Objects, Objects Everywhere

Objects, Objects Everywhere Mike Pack @zombidev

Let’s Talk Objects Behavior + State

Let’s Talk Objects BehaviorI’m a person, what can I do? Walk Talk Eat Could also be deﬁned as: Move Legs Move Lips Ingest Food

Let’s Talk Objects BehaviorLevel of abstraction matters! Behavioral abstraction varies per domain.

Let’s Talk Objects StateI’m a person, who am I currently? Mike Pack Male Brown Therefore, I have attributes: Name Gender Hair Color

Let’s Talk Objects State States changeWhen I’m 70, my attributes might be: Mike Pack Male Grey

Let’s Talk Objects Behavior changes too!I just learned to jump, now my behavior is: Walk Talk Eat Jump

Let’s Talk Objects Behavior + State

HTML<div id=”name”> Mike</div> Is this an object?

Attribute HTML Name<div id=”name”> Mike</div> Is this an object?

Attribute HTML Name<div id=”name”> Mike State</div> Is this an object?

Attribute HTML Name<div id=”name”> Mike the beef?Where’s State</div> Is this an object?

Attribute HTML Name <div id=”name”> Mike behavior?Where’s the State </div> Is this an object?

HTML<div id=”name” onclick=”...”> Mike</div> Is this an object?

Attribute HTML Name<div id=”name” onclick=”...”> Mike Behavior!</div> State Is this an object?

HTML HTML is object oriented (albeit, not for purist)HTML does not exhibit other properties of an OO systems:- Inheritance- Polymorphism- etc

HTML Don’t use onclick=”...”However, without onclick, HTML does not exhibit behavior.

CSSa{ color: red;} Is this an object?

CSS Attributea{ Name color: red;} Is this an object?

CSS Attributea{ Name color: red;} State Is this an object?

CSS Attribute a{ Name color:the beef?Where’s red; } State Is this an object?

CSSa{ color: red; &:hover { color: blue; }}Is this an object?

Attribute CSS Name a { color: red; Behavior! &:hover { color: blue; } State } Is this an object?

CSS a{Behavior color: red; State &:hover { Change color: blue; } } Behavior changes state.

CSS CSS is object oriented (not for purist)CSS does not exhibit other properties of an OO systems:- Inheritance- Polymorphism- etc

JavaScriptvar book = { title: “The Art of War”}; Is this an object?

Attribute Name JavaScript var book = { title: “The Art of War” }; Is this an object?

Attribute Name JavaScript var book = { title: “The Art of War” State }; Is this an object?

Attribute Name JavaScript var book = { title: “The Art of Where’s the beef? War” State }; Is this an object?

Attribute Name JavaScript var book = { title: “The Art of Where’s the beef? It’sWar” implicit! State }; Is this an object?

JavaScriptvar book = { title: “The Art of War”, constructor: function() {...}, hasOwnProperty: function() {...}, ...}; Implicit behavior.

JavaScriptJavaScript is object oriented (of course)

JavaScriptIt’s not entirely object oriented JavaScript has primitives, too.

JavaScriptIf it’s an object, typeof knows typeof {} === ‘object’ //=> true

JavaScriptIntegers are not objectstypeof 1 === ‘object’ //=> false

JavaScript undeﬁned is not an objecttypeof undeﬁned === ‘object’ //=> false

JavaScriptLiterals are not always primitives typeof [] === ‘object’ //=> true

JavaScript typeof might not return object typeof true === ‘object’ //=> false typeof true === ‘boolean’ //=> true But booleans are objects!new Boolean(1).valueOf() === true //=> true

JavaScriptCareful, typeof can bitetypeof null === ‘object’ //=> true new Null() //=> error

Ruby 1Is this an object?

Ruby State (accessor) 11.real #=> 1Is this an object?

Ruby State (accessor) 11.real #=> 11 + 1 #=> 2Is this an object?

Ruby State 1 (accessor) 1.real #=> 1Behavior 1 + 1 #=> 2 1.+(1) #=> 2 Is this an object?

RubyRuby is object oriented

RubyEverything is an object

RubyLiteral arrays are new objects [].object_id #=> 70318249770140 [].object_id #=> 70318249594160

RubyLiteral strings are new objects‘slurpy’.object_id #=> 70318249561400‘slurpy’.object_id #=> 70318249500340

RubyLiteral hashes are new objects {}.object_id #=> 7019206373870 {}.object_id #=> 70192063701240

RubyLiteral regexs are new objects //.object_id #=> 70192063385520 //.object_id #=> 70192067965040

RubyLiteral ranges are new objects (1..2).object_id #=> 70192067946460 (1..2).object_id #=> 70192067921120

Ruby Not everything creates a new objectRuby has singleton objects (objects instantiated once).

Rubynil is a singleton nil.object_id #=> 4 nil.object_id #=> 4

Rubybooleans are singletons false.object_id #=> 0 false.object_id #=> 0 true.object_id #=> 2 true.object_id #=> 2

RubyNumbers are singletons 1.object_id #=> 3 1.object_id #=> 3

Ruby um s xnFi Numbers are singletons 1.object_id #=> 3 1.object_id #=> 3

RubyBignums are not singletons4611686018427387904.object_id #=> 701920637307404611686018427387904.object_id #=> 70192063508580

Ruby Bignums are not singletons 4611686018427387904.object_id #=> 70192063730740 4611686018427387904.object_id #=> 70192063508580Why 4611686018427387904?

bytes to store Ruby integerbytes = 0.size #=> 8

bytes to store Ruby integerbytes = 0.size #=> 8 8 bits per bytebits = bytes * 8 #=> 64 64 bit machine

bytes to store Ruby integerbytes = 0.size #=> 8 8 bits per bytebits = bytes * 8 #=> 64 64 bit machine 1 bit for sign + 1 bit for Ruby2 ** (bits - 2) #=>4611686018427387904

Ruby 4611686018427387904 Bignum Diﬀerent objects.4611686018427387904 - 1 Fixnum Singleton object.

RubyWhy does nil have object_id of 4? 1 have object_id of 3? true have object_id of 2?

RubyBecause Matz says so false.object_id #=> 0 0.object_id #=> 1 true.object_id #=> 2 1.object_id #=> 3 nil.object_id #=> 4 2.object_id #=> 5

Ruby Find by object_idObjectSpace._id2ref(0) #=> falseObjectSpace._id2ref(1) #=> 0ObjectSpace._id2ref(2) #=> trueObjectSpace._id2ref(3) #=> 1ObjectSpace._id2ref(4) #=> nilObjectSpace._id2ref(5) #=> 2ObjectSpace._id2ref(6) #=> errorObjectSpace._id2ref(7) #=> 3ObjectSpace._id2ref(8) #=> error

RubyNegative object_ids -1.object_id #=> -1 -2.object_id #=> -3 -3.object_id #=> -5

Objects.useful? # => true

Objects.useful? # => trueConsistent modeling across the stack.

Objects.useful? # => trueHelpful in representing the real world.

Objects.useful? # => true Fun and expressive.

Thanks!@zombidev

Objects, Objects Everywhere

by mikepack on Nov 15, 2012

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