Make Up Your Own "Hello, World!"

We all love Ruby. Maybe we’ve only been paid to write code in Ruby (and maybe JavaScript). But there are so many other languages out there, and they all have strengths, weaknesses, and very different communities surrounding them.
Let’s talk about language exploration. We’ll discuss how to learn a new language, considerations when introducing things to production, and come up with some ideas for Ruby and it’s ecosystem. Plan on dipping your toes in Elixir, Go, Haskell, Rust, and Scala during the session.

Transcript

1. Make up your own "Hello, World!" @justincampbell
2. Learn (verb) 4 gain or acquire knowledge of or skill in (something) by study, experience, or being taught 4 commit to memory 4 become aware of (something) by information or from observation
5. How?
8. You need a project
9. I need a project
10. HTTP
11. Writes
12. State
13. Testing
14. TDD
15. TDD
16. Goals 4 HTTP 4 Writes 4 Shared State 4 TDD
17. 4 Billboard 4 Blog 4 Chat 4 Counter 4 Dice 4 Stats 4 Storage 4 Twitter 4 URL Shortener
18. URL Shortener
19. Shorten POST / "url=http://justincampbell.me" -------> ,---------, |Shortener| 201 Created <--------------------------------- '---------' /1
20. Expand GET /1 --------------------------------------> ,---------, |Shortener| 301 Redirect <-------------------------------- '---------' Location: http://justincampbell.me
21. Missing GET /54321 ----------------------------------> ,---------, |Shortener| 404 Not Found <------------------------------- '---------'
22. Ruby
23. # Ruby post '/' do token = shortener.shorten(params[:url]) [201, "/#{token}"] end
24. # Ruby post '/' do token = shortener.shorten(params[:url]) [201, "/#{token}"] end get '/:token' do |token| full_url = shortener.expand(token) halt 404 unless full_url redirect full_url end
25. # Ruby class Shortener def shorten(url) token = id_generator.next.to_s urls[token] = url token end def expand(token) urls[token] end end
26. # Ruby class Shortener def id_generator @id_generator ||= (1..Float::INFINITY).enum_for end def urls @urls ||= Hash.new end end
27. # Ruby def shortener Shortener.instance end class Shortener def self.instance @instance ||= new end end
28. Thread-Safe?
30. Clojure
31. ; Clojure (def token (atom 0))
32. ; Clojure (def token (atom 0)) (defn next-token [] (swap! token inc))
33. ; Clojure (def token (atom 0)) (defn next-token [] (swap! token inc)) (next-token) ; => 1
34. ; Clojure (def token (atom 0)) (defn next-token [] (swap! token inc)) (next-token) ; => 1 (next-token) ; => 2
36. # Ruby def shorten(url) token = id_generator.next.to_s urls[token] = url token end
37. # Ruby def shorten(url) token = id_generator.next.to_s urls[token] = url token end {- Haskell -} shorten :: Url -> Token
38. # Ruby def shorten(url) token = id_generator.next.to_s urls[token] = url token end {- Haskell -} shorten :: Url -> Token {- shorten is a function from a Url to a Token -}
39. # Ruby def shorten(url) token = id_generator.next.to_s urls[token] = url token end {- Haskell -} type Token = String type Url = String shorten :: Url -> Token
40. # Ruby def shorten(url) token = id_generator.next.to_s urls[token] = url token end {- Haskell -} type Token = String type Url = String shorten :: Url -> Token shorten url = token where {- increment token, store url -}
41. {- Haskell -} type Token = String type Url = String shorten :: Url -> Token
42. {- Haskell -} type Token = String type Url = String shorten :: Url -> World -> Token
43. {- Haskell -} type Token = String type Url = String shorten :: Url -> World -> World
44. {- Haskell -} type Token = String type Url = String data World = World { id :: Int, urls :: Map Token Url } shorten :: Url -> World -> World
45. {- Haskell -} type Token = String type Url = String data World = World { id :: Int, urls :: Map Token Url } shorten :: Url -> World -> World shorten url world = newWorld where nextId = succ $ _id world token = show nextId newUrls = insert token url $ _urls world newWorld = World nextId newUrls
46. {- Haskell -} type Token = String type Url = String data World = World { id :: Int, urls :: Map Token Url } shorten :: Url -> World -> World
47. {- Haskell -} type Token = String type Url = String data World = World { id :: Int, urls :: Map Token Url } shorten :: Url -> World -> World expand :: Token -> World -> Maybe Url
48. Nim
49. # Nim type Token = string type Url = string var id = 0 var urls = newTable[Token, Url]() proc shorten*(url: Url): Token = id += 1 let token = intToStr(id) urls[token] = url return token proc expand*(token: Token): Url = if hasKey(urls, token): return urls[token]
50. {- Haskell -} expand :: Token -> World -> Maybe Url # Nim proc expand*(token: Token): Url = # ...
51. # Nim proc expand*(token: Token): Url = # ...
52. # Nim proc expand*(token: Token): Url = # ... shorten("google.com") # => "1"
53. # Nim proc expand*(token: Token): Url = # ... shorten("google.com") # => "1" expand("1") # => "google.com"
54. # Nim proc expand*(token: Token): Url = # ... shorten("google.com") # => "1" expand("1") # => "google.com" expand("54321") # => nil
56. nil
57. NoMethodError: undefined method `name' for nil:NilClass
58. NoMethodError: undefined method `name' for nil:NilClass Type Error
59. Go
60. // Go url, err := shortener.expand(token); if err != nil { http.NotFound(response, request); } http.Redirect(response, request, url, 301);
61. // Go url, err := shortener.expand(token); // if err != nil { // http.NotFound(response, request); // } http.Redirect(response, request, url, 301);
62. // Go url, err := shortener.expand(token); // if err != nil { // http.NotFound(response, request); // } http.Redirect(response, request, url, 301); // ???
63. In two weeks, Im headed to India to give a keynote at a Go Conference. Last year this time, I was like, "why do I need a GOROOT and GOPATH?" - Bryan Lyles
64. # Ruby get '/:token' do |token| url = shortener.expand(token) halt 404 unless url redirect url end
65. # Ruby get '/:token' do |token| begin url = shortener.expand(token) redirect url rescue # ??? halt 404 end end
66. Elixir/Erlang
67. # Elixir {:ok, url} = Shortener.Core.expand(conn.params[:token])
68. # Elixir {:ok, url} = Shortener.Core.expand(conn.params[:token]) # ** (MatchError) no match of right hand side value: # {:error, "Token not found"}
69. # Elixir case Shortener.Core.expand(conn.params[:token]) do {:ok, url} -> redirect conn, to: url _ -> conn.send 404, "Not found" end
70. # Ruby case url = shortener.expand(token) when String redirect url when NilClass halt 404 end
71. # Ruby case result = shortener.expand(token) when result.success? redirect result.value else halt 404 end
72. # Ruby def halve(number) number / 2.0 end halve 5 # => 2.5 halve "5" # strings don't respond to `/`
76. Embrace Conventions
78. " Clojure Plug 'guns/vim-clojure-static' Plug 'guns/vim-sexp' Plug 'tpope/vim-classpath' Plug 'tpope/vim-fireplace' Plug 'tpope/vim-leiningen' Plug 'tpope/vim-sexp-mappings-for-regular-people' " CoffeeScript Plug 'kchmck/vim-coffee-script' " Elixir Plug 'elixir-lang/vim-elixir' " Go Plug 'fatih/vim-go' " Haskell Plug 'dag/vim2hs' Plug 'eagletmt/ghcmod-vim' Plug 'shougo/vimproc.vim' " JavaScript Plug 'pangloss/vim-javascript' " Nim Plug 'zah/nimrod.vim'
79. " OCaml Plug 'ocamlpro/ocp-indent' Plug 'the-lambda-church/merlin' " PureScript Plug 'raichoo/purescript-vim' " Ruby Plug 'ecomba/vim-ruby-refactoring' Plug 'hwartig/vim-seeing-is-believing' Plug 'jgdavey/vim-blockle' Plug 'tpope/vim-rails' Plug 'tpope/vim-rake' Plug 'vim-ruby/vim-ruby' " Rust Plug 'wting/rust.vim' " Scala Plug 'derekwyatt/vim-scala' " Shell Plug 'markcornick/vim-bats' Plug 'rosstimson/bats.vim' " Thrift Plug 'solarnz/thrift.vim'
80. make
81. make default: deps test deps: which bundle || gem install bundler bundle check || bundle install test: bundle exec rspec spec/
82. Why?
83. New Perspective
84. "If you do what you've always done, you'll get what you've always gotten" - Henry Ford
85. Language Matters
86. The principle of linguistic relativity holds that the structure of a language affects the ways in which its respective speakers conceptualize their world, i.e. their world view, or otherwise influences their cognitive processes. http://en.wikipedia.org/wiki/Linguistic_relativity
87. Make you a better Rubyist
88. @ work
89. Hiring Filters: Write your app in Rails, and enter the hiring fracas. Or, use Haskell or Clojure and hire better people with less competition. — Ben Orenstein twitter.com/r00k/status/563821546016636928
90. Bored People Quit - Michael Lopp randsinrepose.com/archives/bored-people-quit
91. Thoughts + Ideas for Ruby:
92. RSpec is hard
93. # Ruby describe User do subject(:user) { described_class.new(first_name, last_name) } let(:first_name) { "Justin" } let(:last_name) { "Campbell" } it "concatenates a full name" do expect(user.full_name).to start_with(first_name) expect(user.full_name).to end_with(last_name) end end
94. # Ruby describe User do def test_full_name user = User.new("Justin", "Campbell") assert_equal "Justin Campbell", user.full_name end end
95. Outside-in? Inside-out?
96. Inside-out? Outside-in?
97. $ sbt test [info] Set current project ... [info] Run completed in 397 milliseconds. [info] Total number of tests run: 1 [info] Suites: completed 1, aborted 0 [info] Tests: succeeded 1, failed 0, canceled 0, ignored 0, pending 0 [info] All tests passed. [success] Total time: 2 s
98. $ sbt ~test [info] Set current project ... [info] Run completed in 397 milliseconds. [info] Total number of tests run: 1 [info] Suites: completed 1, aborted 0 [info] Tests: succeeded 1, failed 0, canceled 0, ignored 0, pending 0 [info] All tests passed. [success] Total time: 2 s 1. Waiting for source changes... (press enter to interrupt)
99. $ rake ~test
100. $ rake ~test task :test do |t| t.watch /^.+_test\.rb$/ end
101. $ lein test Retrieving lein-exec/lein-exec/0.3.1/lein-exec-0.3.1.pom from clojars Retrieving lein-exec/lein-exec/0.3.1/lein-exec-0.3.1.jar from clojars Retrieving org/clojure/clojure/1.6.0/clojure-1.6.0.pom from central Retrieving org/sonatype/oss/oss-parent/7/oss-parent-7.pom from central Retrieving org/clojure/tools.nrepl/0.2.3/tools.nrepl-0.2.3.pom from central [...] lein test ... Ran 1 tests containing 1 assertions. 0 failures, 0 errors.
102. $ bundle exec rspec Could not find rspec-5.0.0 in any of the sources Run `bundle install` to install missing gems.
103. $ bundle exec rspec The following gems are missing * rspec (3.0.0) Installing rspec 3.0.0 Bundle complete! ............... Finished in 0.16548 seconds 15 examples, 0 failures
104. # Ruby class Animal def initialize(type) @type = type end end Animal.new(:cat) # => #<Animal @type=:cat>
105. # Ruby class Animal def initialize(type) @type = type end end Animal(:cat) # NoMethodError
106. # Ruby require 'newk/everything' class Animal def initialize(type) @type = type end end Animal(:cat) # => #<Animal @type=:cat>
108. "Learn a language a year"
109. Too long + Too short
110. Start Small
111. Pick a Project
112. URL Shortener
113. Conway's Game of Life en.wikipedia.org/wiki/Conway's_Game_of_Life
114. Which Language First?
115. Haskell
116. Clojure
117. Go
118. Fun + Community
119. Fun! Compiler + Readability
120. Community! Adoption + Friendliness
121. Resources:
123. learnxinyminutes.com
124. ! github.com/kata-seeds
125. Share your Excitement
126. Have Fun
127. Dude, sucking at something is the first step towards being sorta good at something - Jake, Adventure Time
128. Thanks! @justincampbell