why everyone like ruby
TRANSCRIPT
Почему все так любят ruby?
Юрий Хрусталев, Deep Refactoring, 28.09.2016
О чем это?● О стереотипах
● ruby - удобно, элегантно, просто, понятно
● ruby - инструмент Силиконовой Долины
● ruby лучше, чем python*
* конечно нет
Почему?● Я недавно начал писать на ruby on rails
● До этого я 4 года писал на python
● Wat? https://www.destroyallsoftware.com/talks/wat
Плохая Махачкала Ruby
class Foo def initialize puts 'hi' endend
class Foo def initialize puts 'hi' endend
Foo.new# А почему метод initialize, не new?
irb(main):001:0> bool
irb(main):001:0> boolNameError: undefined local variable or method `bool' for main:Object from (irb):1 from /usr/bin/irb:12:in `<main>'
# Ок, это же язык с продвинутым ООП
irb(main):002:0> "".to_b
irb(main):002:0> "".to_bNoMethodError: undefined method `to_b' for "":String from (irb):1 from /usr/bin/irb:12:in `<main>' # Где метод у объекта, это же ООП язык?
irb(main):003:0> !!""
irb(main):003:0> !!""(irb):2: warning: string literal in condition=> true
# Почему warning?# Нужно сравнивать через ==
irb(main):003:0> !!""(irb):2: warning: string literal in condition=> true
# Почему warning?# Нужно сравнивать через ==# Почему оно true?
irb(main):004:0> !!{}
irb(main):004:0> !!{}=> true
irb(main):004:0> !!{}=> trueirb(main):005:0> !![]
irb(main):004:0> !!{}=> trueirb(main):005:0> !![]=> true
irb(main):004:0> !!{}=> trueirb(main):005:0> !![]=> trueirb(main):006:0> !!Object.new
irb(main):004:0> !!{}=> trueirb(main):005:0> !![]=> trueirb(main):006:0> !!Object.new=> true
# Ничто не false, кроме false/nil/собственного ==
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> true
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> true
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> trueirb(main):003:0> nil.blank?
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> trueirb(main):003:0> nil.blank?=> true
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> trueirb(main):003:0> nil.blank?=> trueirb(main):004:0> 0.blank?
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> trueirb(main):003:0> nil.blank?=> trueirb(main):004:0> 0.blank?=> false
# Ruby? Это такой DSL для написания Rails-приложений?
irb(main):001:0> require 'active_support/all'=> trueirb(main):002:0> [].blank?=> trueirb(main):003:0> nil.blank?=> trueirb(main):004:0> 0.blank?=> false# нормально же общались
# Python
>>> arr = [1, 2, 3]>>> map(str, arr)["1", "2", "3"]
irb(main):001:0> arr = [1, 2, 3]=> [1, 2, 3]
irb(main):001:0> arr = [1, 2, 3]=> [1, 2, 3]irb(main):002:0> arr.map {|item| item.to_s}=> ["1", "2", "3"]
irb(main):001:0> arr = [1, 2, 3]=> [1, 2, 3]irb(main):002:0> arr.map {|item| item.to_s}=> ["1", "2", "3"]irb(main):003:0> arr.map(&:to_s)=> ["1", "2", "3"]
# &: - указатель на имя метода
irb(main):001:0> arr = ["1", "2", "3"]=> ["1", "2", "3"]
irb(main):001:0> arr = ["1", "2", "3"]=> ["1", "2", "3"]irb(main):002:0> arr.map(&:String.new)
irb(main):001:0> arr = ["1", "2", "3"]=> ["1", "2", "3"]irb(main):002:0> arr.map(&:String.new)NoMethodError: undefined method `new' for :String:Symbol from (irb):26 from /usr/bin/irb:12:in `<main>'
# это было бы слишком элегантно
irb(main):003:0> arr.map(&String.method(:new))
irb(main):003:0> arr.map(&String.method(:new))=> ["1", "2", "3"]
# это удобно
# chain.rbx = ' foo bar ' .strip .split(' ')puts x.to_s
# chain.rbx = ' foo bar ' .strip .split(' ')puts x.to_s
irb(main):001:0> load './chain.rb'[1, 2]=> nil
# chain.rbx = ' foo bar ' #.strip .split(' ')puts x.to_s
irb(main):001:0> load './chain.rb'SyntaxError: /tmp/code.rb:4: syntax error, unexpected '.', expecting end-of-input .split(' ')^ from (irb):15:in `load'from (irb):15from /usr/bin/irb:12:in `<main>'
# даже python так не делает
irb(main):001:0> String.new "x"
irb(main):001:0> String.new "x"=> "x"
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")=> "x"
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")=> "x"irb(main):003:0> String.new( "x" )
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")=> "x"irb(main):003:0> String.new( "x" )=> "x"
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")=> "x"irb(main):003:0> String.new( "x" )=> "x"irb(main):004:0> String.new ("x")
irb(main):001:0> String.new "x"=> "x"irb(main):002:0> String.new("x")=> "x"irb(main):003:0> String.new( "x" )=> "x"irb(main):004:0> String.new ("x")=> "x"
irb(main):005:0> [String.new("x")]
irb(main):005:0> [String.new("x")]=> ["x"]
irb(main):005:0> [String.new("x")]=> ["x"]irb(main):006:0> [String.new ("x")]
irb(main):005:0> [String.new("x")]=> ["x"]irb(main):006:0> [String.new ("x")]SyntaxError: (irb):25: syntax error, unexpected ( arg, expecting ']'[String.new ("x")]^ (irb):25: syntax error, unexpected ']', expecting end-of-inputfrom /usr/bin/irb:12:in `<main>'# Пробелы
irb(main):001:0> %w(rm -rf /home)
irb(main):001:0> %w(rm -rf /home)=> ["rm", "-rf", "/home"]
irb(main):001:0> %w(rm -rf /home)=> ["rm", "-rf", "/home"]irb(main):002:0> %i(rm -rf /home)
irb(main):001:0> %w(rm -rf /home)=> ["rm", "-rf", "/home"]irb(main):002:0> %i(rm -rf /home)=> [:rm, :"-rf", :"/home"]
irb(main):001:0> %w(rm -rf /home)=> ["rm", "-rf", "/home"]irb(main):002:0> %i(rm -rf /home)=> [:rm, :"-rf", :"/home"]irb(main):003:0> %x(rm -rf /home)
irb(main):001:0> %w(rm -rf /home)=> ["rm", "-rf", "/home"]irb(main):002:0> %i(rm -rf /home)=> [:rm, :"-rf", :"/home"]irb(main):003:0> %x(rm -rf /home)=> ""
# это еще хорошо у меня OSX
irb(main):001:0> {foo: 1}=> {:foo=>1}
irb(main):001:0> {foo: 1}=> {:foo=>1}irb(main):002:0> {:foo => 1}=> {:foo=>1}
irb(main):001:0> {foo: 1}=> {:foo=>1}irb(main):002:0> {:foo => 1}=> {:foo=>1}irb(main):003:0> {"foo" => 1}=> {"foo"=>1}
irb(main):005:0> {:foo => 1}["foo"]
irb(main):005:0> {:foo => 1}["foo"]=> nil
irb(main):005:0> {:foo => 1}["foo"]=> nilirb(main):006:0> {:foo => 1}["foo".to_sym]
irb(main):005:0> {:foo => 1}["foo"]=> nilirb(main):006:0> {:foo => 1}["foo".to_sym]=> 1
# зато метод без скобок вызван
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}irb(main):003:0> h["foo"]
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}irb(main):003:0> h["foo"]=> 1
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}irb(main):003:0> h["foo"]=> 1irb(main):004:0> h[:foo]
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}irb(main):003:0> h["foo"]=> 1irb(main):004:0> h[:foo]=> 1
# доступно только в rails
irb(main):001:0> h = {:foo => 1}=> {:foo=>1}irb(main):002:0> h = h.with_indifferent_access=> {"foo"=>1}irb(main):003:0> h["foo"]=> 1irb(main):004:0> h[:foo]=> 1
# доступно только в rails# ruby DSL для rails
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'end
foo do |value| puts valueend
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'end
foo do |value| puts valueend
> open resource4142close resource
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'end
foo do |value| puts value breakend
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'end
foo do |value| puts value breakend
> open resource41
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'enddef has_answer? foo do |value| return true if value == 42 endendputs has_answer?
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'enddef has_answer? foo do |value| return true if value == 42 endendputs has_answer?
> open resourcetrue
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'enddef has_answer? rc = false foo {|value| rc = true if value == 42} rcendputs has_answer?
def foo(&block) puts 'open resource' [*41..42].each &block.method(:call) puts 'close resource'enddef has_answer? rc = false foo {|value| rc = true if value == 42} rcendputs has_answer?
> open resourceclose resourcetrue
module Foo def bar puts 'hi' endend
irb(main):009:0* Foo.bar
module Foo def bar puts 'hi' endend
irb(main):009:0* Foo.barNoMethodError: undefined method `bar' for Foo:Module from (irb):9 from /usr/bin/irb:12:in `<main>'
module Foo module_function def bar puts 'hi' endend
irb(main):010:0* Foo.barhi
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::bar
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::barhi=> nil
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::barhi=> nilirb(main):097:0> Foo::BAZ
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::barhi=> nilirb(main):097:0> Foo::BAZ=> "hey"
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::barhi=> nilirb(main):097:0> Foo::BAZ=> "hey"irb(main):098:0> Foo.baz
module Foo BAZ = 'hey' module_function def bar puts 'hi' endend
irb(main):096:0> Foo::barhi=> nilirb(main):097:0> Foo::BAZ=> "hey"irb(main):098:0> Foo.bazNoMethodError: undefined method `baz' for Foo:Module from (irb):98 from /usr/bin/irb:12:in `<main>'# почему нет?
В качестве заключения, что с популярностью ruby?
Спасибо за внимание