStruct.new(JSON.parse(response)) user.name #=> Erik
Configuration object def options opts = OpenStruct.new yield opts opts
end
So OpenStruct is useful…but slow.
None
Steps to optimize code 1. Complain that code is slow
on Twitter 2. ??? 3. Profit
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
require "benchmark/ips" Point = Struct.new(:x, :y) def struct Point.new(0, 1)
end def ostruct OpenStruct.new(x: 0, y: 1) end Benchmark.ips do |x| x.report("ostruct") { ostruct } x.report("struct") { struct } end
Comparison: struct: 2927800.2 i/s ostruct: 84741.1 i/s - 34.55x slower
Actual steps to optimize code 1. Benchmark 2. Read code
3. Profit
def initialize(hash = nil) @table = {} if hash hash.each_pair
do |k, v| k = k.to_sym @table[k] = v new_ostruct_member(k) end end end
def new_ostruct_member(name) name = name.to_sym unless respond_to?(name) define_singleton_method(name) { @table[name]
} define_singleton_method("#{name}=") { |x| @table[name] = x } end name end
def method_missing(mid, *args) len = args.length if mname = mid[/.*(?==\z)/m]
@table[new_ostruct_member(mname)] = args[0] elsif len == 0 if @table.key?(mid) new_ostruct_member(mid) @table[mid] end end end
def initialize(hash = nil) @table = {} if hash hash.each_pair
do |k, v| k = k.to_sym @table[k] = v new_ostruct_member(k) end end end
Before: struct: 2927800.2 i/s ostruct: 84741.1 i/s - 34.55x slower
After: struct: 2927800.2 i/s ostruct: 940170.4 i/s - 3.11x slower
None
None
git log --reverse lib/ostruct.rb
None
Lazy evaluation
Enumerator::Lazy
lazy_integers = (1..Float::INFINITY).lazy lazy_integers.collect { |x| x ** 2 }.
select { |x| x.even? }. reject { |x| x < 1000 }. first(5) #=> [1024, 1156, 1296, 1444, 1600]
require "prime" lazy_primes = Prime.lazy lazy_primes.select { |x| (x -
2).prime? }. collect { |x| [x - 2, x] }. first(5) #=> [[3, 5], [5, 7], [11, 13], [17, 19], [29, 31]]
module Enumerable def repeat_after_first unless block_given? return to_enum(__method__) { size
* 2 - 1 if size } end each.with_index do |*val, index| index == 0 ? yield *val : 2.times { yield *val } end end end
require "prime" lazy_primes = Prime.lazy lazy_primes.repeat_after_first. each_slice(2). select { |x,
y| x + 2 == y }. first(5) #=> [[3, 5], [5, 7], [11, 13], [17, 19], [29, 31]]
require "date" lazy_dates = (Date.today..Date.new(9999)).lazy lazy_dates.select { |d| d.day ==
13 }. select { |d| d.friday? }. first(10)
lazy_file = File.readlines("/path/to/file").lazy lazy_file.detect { |x| x =~ /regexp/ }
Being lazy is efficient.
Being lazy is elegant.
Thanks to: Zachary Scott ROSS Conf Rails Israel
Thank you