An introduction to the Ruby language and RSpec

1. THE RUBY LANGUAGE

2. THE RUBY LANGUAGE
• Originally by Yukihiro "Matz" Matsumoto
• “Ruby is designed for programmer productivity and fun, following
the principles of good user interface design. He stresses that
systems design needs to emphasize human, rather than computer,
needs.”
http://en.wikipedia.org/wiki/Ruby_(programming_language)#History
• Ruby 1.0 was released in 1996.

3. RUBY LANGUAGE OVERVIEW
• Dynamically typed
• Interpreted
• Can be modified at runtime
• Object oriented
• Blocks & lambdas
• Nice support for Regular Expressions

4. RUBY VERSIONS
ruby -v
•1.8.6 – Still around but mostly supplanted by 1.8.7
•1.8.7 – some 1.9 features, compatible w/ 1.8.6
•1.9.2 – latest version, many VMs, Rails 2.3+

5. RUBY VMS
• MRI (Matz's Ruby Interpreter) the original Ruby, default for 1.8
• YARV (yet another Ruby VM) faster than MRI, default for 1.9
• JRuby (Java)
• Rubinius (pure ruby)
• IronRuby (.NET)
• MacRuby, HotCocoa
• HotRuby/RubyJS (Flash/Javascript)

6. LETS GET STARTED
• IRB: InteractiveRuBy
>> 4
>> 4 + 4

7. EVERYTHING IS AN OBJECT
“test”.upcase
“test”.class
“test”.methods

8. EVERYTHING EVALUATES TO
SOMETHING
2+2
(2+2).zero?

9. METHODS ARE MESSAGES
thing.do(4)
thing.do 4
thing.send “do”, 4

10. OPERATORS ARE METHODS
thing.do 4 3+2
thing.do(4) 3.+(2)
thing.send “do”, 4 3.send "+", 2

11. DEFINING CLASSES
• Let’s write some code!

12. INTRODUCTION TO RSPEC
• Describe the feature
• Verify expectation

13. RSPEC SYNTAX
describe Something do
end

14. RSPEC SYNTAX
describe Something do
it "should do whatever it should do"
end

15. RSPEC SYNTAX
describe Something do
it "should do whatever it should do" do
end
end

16. RSPEC SYNTAX
describe Something do
it "should do whatever it should do" do
s = Something.new
end
end

17. RSPEC SYNTAX
describe Something do
it "should do whatever it should do" do
s = Something.new
s.do_whatever(3, 2, 1)
end
end

18. RSPEC SYNTAX
describe Something do
it "should do whatever it should do" do
s = Something.new
s.do_whatever(3, 2, 1).should == "blast off!"
end
end

19. RSPEC SYNTAX
describe Something do
it "should do whatever it should do" do
s = Something.new
s.do_whatever(3, 2, 1).should == "blast off!"
end
end

20. • Let's try it!