DSL or NoDSL - Euruko - may 29, 2010

José Valim (@josevalim) from Plataforma talks about DSL or NoDSL at Euruko 2010 in Kraków/Poland.

Transcript

1. José Valim @josevalim blog.plataformatec.com DSL or NoDSL?
2. José Valim @josevalim blog.plataformatec.com blog twitter ID DSL or NoDSL?
3. José Valim @josevalim blog.plataformatec.com A brief introduction...
4. José Valim @josevalim blog.plataformatec.com A short story...
5. José Valim @josevalim blog.plataformatec.com
6. José Valim @josevalim blog.plataformatec.com mail_form
7. José Valim @josevalim blog.plataformatec.com Contact form recipe
8. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC)
9. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC) ✦ Model (30 LOC)
10. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC) ✦ Model (30 LOC) ✦ View (30 LOC)
11. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC) ✦ Model (30 LOC) ✦ View (30 LOC) ✦ Mailer (15 LOC)
12. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC) ✦ Model (30 LOC) ✦ View (30 LOC) ✦ Mailer (15 LOC) ✦ View (20 LOC)
13. José Valim @josevalim blog.plataformatec.com Contact form recipe ✦ Controller (20 LOC) ✦ Model (30 LOC) ✦ View (30 LOC) ✦ Mailer (15 LOC) ✦ View (20 LOC)
14. José Valim @josevalim blog.plataformatec.com Let’s create a DSL!
15. José Valim @josevalim blog.plataformatec.com Domain Specific Language
16. José Valim @josevalim blog.plataformatec.com class ContactForm < MailForm::Base to "jose.valim@plataformatec.com.br" from "contact_form@app_name.com" subject "Contact form" attributes :name, :email, :message end ContactForm.new(params[:contact_form]).deliver
17. José Valim @josevalim blog.plataformatec.com from { |c| "#{c.name} <#{c.email}>" }
18. José Valim @josevalim blog.plataformatec.com to :author_email def author_email Author.find(self.author_id).email end
19. José Valim @josevalim blog.plataformatec.com headers { |c| { "X-Spam" => "True" } if c.honey_pot }
20. José Valim @josevalim blog.plataformatec.com class ContactForm < MailForm::Base to :author_email from { |c| "#{c.name} <#{c.email}>" } subject "Contact form" headers { |c| { "X-Spam" => "True" } if c.honey_pot } attributes :name, :email, :message def author_email Author.find(self.author_id).email end end
21. José Valim @josevalim blog.plataformatec.com Issues
22. José Valim @josevalim blog.plataformatec.com Issues ✦ Lacks simplicity
23. José Valim @josevalim blog.plataformatec.com Issues ✦ Lacks simplicity ✦ Reduces programmer happiness
24. José Valim @josevalim blog.plataformatec.com NoDSL!
25. José Valim @josevalim blog.plataformatec.com From: GitHub <noreply@github.com> To: jose.valim@plataformatec.com.br Message-Id: <4bfe3e812c22fc17d@github.com> Subject: [GitHub] someone commented on a commit Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 MESSAGE BODY
26. José Valim @josevalim blog.plataformatec.com class ContactForm < MailForm::Base attributes :name, :email, :message def headers { :to => author_email, :from => "#{name} <#{email}>", :subject => "Contact form" } end def author_email Author.find(self.author_id).email end end
27. José Valim @josevalim blog.plataformatec.com It provides a nice DSL
28. José Valim @josevalim blog.plataformatec.com It relies on a simple contract
29. José Valim @josevalim blog.plataformatec.com
30. José Valim @josevalim blog.plataformatec.com Rack
31. José Valim @josevalim blog.plataformatec.com class RackApp def self.call(env) [200, { "Content-Type" => "text/html"}, ["Hello"]] end end
32. José Valim @josevalim blog.plataformatec.com RackApp = Rack::AppBuilder.new do |env| status 200 headers "Content-Type" => "text/html" body ["Hello"] after_return { # do something } end
33. José Valim @josevalim blog.plataformatec.com Rake and Thor
34. José Valim @josevalim blog.plataformatec.com task :process do # do some processing end namespace :app do task :setup do # do some setup # end end rake app:setup
35. José Valim @josevalim blog.plataformatec.com task :process do # do some processing end namespace :app do task :setup do # do some setup Rake::Task[:process].invoke end end rake app:setup
36. José Valim @josevalim blog.plataformatec.com class Default < Thor def process # do some processing end end class App < Thor def setup # do some setup # end end thor app:setup
37. José Valim @josevalim blog.plataformatec.com class Default < Thor def process # do some processing end end class App < Thor def setup # do some setup Default.new.process end end thor app:setup
38. José Valim @josevalim blog.plataformatec.com Rspec and Test::Unit
39. José Valim @josevalim blog.plataformatec.com # Rspec describe User do it "should be valid" do User.new(@attributes).should be_valid end end # Test::Unit class UserTest < Test::Unit::Case def test_user_validity assert User.new(@attributes).valid? end end
40. José Valim @josevalim blog.plataformatec.com A final story...
41. José Valim @josevalim blog.plataformatec.com class UsersController < ApplicationController def index @users = User.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @users } end end def show @user = User.find(params[:id]) respond_to do |format| format.html # show.html.erb format.xml { render :xml => @user } end end def new @user = User.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @user } end end def edit @user = User.find(params[:id]) end def create @user = User.new(params[:user]) respond_to do |format| if @user.save format.html { redirect_to(@user, :notice => 'User was successfully created.') } format.xml { render :xml => @user, :status => :created, :location => @user } else format.html { render :action => "new" } format.xml { render :xml => @user.errors, :status => :unprocessable_entity } end end end def update @user = User.find(params[:id]) respond_to do |format| if @user.update_attributes(params[:user]) format.html { redirect_to(@user, :notice => 'User was successfully updated.') } format.xml { head :ok } else format.html { render :action => "edit" } format.xml { render :xml => @user.errors, :status => :unprocessable_entity } end end end def destroy @user = User.find(params[:id]) @user.destroy respond_to do |format| format.html { redirect_to(users_url) } format.xml { head :ok } end end end Scaffold Controller
42. José Valim @josevalim blog.plataformatec.com class UsersController < ApplicationController restful! end
43. José Valim @josevalim blog.plataformatec.com class UsersController < ApplicationController restful! create do before { # do something before } success.flash "This is the message" end create.after do # do something after end end
44. José Valim @josevalim blog.plataformatec.com InheritedResources
45. José Valim @josevalim blog.plataformatec.com class UsersController < InheritedResources::Base def create # do something before flash[:success] = "This is the message" super # do something after end end
46. José Valim @josevalim blog.plataformatec.com Benefits
47. José Valim @josevalim blog.plataformatec.com Benefits ✦ Simple
48. José Valim @josevalim blog.plataformatec.com Benefits ✦ Simple ✦ Less code to maintain
49. José Valim @josevalim blog.plataformatec.com Benefits ✦ Simple ✦ Less code to maintain ✦ More time to focus on important features
50. José Valim @josevalim blog.plataformatec.com Benefits ✦ Simple ✦ Less code to maintain ✦ More time to focus on important features ✦ Just Ruby™
51. José Valim @josevalim blog.plataformatec.com
52. José Valim @josevalim blog.plataformatec.com ORM Callbacks
53. José Valim @josevalim blog.plataformatec.com # DSL class User < ActiveRecord::Base after_save :deliver_notification, :unless => :admin? end # NoDSL class User < ActiveRecord::Base def save(*) if super deliver_notification unless admin? end end end
54. José Valim @josevalim blog.plataformatec.com DSL or NoDSL?
55. José Valim @josevalim blog.plataformatec.com Thank you!
56. José Valim @josevalim blog.plataformatec.com Questions? Feedback? Opinions?
57. José Valim @josevalim blog.plataformatec.com blog twitter ID Questions? Feedback? Opinions?