Notes from a PHP Immigrant

While PHP (in its object-oriented form) and Ruby are similar in their overall strategy to solving problems, they have a number of key differences. Some of them are obvious and dramatic, while others are more subtle. In this talk, I cover how Ruby forced me to adjust my approach to writing software, and how it enabled me to better express my existing thoughts about code design.

Transcript

1. Notes from a PHP Immigrant Yitz Schaffer @YitzOfTheBits Vitals NYC.rb
2. My History 2008-
3. How I (think about) code and coding
4. PHP and Ruby def sum(a, b) a + b end function sum($a, $b) { return $a + $b; }
5. PHP and Ruby some_values = [ :foo, :bar, :baz ] $someValues = [ 'foo', 'bar', 'baz' ];
6. PHP and Ruby module Foo class Adder < MathOperation def initialize(initial_value) @initial_value = initial_value end def add_one @initial_value + 1 end end end Foo::Adder.new(4).add_one => 5 namespace Foo class Adder extends MathOperation { private $initialValue; public function __construct($initialValue) { $this->initialValue = $initialValue; } public function addOne() { return $this->initialValue + 1; } } (new \Foo\Adder(4))->addOne() => 5
7. PHP and Ruby [1, 2, 3].map { |x| x + 1 } array_map(function($x) { return $x + 1; }, [1, 2, 3]);
8. PHP: lots of things are not objects Ruby: everything is an object (?) 1 3.45 'abc' [$something] function bar() {} class Foo {} mysql_connect()
9. Metaprogramming!
10. Cool Metaprogramming Tools: AOP class Womper def expensive_operation(foo, bar) ... end end
11. Cool Metaprogramming Tools: AOP class Womper cache_method :expensive_operation def expensive_operation(foo, bar) ... end end
12. Cool Metaprogramming Tools: AOP class Womper cache_method :expensive_operation def expensive_operation(foo, bar) ... end end memory
13. Cool Metaprogramming Tools: AOP class Womper cache_method :expensive_operation def expensive_operation(foo, bar) ... end end Redis
14. Cool Metaprogramming Tools: AOP class Womper cache_method :expensive_operation def expensive_operation(foo, bar) ... end end LOLDB
15. Cool Metaprogramming Tools: AOP class Womper cache_method :expensive_operation def expensive_operation(foo, bar) ... end end LOLDB https://rubygems.org/gems/cache_method
17. Types! def render(Tweet p): Html ... end
18. interface Renderer { public function render(Tweet $tweet); } Types!
19. interface Renderer { public function render(Tweet $tweet); } interface Renderer def render(tweet) end Types!
20. abstract class Renderer { public function render(Tweet $tweet); } Types!
21. abstract class Renderer { public function render(Tweet $tweet); } class AbstractRenderer def render(tweet) fail NotImplementedError end end Types!
24. :it_is_still_a_string Symbol, i.e. Stringleton
25. irb(main):004:0> Array.instance_methods - Object.instance_methods Broad base of built-in methods
26. irb(main):004:0> Array.instance_methods - Object.instance_methods => [:to_a, :to_ary, :[], :[]=, :at, :fetch, :first, :last, :concat Broad base of built-in methods
27. irb(main):004:0> Array.instance_methods - Object.instance_methods => [:to_a, :to_ary, :[], : []=, :at, :fetch, :first, :last, :concat, :<<, :push, :pop, :shift, :unshift, :insert, :each, :each_index, :reverse_each, :length, :size, :empty?, :find_index, :index, :rind ex, :join, :reverse, :reverse!, :rotate, :rotate!, :sort, :sort!, :sort_by!, :collect, :collect!, :map, :map!, :select, :select!, :keep_if, :values_at, :delete, :delete_at, Broad base of built-in methods
28. irb(main):004:0> Array.instance_methods - Object.instance_methods => [:to_a, :to_ary, :[], : []=, :at, :fetch, :first, :last, :concat, :<<, :push, :pop, :shift, :unshift, :insert, :each, :each_index, :reverse_each, :length, :size, :empty?, :find_index, :index, :rind ex, :join, :reverse, :reverse!, :rotate, :rotate!, :sort, :sort!, :sort_by!, :collect, :collect!, :map, :map!, :select, :select!, :keep_if, :values_at, :delete, :delete_at, :delete_if, :reject, :reject!, :zip, :transpose, :replace, :clear, :fill, :include?, : slice, :slice!, :assoc, :rassoc, :+, :*, :-, :&, :| Broad base of built-in methods
29. irb(main):004:0> Array.instance_methods - Object.instance_methods => [:to_a, :to_ary, :[], : []=, :at, :fetch, :first, :last, :concat, :<<, :push, :pop, :shift, :unshift, :insert, :each, :each_index, :reverse_each, :length, :size, :empty?, :find_index, :index, :rind ex, :join, :reverse, :reverse!, :rotate, :rotate!, :sort, :sort!, :sort_by!, :collect, :collect!, :map, :map!, :select, :select!, :keep_if, :values_at, :delete, :delete_at, :delete_if, :reject, :reject!, :zip, :transpose, :replace, :clear, :fill, :include?, : slice, :slice!, :assoc, :rassoc, : +, :*, :-, :&, :|, :uniq, :uniq!, :compact, :compact!, :flatten, :flatten!, :count, :s huffle!, :shuffle, :sample, :cycle, :permutation, :combination, :repeated_permutation, :repeated_combination, :product, :take, :take_while, :drop, :drop_while, :bsearch Broad base of built-in methods
30. irb(main):004:0> Array.instance_methods - Object.instance_methods => [:to_a, :to_ary, :[], : []=, :at, :fetch, :first, :last, :concat, :<<, :push, :pop, :shift, :unshift, :insert, :each, :each_index, :reverse_each, :length, :size, :empty?, :find_index, :index, :rind ex, :join, :reverse, :reverse!, :rotate, :rotate!, :sort, :sort!, :sort_by!, :collect, :collect!, :map, :map!, :select, :select!, :keep_if, :values_at, :delete, :delete_at, :delete_if, :reject, :reject!, :zip, :transpose, :replace, :clear, :fill, :include?, : slice, :slice!, :assoc, :rassoc, : +, :*, :-, :&, :|, :uniq, :uniq!, :compact, :compact!, :flatten, :flatten!, :count, :s huffle!, :shuffle, :sample, :cycle, :permutation, :combination, :repeated_permutation, :repeated_combination, :product, :take, :take_while, :drop, :drop_while, :bsearch, :pa ck, :entries, :sort_by, :grep, :find, :detect, :find_all, :flat_map, :collect_concat, :inject, :reduce, :partition, :group_by, :all?, :any?, :one?, :none?, :min, :max, :min max, :min_by, :max_by, :minmax_by, :member?, :each_with_index, :each_entry, :each_slic e, :each_cons, :each_with_object, :chunk, :slice_before, :lazy] Broad base of built-in methods
32. Built-in method aliases
33. Built-in method aliases
34. Built-in method aliases
35. function blow_it_up($data) { $data['foo'] = 'BOOM'; return $data; } $a = ['foo' => 'bar']; $b = blow_it_up($a); $a['foo'] // 'bar' PHP: pass-by-copy for non-objects
36. def blow_it_up(data) data[:foo] = 'BOOM' data end a = {foo: 'bar'} b = blow_it_up(a) a[:foo] => 'BOOM' Ruby: regular ol' pass-by-value
37. def blow_it_up(data) data[:foo] = 'BOOM' data end a = {foo: 'bar'} b = blow_it_up(a) a[:foo] => 'BOOM' Ruby: regular ol' pass-by-value
38. [ 'baz', 'quux' ] { foo: 'bar' } Lists and Maps: Array, Hash, array()
39. array( 'foo' => 'bar' ) array( 'baz', 'quux' ) Lists and Maps: Array, Hash, array()
40. [1, 2, 3, 4, 5].select { |x| x.even? } Filtering Lists
41. [1, 2, 3, 4, 5].select { |x| x.even? } => [2, 4] Filtering Lists
42. array( 1, 2, 3, 4, 5 ) Filtering Lists
43. array( 0 => 1, 1 => 2, 2 => 3, 3 => 4, 4 => 5 ) Filtering Lists
44. array( 0 => 1, 1 => 2, 2 => 3, 3 => 4, 4 => 5 ) Filtering “Lists” i.e. Hashes
45. array( 0 => 1, 1 => 2, 2 => 3, 3 => 4, 4 => 5 ) apply filter… function($x) { return $x % 2 == 0; } Filtering “Lists” i.e. Hashes
46. array( // 0 => 1, 1 => 2, // 2 => 3, 3 => 4, // 4 => 5 ) apply filter… Filtering “Lists” i.e. Hashes function($x) { return $x % 2 == 0; }
47. array( 1 => 2, 3 => 4 ) apply filter… Filtering “Lists” i.e. Hashes
48. array( 1 => 2, 3 => 4 ) Filtering “Lists” i.e. Hashes
49. array( 1 => 2, 3 => 4 )[0] PHP Notice: Undefined offset: 0 Filtering “Lists” i.e. Hashes
50. array( 1 => 2, 3 => 4 )[0] PHP Notice: Undefined offset: 0 Filtering “Lists” i.e. Hashes array_values(array( 1 => 2, 3 => 4 ))[0] => 2
51. function calculateScore(factors) { // ... return $aCalculatedScore } Instructions vs. Definitions def score # ... a_calculated_score end
52. class Person { public function renderSalutation() { $fullName = ''; $fullName .= $this->firstName(); $fullName .= ' '; $fullName .= $this->lastName(); return $fullName . ', ' . $this->renderTitle(); } } Variable and Method Names
53. class Person { public function renderSalutation() { // extracted method from up here return $fullName . ', ' . $this->renderTitle(); } public function fullName() { $fullName = ''; $fullName .= $this->firstName(); $fullName .= ' '; $fullName .= $this->lastName(); return $fullName; } } Variable and Method Names
54. class Person { public function renderSalutation() { return $this->fullName() . ', ' . $this->renderTitle(); } public function fullName() { $fullName = ''; $fullName .= $this->firstName(); $fullName .= ' '; $fullName .= $this->lastName(); return $fullName; } } Variable and Method Names
55. class Person def renderSalutation full_name = '' full_name += full_name + first_name full_name += ' '; full_name += last_name full_name + ', ' + renderTitle end end Variable and Method Names
56. class Person def renderSalutation full_name + ', ' + renderTitle end def full_name full_name = '' full_name += full_name + first_name full_name += ' '; full_name += last_name end end Variable and Method Names
57. > Array(nil) => [] > Array([]) => [] > Array('foo') => ['foo'] > Array(['foo']) => ['foo'] Data Type Coercion
58. > Hash(nil) => {} > Hash(foo: 'bar') => {:foo=>'bar'} Data Type Coercion
59. vowel = Proc.new do |x| ['a', 'e', 'i', 'o', 'u'].include?(x.downcase) end Higher-order syntax sugar
60. vowel = Proc.new do |x| ['a', 'e', 'i', 'o', 'u'].include?(x.downcase) end 'what is my first vowel?'.split('').find { |letter| vowel.call(letter) } => 'a' Higher-order syntax sugar
61. vowel = Proc.new do |x| ['a', 'e', 'i', 'o', 'u'].include?(x.downcase) end 'what is my first vowel?'.split('').find { |letter| vowel.call(letter) } 'what is my first vowel?'.split('').find(&vowel) => 'a' Higher-order syntax sugar
62. > ['foo', 'bar'].map(&:reverse) Higher-order syntax sugar
63. > ['foo', 'bar'].map(&:reverse) => ["oof", "rab"] Higher-order syntax sugar
64. > ['foo', 'bar'].map(&:reverse) => ["oof", "rab"] Higher-order syntax sugar > p = :reverse.to_proc => #<Proc:0x007fb4411bfec0> > p.call('jim') => "mij"
65. > { Date.new => [1,2,3] } => { #<Date:0x007fc8609c6a78> => [1,2,3] } Arbitrary Object as Hash key
66. matching_object_for(params) do |obj| obj.do_something end Indirection of block control (evil)
67. matching_object_for(params) do |obj| obj.do_something end def matching_object_for(params) obj = Model.find(params[:id]) yield obj unless obj.meaning == 42 end Indirection of block control (evil)
68. class Whatever def initialize @state = SomeState.new end def foogle with_alternate_state do calculated_value end end def with_alternate_state original_state = @state.dup @state.mutate! yield @state = original_state end end Block as state sandbox (evil)
69. Better Specs { rspec guidelines with ruby } http://betterspecs.org/
70. http://cleancoders.com/episode/clean-code-episode-20/show
71. Notes from a PHP Immigrant Yitz Schaffer @YitzOfTheBits Vitals NYC.rb