Basic introduction to the history and uses of the Ruby programming lanaguage. http://github.com/jwthompson2/barcamp-nola-2009/

1. INTRODUCING RUBY

2. WHO IS THIS GUY?
James Thompson
@plainprogrammer
james@plainprograms.com
Web Administrator & Student
@ New Orleans Baptist
Theological Seminary

3. WHAT IS RUBY?
Ruby is a dynamic, open source programming language
with a focus on simplicity and productivity – ruby-lang.org

4. HISTORY
Created by Yukihiro “matz” Matsumoto
Started development in 1993
First public release in 1995 (Japan)
First English release in 1998
“make Ruby natural, not simple.”

5. CURRENT STATE
Legacy Stable: 1.8.7p72
Current Stable: 1.9.1p129
A community in transition
Alternatives to MRI

6. INSTALLING RUBY
•Windows: Cygwin is the best option. One-click installer
available but out of date.
•Linux: apt-get install ruby rdoc irb
•OS X: Already installed in 10.5. Available through
MacPorts as well.

7. LEARNING RUBY

8. RUBY’S COMMANDS
•ruby main interpreter
•irb interactive ruby shell
•ri ruby information, manpages for classes
•rdoc ruby documentation compiler
•erb ruby templating system

9. RUBY CONVENTIONS
•variable_name
•method_name
•ClassName
•ModuleName
•ConstantName | CONTSTANT_NAME

10. RUBY SYNTAX

11. OBJECT
ORIENTATION
5.class #=> Fixnum
In ruby everything is an object. 3.9.class #=> Float
"Hello".class #=> String
Fixnum.class #=> Class
This is both powerful and
nil.class #=> NilClass
different.

12. SYMBOLS
:a_symbol
opts = {
:a_key => "Some value!",
:another_key => "another value..."
}

13. INSTANCE & CLASS VARIABLES
@instance_variable
@@class_variable

14. STRINGS
name = 'BarCamp Joe'
greeting = "Hello, #{name}!"
long_greeting <<-EOS
Hello my old friend, #{name}!
How have you been?
EOS
alternate_greeting = %{G'day, #{name.upcase}!}

15. NUMBERS
a = 1
b = 2.0
c = 2.3e5
d = 0x3F
e = 0244

16. METHODS
def say_hello(name)
result = "Hello, #{name}!"
end
puts say_hello("BarCamp NOLA")

17. METHODS
def say_hello(name)
result = "Hello, #{name}"
return result
end
puts say_hello("BarCamp NOLA")

18. CLASSES
class Greeter
def say_hello(name)
puts "Hello, #{name}!"
end
end
doorman = Greeter.new
doorman.say_hello("BarCampers")

19. CLASSES
class RudeGreeter < Greeter
def say_hello(name)
puts ""
end
end

20. CLASSES
class Greeter
def initialize(name)
@greeters_name = name
end
end

21. CLASSES
class Greeter
attr_reader :name
end
doorman.name

22. CLASSES
class RudeGreeter < Greeter
def initialize(name, rudeness)
@rudeness = rudeness
super(name)
end
end

23. MODULES
module Farewell
def bid_farewell(name)
"Good bye, #{name}!"
end
end

24. MODULES
class Greeter
include Farewell
end
doorman = Greeter.new("John")
doorman.bid_farewell("BarCampers")

25. CLASS/MODULE MUTABILITY
class Numeric
def plus(n)
self.+(n)
end
end
y = 5.plus 6 #=> 11

26. CONTROL STRUCTURES
if "a" == "a"
puts "a"
end
unless "a".nil?
puts "a"
end
puts "a" unless "a".nil?
name = case
when num == 1: "one"
when num == 2: "two"
else
num.to_s
end
[1,2,3].each do |value|
puts value.to_s
end

27. TYPES
•Numbers
•Strings
•Regular Expressions (/^(foo|bar)+$/)
•Arrays ([1,2,3])
•Hashes
•Ranges (1..10, "a"..."z")
•Symbols

28. BLOCKS, PROCS & LAMBDAS
[1,2,3].each do |value|
puts value.to_s
end
square = Proc.new do |n|
n ** 2
end

29. RUBYGEMS

30. CPAN Pear PECL RAA Rubyforge Github PyPI
17,000
12,750
8,500
4,250
Obsolete
0
Perl Ruby Python PHP
PERL, PHP & RUBY PACKAGES

31. SEEING WHAT’S OUT THERE
gem list --remote
gem list

32. GETTING HELP
gem help
gem help commands

33. INSTALLING GEMS
gem install rails
gem install mysql sqlite3-ruby
gem install rails --no-ri --no-rdoc

34. COMMANDS FOR GEMS
rails --version

35. REMOVING GEMS
gem uninstall mysql

36. WHY USE RUBY?

37. QUESTIONS?

38. MORE RESOURCES
ruby-lang.org
ruby-doc.org
rubygems.org
rubyforge.org
pragprog.com