OOP in Elixir - Speaker Deck

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OOP in Elixir Wojtek Mach

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defmodule Person do defstruct [:name] end joe = %Person{name: "Joe"} robert = %Person{name: "Robert"} joe.name # => "Joe" robert.name # => "Robert"

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defmodule Person do defstruct [:name] def say_hello_to(from, to) do IO.puts("#{from.name}: Hello, #{to.name}") end end joe = %Person{name: "Joe"} robert = %Person{name: "Robert"} joe.name # => "Joe" robert.name # => "Robert" Person.say_hello_to(joe, robert) # => Joe: Hello, Robert

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import OOP

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import OOP class Person do var :name end

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import OOP class Person do var :name end joe = Person.new(name: "Joe") robert = Person.new(name: "Robert")

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import OOP class Person do var :name end joe = Person.new(name: "Joe") robert = Person.new(name: "Robert") joe.name() # => "Joe" robert.name # => "Robert"

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import OOP class Person do var :name def say_hello_to(who) do IO.puts("#{this.name}: #{who.name}") end end joe = Person.new(name: "Joe") robert = Person.new(name: "Robert") joe.name() # => "Joe" robert.name # => "Robert" joe.say_hello_to(robert) # => Joe: Hello, Robert

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import class var def end end joe robert joe.name() # => "Joe" robert.name # => "Robert" joe.say_hello_to(robert) # => Joe: Hello, Robert this.name

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joe = Person.new(name: "Joe") joe.set_name("Hipster Joe") # => :ok joe.name # => "Hipster Joe"

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Q: How does it work? 

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Q: How does it work?  A: You don’t want to know.

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Q: How does it work?  A: Macros.

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Perhaps it’s not that bad… 

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Q: What’s worse than OOP? 

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Q: What’s worse than OOP?  A: OOP with inheritance.

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import OOP class Human do var :name end

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import OOP class Human do var :name end class Doctor < Human do end

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import OOP class Human do var :name end class Doctor < Human do def title do "Dr. #{name}" end end

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import OOP class Human do var :name end class Doctor < Human do def title do "Dr. #{name}" end end dr = Doctor.new(name: "Jekyll") dr.title # => "Dr. Jekyll"

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Perhaps it’s not that bad… 

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Q: What’s worse than OOP with inheritance? 

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Q: What’s worse than OOP with inheritance?  A: OOP with multiple inheritance.

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import OOP class Human do end

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import OOP class Human do end class Spider do end

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import OOP class Human do end class Spider do end class Spiderman < [Human, Spider] do end

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Elixir Guidelines

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Q: What’s the 1st rule of writing macros?  Elixir Guidelines

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Q: What’s the 1st rule of writing macros?  A: Don’t write macros. Elixir Guidelines

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Q: What’s the 1st rule of doing OOP in Elixir?  Elixir Guidelines

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Q: What’s the 1st rule of doing OOP in Elixir?  A: Don’t do OOP in Elixir. Elixir Guidelines

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• Elixir is powerful           

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• Elixir is powerful • DSLs, abstractions, semantics       

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• Elixir is powerful • DSLs, abstractions, semantics • Complexity   

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• Elixir is powerful • DSLs, abstractions, semantics • Complexity • Simplicty

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Thank you! @wojtekmach wojtekmach/oop