case.rb

class Cocktail
  attr_accessor :name
  def initialize(name)
    @name = name
  end
  
  def liquor
    case self.name
    when "journalist": "gin"
    when "sazerac": "whiskey"
    when "mojito": "rum"
    end
  end
end

cocktail = Cocktail.new("sazerac")
puts cocktail.liquor

# 1.8.7 > whiskey
# 1.9.3 > syntax error, unexpected ':', expecting keyword_then or ',' or ';' or '\n'

dates.rb

require 'rubygems'
require 'date'

Date.parse("10/13/2012").to_s
# 1.8.7 > "2012-10-13"
# 1.9.3 > ArgumentError: invalid date

Date.parse("10/11/2012").to_s
# 1.8.7 > "2012-10-11"
# 1.9.3 > "2012-11-10"

encoding.rb

# encoding: utf-8

member.rb

puts ('a'..'z').member?("airbnb")
# 1.8.7 > true
# 1.9.3 > false

methods.rb

String.methods.include?("freeze")
# 1.8.7 > true
# 1.9.3 > false

methods2.rb

String.respond_to?(:freeze)
# 1.8.7 > true
# 1.9.3 > true

punct.rb

# encoding: UTF-8

PUNCTUATION_CHARS = '!"#$%&\'()*+,-./:;<=>?@\[\]^_\`{|}~'
puts PUNCTUATION_CHARS.gsub(/[[:punct:]]/, "☃")

# 1.8.7 > ☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃☃
# 1.9.3 > ☃☃☃$☃☃☃☃☃☃+☃☃☃☃☃☃<=>☃☃☃☃☃☃^☃☃`☃|☃~

regex.rb

# encoding: UTF-8

puts "1: " + "Hello Chloë,".gsub(/[\w]*,/u, '')
puts "2: " + "Hello Chloë,".gsub(/[[:alnum:]]*,/u, '')
puts "3: " + "Hello Chloë,".gsub(/[\w[:alnum:]]*,/u, '')

# ruby 1.8.7 output:
# 1: Hello 
# 2: Hello Chloë
# 3: Hello 

# ruby 1.9.3 output:
# 1: Hello Chloë
# 2: Hello 
# 3: Hello 

select.rb

h = {1 => "a", 2 => "b", 3 => "c"}

puts h.select{|x,y| true}.inspect
puts Hash[h.select{|x,y| true}].inspect

# 1.8.7 output:
# [[1, "a"], [2, "b"], [3, "c"]]
# {1=>"a", 2=>"b", 3=>"c"}

# 1.9.3 output:
# {1=>"a", 2=>"b", 3=>"c"}
# {1=>"a", 2=>"b", 3=>"c"}

simple_hash.rb

h = {"foo", "bar"}
puts h.inspect

# 1.8.7 > {"foo"=>"bar"}
# 1.9.3 > syntax error, unexpected ',', expecting tASSOC