Ruby 程式語言簡介

Ruby 20

[email protected]/4/17

OSDC.TW

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? a.k.a. ihower

http://ihower.idv.tw/blog/ twitter: ihower

2006 Ruby () Rails Developer

http://handlino.com http://registrano.com

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Ruby?

Yukihiro Matsumoto, a.k.a. Matz

Lisp, Perl, Smalltalk Happy

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# "UPPER"puts "upper".upcase # -5 puts -5.abs # "Ruby Rocks!" 5.times do puts "Ruby Rocks!"end

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Methodsdef end

def say_hello(name) result = "Hi, " + name return resultend

puts say_hello('ihower')# Hi, ihower

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Class class Greeter

def initialize(name) @name = name end def say(word) puts "#{phrase}, #{@name}" end end

g1 = Greeter.new("ihower")g2 = Greeter.new("ihover") g1.say("Hello") # Hello, ihowerg2.say("Hello") # Hello, ihover

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Class ()class Greeter

@@name = ihower def self.say puts @@name end end

Greeter.say # Hello, ihower

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Arraya = [ 1, "cat", 3.14 ]

puts a[0] # 1puts a.size # 3

a[2] = nilputs a.inspect # [1, "cat", nil]

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Hash

config = { "foo" => 123, "bar" => 456 }

puts config["foo"] # 123

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Symbols

config = { :foo => 123, :bar => 456 }

puts config[:foo] # 123

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If

if account.total > 100000 puts "large account"elsif account.total > 25000 puts "medium account"else puts "small account"end

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If

if account.total > 100000 puts "large account"elsif account.total > 25000 puts "medium account"else puts "small account"end

Perl Style

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Case

case name when "John" puts "Howdy John!" when "Ryan" puts "Whatz up Ryan!" else puts "Hi #{name}!"end

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false nil

puts "not execute" if nilputs "not execute" if false

puts "execute" if true # executeputs "execute" if # execute (JavaScript)puts "execute" if 0 # execute (C)puts "execute" if 1 # executeputs "execute" if "foo" # executeputs "execute" if Array.new # execute

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Regular Expressions Perl

# phone = "123-456-7890" if phone =~ /(\d{3})-(\d{3})-(\d{4})/ ext = $1 city = $2 num = $3end

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code block closure

{ puts "Hello" } # block

do puts "Blah" # block puts "Blah"end

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code block(iterator)

# peoplepeople = ["David", "John", "Mary"]people.each do |person| puts personend # 5.times { puts "Ruby rocks!" }

# 1.upto(9) { |x| puts x }

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code block(iterator)

# peoplepeople = ["David", "John", "Mary"]people.each do |person| puts personend # 5.times { puts "Ruby rocks!" }

# 1.upto(9) { |x| puts x }

while, until, for

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code block

# a = [ "a", "b", "c", "d" ]b = a.map {|x| x + "!" } # ["a!", "b!", "c!", "d!"]

# [1,2,3].find_all{ |x| x % 2 == 0 }# [2]

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code block

# a = [ "a", "b", "c" ]a.delete_if {|x| x >= "b" }# ["a"]

# [2,1,3].sort! { |a, b| b a }# ["3",2,1]

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code block functional programming fu?

# (5..10).inject {|sum, n| sum + n }

# find the longest wordlongest = ["cat", "sheep", "bear" }.inject do |memo, word| ( memo.length > word.length )? memo : wordend

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code block

file = File.new("testfile", "r")# ...file.close

File.open("testfile", "r") do |file| # ...end#

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Yield yield code block

# def call_block puts "Start" yield yield puts "End"end call_block { puts "Blocks are cool!" }# # "Start" # "Blocks are cool!" # "Blocks are cool!" # "End"

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code blockdef call_block yield(1) yield(2) yield(3)end call_block { |i| puts "#{i}: Blocks are cool!"}# # "1: Blocks are cool!" # "2: Blocks are cool!"# "3: Blocks are cool!"

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Proc object code block

def call_block(&block) block.call(1) block.call(2) block.call(3)end call_block { |i| puts "#{i}: Blocks are cool!" }

# proc objectproc_1 = Proc.new { |i| puts "#{i}: Blocks are cool!" }proc_2 = lambda { |i| puts "#{i}: Blocks are cool!" }

call_block(&proc_1)call_block(&proc_2)

# # "1: Blocks are cool!" # "2: Blocks are cool!"# "3: Blocks are cool!"

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Module Mixinsmodule Debug def who_am_i? "#{self.class.name} (\##{self.object_id}): #{self.to_s}" endend

class Foo include Debug # Mixin # ...end

class Bar include Debug include AwesomeModule # ...end

ph = Foo.new("12312312")et = Bar.new("78678678")ph.who_am_i? # "Foo (#330450): 12312312"et.who_am_i? # "Bar (#330420): 78678678"

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Module Mixinsmodule Debug def who_am_i? "#{self.class.name} (\##{self.object_id}): #{self.to_s}" endend

class Foo include Debug # Mixin # ...end

class Bar include Debug include AwesomeModule # ...end

ph = Foo.new("12312312")et = Bar.new("78678678")ph.who_am_i? # "Foo (#330450): 12312312"et.who_am_i? # "Bar (#330420): 78678678"

Ruby Module

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(duck typing)

# class Duck def quack puts "quack!" endend # ()class Mallard def quack puts "qwuaacck!! quak!" endend

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Class Type

birds = [Duck.new, Mallard.new, Object.new]

# ()birds.each do |duck| duck.quack if duck.respond_to? :quackend

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Class Type

birds = [Duck.new, Mallard.new, Object.new]

# ()birds.each do |duck| duck.quack if duck.respond_to? :quackend

OOP!

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Metaprogramming

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define_method

class Dragon define_method(:foo) { puts "bar" }

['a','b','c','d','e','f'].each do |x| define_method(x) { puts x } endend

dragon = Dragon.newdragon.foo # "bar"dragon.a # "a"dragon.f # "f"

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Domain-Specific Language

class Firm < ActiveRecord::Base has_many :clients has_one :account belongs_to :conglomorateend

# has_many AciveRecord class method# Firm instance methods

firm = Firm.find(1)firm.clientsfirm.clients.sizefirm.clients.buildfirm.clients.destroy_all

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Method Missingclass Proxy def initialize(object) @object = object end def method_missing(symbol, *args) @object.send(symbol, *args) endend object = ["a", "b", "c"]proxy = Proxy.new(object)puts proxy.first # Proxy first method_missing "a"

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Introspection ()

# Object.methods=> ["send", "name", "class_eval", "object_id", "new", "singleton_methods", ...] # Object.respond_to? :name=> true

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Ruby on Rails 5

[email protected]/4/17

OSDC.TW

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Rails? Web

database-backed

Model-View-Control () Ruby

AjaxORM (object-relational-mapping)

2004 David Heinemeier Hanson(DHH) 37signals

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Dont Repeat Yourself

Convention Over Configuration

Ruby

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Rails

2005 DHH Hacker 2006 Rails Jolt 2005~2006 Ruby/Rails 1552%

Ruby Tiobe 26 10

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Rails ?Java(Spring/Hibernate) Rails

420 4(5)

3293 1164

1161 113

/ 62/549 55/126

Justin Gehtland Java Rails

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Rails ?

Justin Gehtland Java :Rails = 3.5 : 1 Proc.net PHP : Rails = 10 : 1 JavaEye JAVA : Rails = 10 : 1 thegiive PHP : Rails = 8 : 1

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Rails clone

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Why Ruby?

20% Java 300%

From Beyond Java

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Rails

C

M

V

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DB schema Ruby

class CreatePeople < ActiveRecord::Migration def self.up create_table :people do |t| t.string :name t.integer :age t.date :birthday t.text :bio t.timestamps end end

def self.down drop_table :people endend

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Active RecordORM

class Person < ActiveRecord::Base # end

person = Person.newperson.name "ihower"person.age = 18person.save

person = Person.find(1)puts person.name # ihower

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Action Controller HTTP request

class PeopleController < ApplicationController

# GET /people def index @people = Person.all end end

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method action

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instance variable View

method action

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Action View Ruby HTML

Guestbook :

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MVCModel-View-Control

route.rbHTTP requestGET /users/1

Browser

UsersController

end

def show@user = User.find(params[:id])

respond_to do |format|format.htmlformat.xml

endend

def index......

end

Model

Database

#show.html.erb

User Profile

View

Controller Action

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Thank you.

Programming Ruby (The Pragmatic Programmers)Ruby (OReilly)Get to the Point! (http://johnwlong.com/slides/gettothepoint/)Ruby on Rails slide by thegiive in COSCUP

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Documents

Ruby 程式語言簡介