Almost 15 slides in a little more than 15 minutes

A quick talk given at Ruby Montreal on December 16th, 2014.

Transcript

1. ALMOST 15 SLIDES IN A LITTLE MORE THAN 15 MINUTES
2. Equalities ==.eql?(equal?)
3. == or the Generic Equality
4. === or the Case Equality
5. eql? or the Hash Equality
6. equal? or the Generic Equality
7. Module#prepend Because we care about your ancestors
8. module Hello end class Example include Hello end Example.ancestors #=> [Example, Hello, …]
9. module Hello end class Example prepend Hello end Example.ancestors #=> [Hello, Example, …]
10. Useless Tip #1 String#split
11. $ “fox”.split("f") #=> ???
12. $ “fox”.split("f") #=> ["", "ox"]
13. $ “fox”.split("o") #=> ???
14. $ “fox”.split("o") #=> ["f", "x"]
15. $ “fox”.split("x") #=> ???
16. $ “fox”.split("o") #=> ["fo"]
17. Array#first What comes after five?
18. require ‘active_support' ary = (1…100).to_a ary.first ary.second ary.third ary.fourth ary.fifth …
19. require ‘active_support' ary = (1…100).to_a ary.first ary.second ary.third ary.fourth ary.fifth … ary.fourty_two
20. Post.where(…).forty_two
21. Post.where(…).forty_two! #=> RecordNotFound
22. Mysql Strict Mode Truncate ALL the data!
23. create_table :posts do |t| t.string “title”, limit: 100 end post = Post.create! do |post| post.title = “x” * 200 end post.title.length #=> 100
24. MySQL will truncate any too long varchar MySQL will ignore NOT NULL on updates
25. Now default in Rails 4 strict: true|false
26. There are 6 “wtf” in rails/rails Suck it rails. We have 19 of them in Shopify.
27. - 1 “shit” - 2 “python” - 3 “ninja” - 9 “suck” - 9 “ahoy” - 23 “unicorn”
28. … and 2337 “pirate”!
29. i_suck_and_my_tests_are_order_dependent! activesupport/lib/active_support/test_case.rb
30. There is a language called chicken I dare you to create a web server.
31. chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken chicken
32. function chicken(CHICKEN, Chicken) { Chicken &&( chicken. chicken =[, CHICKEN, CHICKEN = Chicken = chicken. $Chicken =-( CHICKEN ==( chicken. Chicken = Chicken ))], chicken. chicken [Chicken++] = chicken. chicken, chicken. CHICKEN = ++Chicken, chicken (--Chicken), chicken. $Chicken = ++Chicken, chicken. CHICKEN++ ); Chicken = chicken. Chicken [chicken. $Chicken++ ]; chicken. Chicken = CHICKEN? Chicken? '\012'== Chicken? chicken (++ CHICKEN, chicken. chicken [++ chicken. CHICKEN ]= CHICKEN - CHICKEN ): Chicken ==' '|'\015'== Chicken || (Chicken )== "c" & chicken. Chicken [chicken. $Chicken++ ]== "h" & chicken. Chicken [chicken. $Chicken++ ]== "i" & chicken. Chicken [chicken. $Chicken++ ]== "c" & chicken. Chicken [chicken. $Chicken++ ]== "k" & chicken. Chicken [chicken. $Chicken++ ]== "e" & chicken. Chicken [chicken. $Chicken++ ]== "n"&&++chicken. chicken [chicken. …
33. 1 chicken Pushes "chicken" onto the stack. 2 add Adds the two topmost groups of chickens. 3 fox Turns the topmost group of chickens into foxes. The foxes will subtract one chicken each from the second topmost group and eat them. Note that it is possible to end up with a negative amount of chickens. It may work arithmetically, but as it doesn't make sense it should be considered undefined behavior.
34. Even More Useless Tip #2 attr_accessor_with_default
35. class Person attr_accessor_with_default :age, 24 end $ x = Person.new $ x.a $ 24
36. class A attr_accessor_with_default :a, [] end $ x = A.new $ x.a << 1 $ [1] $ y = A.new $ y.a << 2 $ [1, 2]
37. Time for a Git Tip! Everybody knows `git log,` right?
38. $ git log ace9171 - Merge something 0b36a92 - Change something 0649bdc - Revert something
39. $ git log -G“hello world” file.rb ace9171 - Merge something 0b36a92 - Change something
40. $ git log -S“hello world” file.rb 0b36a92 - Change something
41. Seriously Useless Tip #3 Float::NAN
42. $ 0/0 #=> ???
43. $ 0/0 #=> ZeroDivisionError
44. $ 0.0/0 #=> ???
45. $ 0.0/0 #=> NaN
46. $ Float::NAN #=> NaN
47. $ nan = Float::NAN $ nan == nan #=> ???
48. $ nan = Float::NAN $ nan == nan #=> false
49. $ nan = Float::NAN $ [nan] == [nan] #=> ???
50. $ nan = Float::NAN $ [nan] == [nan] #=> true
51. $ nan = Float::NAN $ nan < 1.1 #=> ??? $ nan = Float::NAN $ nan > 1.1 #=> ??? $ nan = Float::NAN $ nan == 1.1 #=> ???
52. $ nan = Float::NAN $ nan < 1.1 #=> false $ nan = Float::NAN $ nan > 1.1 #=> false $ nan = Float::NAN $ nan == 1.1 #=> false
53. $ nan = Float::NAN $ [nan, 1.1].min #=> ???
54. $ nan = Float::NAN $ [nan, 1.1].min #=> ArgumentError: comparison of Float with Float failed
55. Timezones are crap Really, they are.
56. You live in Montreal GTM-05:00 Server in Moscow GTM+04:00 DB in GTM (default) GTM+00:00
57. You live in Montreal GTM-05:00 Server in Nepal GTM+05:45 DB in GTM (default) GTM+00:00
58. GTM+05:45
59. $ Time.now #=> ??? $ Time.zone.now #=> ??? $ Model.first.touch.updated_at #=> ??? $ Time.now.utc.in_time_zone(Time.now) #=> ???
60. $ Time.now #=> ??? $ Time.zone.now #=> ??? $ Model.first.touch.updated_at #=> ??? $ Time.now.utc.in_time_zone(Time.now) #=> ???
61. We shouldn’t have to care. the.endoftimezones.com/
62. Useless Tip #4 aliases
63. $ rails server #=> Bundler can't satisfy your Gemfile's dependencies.
64. $ bundle exec rails server #=> Run `bundle install` to install missing gems.
65. $ bundle install #=> Your bundle is complete! $ bundle exec rails server #=> Listening on 0.0.0.0:3000
66. $ bundle check #=> The Gemfile's dependencies are satisfied $ bundle check #=> Bundler can't satisfy your Gemfile's dependencies.
67. alias rs=“bundle check || bundle install && bundle exec rails server” $ rs #=> The Gemfile's dependencies are satisfied #=> Listening on 0.0.0.0:3000
68. Somewhat Useless Tip #5 Enumerable
69. [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5]
70. ary = [3, 1, 4, 1, 5, 9, 2, 6, 5, 3, 5] ary.chunk do |n| n.even? end #=> [false, [3, 1]] # [true, [4]] # [false, [1, 5, 9]] # [true, [2, 6]] # [false, [5, 3, 5]]
71. Not Sure If Useless Tip #6 Proc
72. Proc#=== Invokes the block with obj as the proc's parameter like #call.
73. case x when ->(n) { b.even? } then :foo when ->(n) { n.odd? } then :bar else :wtfs end
74. def code?(code) ->(r) { r.code == code } end case response when code?(200) then ”Cool!” when code?(400) then “Uhoh!” when code?(500) then “WTF?!” else “IMPOSSIBRU!!” end