A brief and basic introduction to the syntax of Ruby 1.8, along with a few nice language features. This is a talk I gave at one of our first Rochester on Rails meetings.

1. Ruby Programmers’ Best Friend Jason Morrison January 19, 2006 Rochester on Rails

2. History

3. Ruby Yukihiro “Matz” Matsumoto February 24, 1993

4. Perl Java Python Ruby PHP 1987 1991 1993 1995

5. Examples!

6. 5.times { print “Ruby! " }

7. Ruby! Ruby! Ruby! Ruby! Ruby! 5.times { print “Ruby! " }

8. [‘one’,‘two’,‘three’].each {|num| puts num.capitalize }

9. [‘one’,‘two’,‘three’].each {|num| puts num.capitalize } One Two Three

10. Everything is an object

11. -21474836480.abs

12. -21474836480.abs 21474836480

13. “ Rats live on no evil star”  .reverse.capitalize

14. “ Rats live on no evil star”  .reverse.capitalize “ Rats live on no evil star”

15. 3.hours.from_now

16. 3.hours.from_now Thu Jan 19 22:05:00 Eastern  Standard Time 2006

17. Conventions

18. Variables colored_index_cards

19. Class Names DromedaryDiner

20. Symbols :creme_de_menthe

21. Instance Variables @euros_per_liter

22. Constants Kilograms_Per_Pound

23. Syntax

24. Methods def say_hello(name) result = “Hello, #{name}!” return result end puts say_hello(“world”)

25. Methods def say_hello(name) “Hello, #{name}!” end puts say_hello(“world”)

26. Classes class MathWhiz def say_square(value) puts value * value end end sam = MathWhiz.new sam.say_square(5)

27. Open Classes class Integer def squared self * self end end 5.squared #=> 25

28. Inheritance class Whopper < Burger @maker = “Burger King” @calories = 0.67 * 10**3 end

29. Class Methods class FileUtil def self.mkdir(dir) # do it! end end FileUtil.mkdir(“oranges”)

30. Modules module Trig PI = 3.141592654 def Trig.sin(x) # .. end def Trig.cos(x) # .. end end

31. Modules require &quot;trig&quot; y = Trig.sin(Trig::PI/4) 0.707106780551956

32. Mixins module Debug def whoAmI? “ #{self.type.name} ” + “ (#{self.id}): ” + “ #{self.to_s}&quot; end end

33. Mixins class Phonograph include Debug # ... end ph = Phonograph.new(&quot;West End Blues&quot;) ph.whoAmI? &quot;Phonograph (#537766170): West End Blues&quot;

34. Attributes class PlainOldRubyObject attr_accessor :food, :drinks attr_reader :advice attr_writer :write_only end

35. Scope class Poet #public by default def poetry end protected def family_legacy end private def hopes_and_dreams end end

36. Arrays

37. foo = [] foo << 1 #=> [1] foo << 2 #=> [1, 2] foo << 3 #=> [1, 2, 3]

38. bar = [1, 2, 3] bar << 4 #=> [1, 2, 3, 4] bar << 5 #=> [1, 2, 3, 4, 5] bar << 6 #=> [1, 2, 3, 4, 5, 6]

39. folks = %w( Charles Ed Amanda ) #=> [“Charles”, “Ed”, “Amanda”] folks[1] Ed

40. Hashes

41. menu = { :douglas_sirk_steak => 17.50, :vanilla_coke => 2.75, :durwood_kirby_burger => 9.75, :five_dollar_shake => 5.00 } menu[:vanilla_coke] 2.75

42. Flow

43. if ( score >= 5000 ) puts “You win!” elsif ( score <= 0 ) puts “Game over.” else puts “Current score: #{score}” end

44. puts “Watch out!” if lion_distance < 5

45. Blocks

46. 1.upto(5) { |x| puts x } 1 2 3 4 5

47. 5.downto(1) do |time| print “#{time}... ” puts “!” if time <= 3 end 5... 4... 3... ! 2... ! 1... !

48. Fín!

49. Homepage www.ruby-lang.org Try Ruby in your browser tryruby.hobix.com Ruby with humor  www.poignantguide.net