Why Ruby?

{Why Ruby?

my story how I started learning and using Ruby

Plan1. About me2. Why Ruby?3. What is Ruby?4. Ruby on Rails5. Ruby-world Ecosystem6. Future7. Questions

About me

Igor Kasyanchuk

Education: National University of Oil and Gas, PZ-01-1Worked at: Eleks, SoftServe, freelancing, own projectsCompleted projects: 20+Used: Java, Visual C++, C++ BuilderUsing: Ruby, Ruby on Rails, HTML/CSS/JS/etcWorking now: in SoftServe as Ruby, Ruby on Rails Team/Tech Lead

Why Ruby?

I was tired of …

... and many other things

Why Ruby?

And I met Ruby …

say = "I love Ruby"puts say

say['love'] = "*love*"puts say.upcase

5.times { puts say }

What is Ruby?

Ruby is a dynamic, reflective, object-oriented, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.

… from Wikipedia

Q: What other dynamic languages do you know?

What is Ruby?

Ruby is a dynamic, reflective, object-oriented, general-purpose programming language. It was designed and developed in the mid-1990s by Yukihiro "Matz" Matsumoto in Japan.

… from Wikipedia

What other dynamic languages do you know? – PHP, Python, Node.JS

Ruby is• Dynamic programming language• Less is more, efficient code, easy to read, elegant• One of the best language for creating startups (Twitter,

Groupon, Airbnb, Slideshare)• Companies using it: HP, Twitter, Intel, NASA, HULU, Groupon,

Airbnb, Github, Slideshare• Has ~90K libraries, which were downloaded ~3.8M times• Killer app: Ruby on Rails

Also, Ruby ishttp://hyperpolyglot.org/scripting

PHP

$a = [1, 2, 3]min($a)max($a)

Python

min([1, 2, 3])max([1, 2, 3])

Ruby

[1, 2, 3].min[1, 2, 3].max

Java

import java.util.Arrays;import java.util.Collections;

import org.apache.commons.lang.ArrayUtils;

public class MinMaxValue {

public static void main(String[] args) { char[] a = {'3', '5', '1', '4', '2'};

List b = Arrays.asList(ArrayUtils.toObject(a));

System.out.println(Collections.min(b)); System.out.println(Collections.max(b)); }}

Syntax1. Overview2. Loops3. Blocks4. Classes, Mixins5. OOP in Ruby6. “Dynamicity”

Overviewputs "Hello World"

"LOREM".downcase

"lorem".length

"abcd".split("")if /1999/.match(s) puts "party!"end

t = Time.now

Time.now.strftime("%Y-%m-%d %H:%M:%S")

a = [1, 2, 3, 4]

a[-1](1..1_000_000).each do |i| …end

role = :admin

ROLES = [‘admin’, ‘user’]

x = 1000

user = user.new unless user

Loopsi=0while i < 3 print i, " while\n” i += 1end

for ss in 0..2 print ss, " for doubledot\n”end

array=['zero', 'one', 'two', 'three', 'four', 'five']array.each{|ss| print ss, " array.each\n"}

array[0,3].each{|ss| print ss, " array_first_three.each\n”}

Blocksdef simple puts 'Here comes the code block!’ yield puts 'There was the code block!’end

Now:simple { puts 'Hooray! The code block is here!' }

Result:Here comes the code block!Hooray! The code block is here!There was the code block!

Classes, Mixinsclass Greeter def initialize(name) @name = name.capitalize end

def salute puts "Hello #{@name}!" endend

# Create a new objectg = Greeter.new("world")

# Output "Hello World!"g.salute

# Creating mixinmodule Log def log(message) puts message endend

# Creating classclass User include Logend

user = User.newuser.log “hello user”

OOP in Ruby

1. Everything is an object (numbers, strings, classes, everything…)2. Class can inherit only from one parent (single inheritance)3. You can use mixins (in other languages eq. to interfaces + implementation)

5.times do |e| puts “hello world”end

[1,0,6,9,3,5].select{|e| e > 3}.collect{|e| e*2}.min.times do |e| puts eend

“Dynamicity”class Greeter def initialize(name) @name = name end

def method_missing(e) greeting = e.to_s.capitalize "#{greeting} #{@name}" endend

g = Greeter.new("Igor")puts g.hello

=> Hello Igor

1. Strong reflection2. eval3. method_missing4. send5. overload, override anything6. modify, remove, add methods on the fly

Ruby on RailsRuby on Rails, or simply Rails, is an open source web application framework written in Ruby. Rails is a full-stack framework that emphasizes the use of well-known software engineering patterns and paradigms, including convention over configuration (CoC), don't repeat yourself (DRY), the active record pattern, and model–view–controller (MVC).

… Wikipedia

Author:David Heinemeier Hansson

Since 2004

From Denmark

Ruby on Rails1. Built on Ruby2. Web Application Framework3. Blog in 15 minutes4. MVC, CoC, DRY

Built on Ruby

To work with Ruby on Rails you just need to install Ruby our your computer and then install ”rails” as gem.

gem install rails

Web Application Framework

• HTML/HAML/SLIM…• CSS/SCSS/SASS…• JS/CoffeeScript….• MySQL/Postgres/Mongo….• REST/API• Testing• Java, C, Resque, Sphinx, ElasticSearch, etc

Blog in 15 minutes

Check it!

Blog in 15 minutes

Check it!

MVC• Object Relation Mapping• Database Agnostic• CRUD simple• Class to Table, Row to Object

class User < ActiveRecord::Base has_many :photosend

User.first => SELECT `users`.* FROM `users` ORDER BY `users`.`id` ASC LIMIT 1

User.find(2) => SELECT `users`.* FROM `users` WHERE `users`.`id` = 2 LIMIT 1

User.find_by(first_name: "igor") =>SELECT `users`.* FROM `users` WHERE `users`.`first_name` = 'igor' LIMIT 1

user = User.find(1)user.photos => SELECT photos.* from photos where user_id = 1

MVCConnecting view and model

сlass UsersController < ApplicationController def index @users= User.all end

end

MVCGenerating HTML (using SLIM)

table - @users.each do |user| tr td= user.first_name td= user.last_name

CoCConvention over Configuration

DRY # def easy_ui # self.easy.presence || 'EASY' # end

# def medium_ui # self.medium.presence || 'MEDIUM' # end

# def hard_ui # self.hard.presence || 'HARD' # end

[:easy, :medium, :hard].each do |field| define_method "#{field}_ui" do [field].presence || field.to_s.upcase end end

Ruby-world EcosystemInterpreters: MRI, jRuby, Rubinius, …Frameworks: Ruby on Rails, Sinatra, E, … Editors: Sublime, RubyMine, VIM, …Tests: Rspec, Selenium, Capybara, minitestServers: Passenger, Unicorn, Puma, Thin, …Libraries (gems): for any tasks … xml, video, image, data processing, API, ….Mobile App: RubyMotion – create native iOS apps in RubyCommunity: Google groups, stackoverflow, rubyclub.com.ua, …

And more …. Github, BitBucket, CoffeeScript, SASS/SCSS, HAML/SLIM,OAuth, Emails, Ajax, Books(30+), integration with Backbone (and other JS frameworks), payments (PrivatBank has gem), …

Future• Ruby 2.2 is coming• Rails 4.2 is coming + Rails 5 branch is created• Many job offers• New Projects, challenges, startups

Questions?

skype: igorkasyanchuk

feel free to contact me

Thank you

and welcome to Ruby world