Por que Ruby? - Speaker Deck

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Por que Ruby?

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Por que Ruby? @samﬂores

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No content

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Genéticas

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Genéticas Ambientais

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Genéticas Ambientais Comportamentais

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Objetividade

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class DoNothing { public static void main(String[] args) { // não faz nada! } }

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class DoNothing { public static void main(String[] args) { // não faz nada! } } # não faz nada!

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class Person { private String name; private Date birthday; public String getName() { return name; } public void setName(String value) { name = value; } public String getBirthday() { return birthday; } public void setBirtday(String value) { birthday = value; } }

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Expressividade

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public void deliver() { if (message.length != 0) { connection.send(message) } }

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public void deliver() { if (message.length != 0) { connection.send(message) } } def deliver connection.send(message) unless message.empty? end

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// int[] list = [1, 2, 3, ..., 100]; for (int i = 0; i < list.length; i++) { printf("%d", list[i]); }

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// int[] list = [1, 2, 3, ..., 100]; for (int i = 0; i < list.length; i++) { printf("%d", list[i]); } # list = (1..100).to_a list.each { |i| puts i }

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state_machine :status, initial: :draft do event :deliver do transition draft: :sent end before_transition on: :deliver do throw :halt if receivers.empty? notify end end

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Literais

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Map map = new HashMap(); map.put("um", 1); map.put("dois", 2); map.put("três", 3);

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Map map = new HashMap(); map.put("um", 1); map.put("dois", 2); map.put("três", 3); map = { "um" => 1, "dois" => 2, "três" => 3 }

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String cpf = "123.456.789-00"; Pattern pattern = Pattern.compile("^\\d{3}\\.\\d{3}\\.\\d{3}-\\d{2}$"); Matcher matcher = pattern.matcher( cpf ); if (matcher.matches()) { System.out.println( "Formato de CPF válido" ); } cpf = "123.456.789-00" if cpf =~ /^\d{3}\.\d{3}\.\d{3}-\d{2}$/ puts "Formato de CPF válido" end

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Orientação a Objetos

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"stressed".reverse # => desserts 1.odd? # => true receiver.non_existing_method # => pode ser que funcione ;) nil.nil? # => true

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Programação Funcional

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File.open("filename.txt") do |file| file.write("Some text") end (1..200).select do |number| number.prime? end code = -> { print "Hello world" } code.call

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File.open("filename.txt") do |file| file.write("Some text") end (1..200).select do |number| number.prime? end code = -> { print "Hello world" } code.call do |file| file.write("Some text") end do |number| number.prime? end -> { print "Hello world" }

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File.open("filename.txt") do |file| file.write("Some text") end (1..200).select do |number| number.prime? end code = -> { print "Hello world" } code.call number.prime?

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Monkey Patch

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class Fixnum def prime? return false if self < 2 return true if self == 2 factor = (2..(self / 2)).detect { |n| self % n == 0 } factor.nil? end end 31.prime? # => true

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Metaprogramação

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class Person < ActiveRecord::Base # no code here end person = Person.find_by_name_and_surname("Samuel", "Flores") person.name # => John person.birtday # => 1984-04-29

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deﬁne_method method_missing* instance_eval class_eval

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Packaging

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> gem install nokogiri

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> bundle install

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junit junit 4.10 test com.h2database h2 ${h2database.version} test org.springframework spring-test ${org.springframework-version} test

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junit junit 4.10 test com.h2database h2 ${h2database.version} test org.springframework spring-test ${org.springframework-version} test source "https://rubygems.org" gem 'sinatra', '1.4.1' gem 'dm-core', '1.2.0' gem 'dm-types', '1.2.2' gem 'dm-sqlite-adapter', '1.2.0' gem 'jdbc-sqlite3', '3.7.2', platforms: :jruby gem 'dm-zim-adapter', '0.0.1', platforms: :jruby gem 'do_zim', '0.0.1', platforms: :jruby gem 'dm-aggregates', '1.2.0' gem 'dm-validations', '1.2.0' gem 'dm-timestamps', '1.2.0' gem 'dm-serializer', '1.2.2' gem 'dm-migrations', '1.2.0'

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Automação

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> rake db:migrate

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@{elseText}

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@{elseText} desc 'Seed the DB' task :seed do Rake::Task['db:reset'].invoke seeds = TOML.load_file("db/seed.toml") time = Time.now seeds['user'].each do |key, attributes| User.create!(attributes.merge(created_at: time)) end end

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Testes

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class CalculatorTest < ActiveSupport::TestCase test "sum operation with more than 2 operands" do calc = Calculator.new assert calc.sum(1, 2, 3) == 6 end end

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describe CalculatorTest do let(:calc) { Calculator.new } it "sums more than 2 operands" do calc.sum(1, 2, 3).should == 6 end end

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Scenario: add more than two numbers Given I have entered 1 into the calculator And I have pressed the plus button And I have entered 2 into the calculator And I have pressed the plus button And I have entered 3 into the calculator When I press the equal button Then the result should be 6 on the screen

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Web

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> rails generate scaffold person name:string birthday:date active_record db/migrate/20130427142248_create_people.rb app/models/person.rb resource_route resources :people scaffold_controller app/controllers/people_controller.rb erb app/views/people app/views/people/index.html.erb app/views/people/edit.html.erb app/views/people/show.html.erb app/views/people/new.html.erb app/views/people/_form.html.erb . . .

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post '/', provides: 'application/json' do order = Order.new(params[:order]) raise InvalidRecordError.new(order.errors) unless order.save order.to_json end

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WEBrick Mongrel Thin Unicorn Rainbows Puma Passenger ...

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Desktop

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Shoes.app :height => 150, :width => 250 do background rgb(240, 250, 208) stack :margin => 10 do button "Start" do @time = Time.now @label.replace "Stop watch started at #@time" end button "Stop" do @label.replace "Stopped, ", strong("#{Time.now - @time}"), " seconds elapsed." end @label = para "Press ", strong("start"), " to begin timing." end end