Comparison of Scala and Ruby languages and between Rails and Play frameworks.

1. – Martin Mazur: http://youtu.be/FPBVxpl8NMo @ DevDay
“Why you should talk to
strangers?”

2. Ruby vs Scala
• Designed for humans, not machines
• Extreme flexibility: if you mess up, it’s on you
• Everything has to be easy, elegant and fun
• DSL on top of DSLs on top of DSLs
• Testing is critical
• Things move quickly, learn to keep up
• Passionate and vibrant community
• Have the best of both object oriented and functional
programming worlds
• Let the compiler do some of the work for you
• Concurrency matters
• Less ceremony than Java, but aiming for same or better
performance
• Live in harmony with the Java ecosystem

3. Installation
brew install ruby
brew curl -sSL https://get.rvm.io | bash -s stable ruby
or
brew install scala
or
curl -O http://downloads.typesafe.com/scala/2.11.7/scala-2.11.7.tgz
| tar -xvf -

4. Packages
addSbtPlugin("com.typesafe.play" % "sbt-plugin" % "2.2.7")
build.sbt (obligate versioning)
sbt compile
gem 'rails', '~> 5.0.0'
Gemfile (optional versioning)
+ Gemfile.lock (locked versions)
bundle

6. filter_and_reduce

7. named_arguments

8. partial_functions

9. pattern_matching

10. random_from_array

11. monkey_patching

12. mixins

13. Rails vs Play!

14. Boilerplate
rails new example
play new example

15. Routing
get '/clients/all', to: 'clients#index'
get '/clients/:id', to: 'clients#show'
root 'application#home'
GET /clients/all controllers.Clients.index()
GET /clients/:id controllers.Clients.show(id: Long)
GET / controllers.Application.home()

16. Templates
<ul>
@(3 times) {
<li>list item</li>
}
</ul>
// Scala Template Engine
<ul>
<% 3.times do %>
<li>list item</li>
<% end %>
</ul>
# Embedded Ruby

17. Unit Tests
test 'my test' do
array = [1, 2, 3]
assert_equal 1, array.first
end
@Test def myTest {
val array = List(1, 2, 3)
assert(array(0) === 1)
}

18. Specs
describe 'HelloWorld spec' do
context "The 'Hello world' string should" do
it 'contain 11 characters' do
'Hello world'.size.should be 11
end
it "end with 'world'" do
'Hello world'.should end_with('world')
end
end
end
class HelloWorldSpec extends Specification {
"The 'Hello world' string" should {
"contain 11 characters" in {
'Hello world' must have size(11)
}
"end with 'world'" in {
'Hello world'.should end_with('world')
}
}
}

19. JSON rendering
def index
render json: { message: 'Hello world' }
end
def index = Json("{message: 'Hello world'}")

20. Documentation

21. Coursera
Twitter
LinkedIn
Guardian
Foursquare
Apache Spark
Rails
Vagrant
Homebrew
RSpec
Chef
Puppet
Basecamp
Slideshare
GitHub
Freckle
Shopify
Imgur
Heroku
Flag products

22. Resources:
https://github.com/KamilLelonek/scala-vs-ruby
https://blog.lelonek.me/