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
740
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
540
Ruby Trivia 3
sferik
0
670
Ruby Trivia 2
sferik
0
710
Ruby Trivia
sferik
2
1.3k
💀 Symbols
sferik
5
1.8k
Content Negotiation for REST APIs
sferik
8
960
Writing Fast Ruby
sferik
628
61k
Mutation Testing with Mutant
sferik
5
1.1k
Other Decks in Programming
See All in Programming
プログラミング教育のコスパの話
superkinoko
0
110
ニックトレイン登壇資料
ryotakurokawa
0
140
Django for Data Science (Boston Python Meetup, March 2025)
wsvincent
0
220
RailsでCQRS/ESをやってみたきづき
suzukimar
2
1.5k
JavaOne 2025: Advancing Java Profiling
jbachorik
1
310
Go1.24で testing.B.Loopが爆誕
kuro_kurorrr
0
150
Node.js, Deno, Bun 最新動向とその所感について
yosuke_furukawa
PRO
6
3k
パスキーのすべて / 20250324 iddance Lesson.5
kuralab
0
110
php-fpm がリクエスト処理する仕組みを追う / Tracing-How-php-fpm-Handles-Requests
shin1x1
5
810
Functional APIから再考するLangGraphを使う理由
os1ma
5
650
ステートソーシング型イベント駆動の視点で捉えるCQRS+ES
shinnosuke0522
1
310
アーキテクトと美学 / Architecture and Aesthetics
nrslib
12
2.9k
Featured
See All Featured
The World Runs on Bad Software
bkeepers
PRO
67
11k
The Illustrated Children's Guide to Kubernetes
chrisshort
48
49k
A Modern Web Designer's Workflow
chriscoyier
693
190k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
656
60k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
47
5.3k
How To Stay Up To Date on Web Technology
chriscoyier
790
250k
Principles of Awesome APIs and How to Build Them.
keavy
126
17k
Let's Do A Bunch of Simple Stuff to Make Websites Faster
chriscoyier
507
140k
What’s in a name? Adding method to the madness
productmarketing
PRO
22
3.4k
Adopting Sorbet at Scale
ufuk
75
9.3k
Side Projects
sachag
452
42k
Cheating the UX When There Is Nothing More to Optimize - PixelPioneers
stephaniewalter
280
13k
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