This document discusses the author's love of Ruby and some of its key qualities, including its simple syntax, object-oriented nature, duck typing, blocks, and open classes. It provides examples of initializing arrays and hashes, defining classes, how everything is an object in Ruby, duck typing without type constraints, using blocks, accepting blocks, and modifying classes in open ways. The author advocates for Ruby but also notes the responsibility that comes with its flexibility.

1. Corey Haines, Journeyman Developer
Ruby
It really is Love
Saturday, May 30, 2009

2. About
Saturday, May 30, 2009

3. Not About
Convincing You To Use Ruby
Saturday, May 30, 2009

4. About
Things I love in Ruby
duck-typing
open classes
(almost) everything is executable ruby code
Saturday, May 30, 2009

5. Should You Learn Ruby?
Saturday, May 30, 2009

6. Corey Haines
Journeyman
Developer
That’s Me!
www.coreyhaines.com
coreyhaines@gmail.com
Saturday, May 30, 2009

7. On To Ruby
Saturday, May 30, 2009

8. “...trying to make Ruby
natural, not simple.”
- Yukihiro Matsumoto
“Matz”
image courtesy Jim Lindley on flickr
Saturday, May 30, 2009

9. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

10. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

11. Initializers
arr = [1, 6, 2, 3, 5]
arr2 = [“Element”, “Another one”]
lookup = { :ruby => “love”,
:c_sharp => “good too”,
:python => “cool” }
Saturday, May 30, 2009

12. Classes
class Rectangle
attr_accessor :width, :height
def initialize(width, height)
self.width = width
self.height = height
end
def area
width * height
end
end
Saturday, May 30, 2009

13. >> r = Rectangle.new(5, 20)
=> #<Rectangle:0x3691d8 @width=5, @height=20>
>> r.area
=> 100
Saturday, May 30, 2009

14. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

15. Everything is an object
>> 9.succ
=> 10
>> 9.nil?
=> false
>> 9.between? 8, 10
=> true
>> 9.class
=> Fixnum
Saturday, May 30, 2009

16. No Really
>> 9.succ
=> 10
>> 9.nil?
=> false
>> 9.between? 8, 10
=> true Wha?
>> 9.class
=> Fixnum
>> Fixnum.class
=> Class
Saturday, May 30, 2009

17. Ever written something like this?
public void MakeItQuack<T>(T quacker)
where T : ICanQuack
{
quacker.Quack();
}
Saturday, May 30, 2009

18. Really Wanted
public void MakeItQuack<T>(T quacker)
where T can quack
{
quacker.quack();
}
Saturday, May 30, 2009

19. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

20. No, not that kind
Saturday, May 30, 2009

21. Duck-Typing
Walks like a duck
Quacks like a duck
Must be a duck?
Saturday, May 30, 2009

22. Well, no
But, we can interact with it like a duck!
And Pretend!
Saturday, May 30, 2009

23. def make_it_quack(quacker)
quacker.quack();
end
Saturday, May 30, 2009

24. Type != Class
Behavior/Interaction-Orientation
Saturday, May 30, 2009

25. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

26. Blocks
a = [5, 7, 10, 24]
a.each do |num|
puts num
end
b = a.map do |num|
num * 2
end
puts b.inspect
Saturday, May 30, 2009

27. Accepting Blocks
def five_times
yield 1
yield 2
yield 3
yield 4
yield 5
end
five_times do |num|
puts num
end
Saturday, May 30, 2009

28. Accepting Blocks
def five_times(&block)
block.call(1)
block.call(2)
block.call(3)
block.call(4)
block.call(5)
end
five_times do |num|
puts num
end
Saturday, May 30, 2009

29. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

30. Open Classes
Say goodbye to sealed/virtual/override/argh
Saturday, May 30, 2009

31. def convert(to_convert)
return nil if to_convert.nil?
return to_convert if to_convert.empty?
do_conversion(to_convert)
end
Saturday, May 30, 2009

32. As You Wish
class NilClass
def empty?
true
end
end
Saturday, May 30, 2009

33. def convert(to_convert)
return to_convert if to_convert.empty?
do_conversion(to_convert)
end
Saturday, May 30, 2009

34. Setting Time
current_time = 17
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35. write the code you wish you had
current_time = 5.pm
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36. Then get it working
class Fixnum
def pm
self + 12
end
end
Saturday, May 30, 2009

37. Type != Class (redux)
a = “coreyhaines@gmail.com;me@coreyhaines.com”
Saturday, May 30, 2009

38. Type != Class (redux redux)
a = “coreyhaines@gmail.com;me@coreyhaines.com”
a.extend(EmailAddressList)
puts a.email_addresses.inspect
a.each_address do |address|
Mailer.send_email_to(address)
end
Saturday, May 30, 2009

39. Remember
With great power comes great responsibility
Saturday, May 30, 2009

40. Qualities
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

41. Qualities
Awesomeness!
Simple Syntax
Object-Oriented
Duck-Typing
Blocks
Open Classes
Saturday, May 30, 2009

42. Method Missing
Saturday, May 30, 2009

43. Examples
Builder
Saturday, May 30, 2009

44. Mixins
Saturday, May 30, 2009

45. Type != Class
Saturday, May 30, 2009

46. Examples
Email Addresses
Saturday, May 30, 2009

47. defining methods
Saturday, May 30, 2009

48. Examples
Email Addresses
Saturday, May 30, 2009