Merge branch 'master' of git://github.com/lifo/docrails

Conflicts:
	activerecord/RUNNING_UNIT_TESTS

1 files changed, 312 insertions, 311 deletions

diff --git a/railties/guides/source/initialization.textile b/railties/guides/source/initialization.textile
index 638830cd83..1d5b0c0c11 100644
--- a/railties/guides/source/initialization.textile
+++ b/railties/guides/source/initialization.textile
@@ -20,15 +20,15 @@ h4. +bin/rails+
 The actual +rails+ command is kept in _bin/rails_ at the and goes like this:
 
 <ruby>
-  #!/usr/bin/env ruby
-
-  begin
-    require "rails/cli"
-  rescue LoadError
-    railties_path = File.expand_path('../../railties/lib', __FILE__)
-    $:.unshift(railties_path)
-    require "rails/cli"
-  end
+#!/usr/bin/env ruby
+
+begin
+  require "rails/cli"
+rescue LoadError
+  railties_path = File.expand_path('../../railties/lib', __FILE__)
+  $:.unshift(railties_path)
+  require "rails/cli"
+end
 </ruby>
 
 This file will attempt to load +rails/cli+ and if it cannot find it then add the +railties/lib+ path to the load path (+$:+) and will then try to require it again.
@@ -38,22 +38,22 @@ h4. +railites/lib/rails/cli.rb+
 This file looks like this:
 
 <ruby>
-  require 'rbconfig'
-  require 'rails/script_rails_loader'
+require 'rbconfig'
+require 'rails/script_rails_loader'
 
-  # If we are inside a Rails application this method performs an exec and thus
-  # the rest of this script is not run.
-  Rails::ScriptRailsLoader.exec_script_rails!
+# If we are inside a Rails application this method performs an exec and thus
+# the rest of this script is not run.
+Rails::ScriptRailsLoader.exec_script_rails!
 
-  require 'rails/ruby_version_check'
-  Signal.trap("INT") { puts; exit }
+require 'rails/ruby_version_check'
+Signal.trap("INT") { puts; exit }
 
-  if ARGV.first == 'plugin'
-    ARGV.shift
-    require 'rails/commands/plugin_new'
-  else
-    require 'rails/commands/application'
-  end
+if ARGV.first == 'plugin'
+  ARGV.shift
+  require 'rails/commands/plugin_new'
+else
+  require 'rails/commands/application'
+end
 </ruby>
 
 The +rbconfig+ file here is out of Ruby's standard library and provides us with the +RbConfig+ class which contains useful information dependent on how Ruby was compiled. We'll see this in use in +railties/lib/rails/script_rails_loader+.
@@ -76,46 +76,46 @@ The +rails/script_rails_loader+ file uses +RbConfig::Config+ to gather up the +b
 Back in +rails/cli+, the next line is this:
 
 <ruby>
-  Rails::ScriptRailsLoader.exec_script_rails!
+Rails::ScriptRailsLoader.exec_script_rails!
 </ruby>
 
 This method is defined in +rails/script_rails_loader+ like this:
 
 <ruby>
-  def self.exec_script_rails!
-    cwd = Dir.pwd
-    return unless in_rails_application? || in_rails_application_subdirectory?
-    exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application?
-    Dir.chdir("..") do
-      # Recurse in a chdir block: if the search fails we want to be sure
-      # the application is generated in the original working directory.
-      exec_script_rails! unless cwd == Dir.pwd
-    end
-  rescue SystemCallError
-    # could not chdir, no problem just return
+def self.exec_script_rails!
+  cwd = Dir.pwd
+  return unless in_rails_application? || in_rails_application_subdirectory?
+  exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application?
+  Dir.chdir("..") do
+    # Recurse in a chdir block: if the search fails we want to be sure
+    # the application is generated in the original working directory.
+    exec_script_rails! unless cwd == Dir.pwd
   end
+rescue SystemCallError
+  # could not chdir, no problem just return
+end
 </ruby>
 
 This method will first check if the current working directory (+cwd+) is a Rails application or is a subdirectory of one. The way to determine this is defined in the +in_rails_application?+ method like this:
 
 <ruby>
-  def self.in_rails_application?
-    File.exists?(SCRIPT_RAILS)
-  end
+def self.in_rails_application?
+  File.exists?(SCRIPT_RAILS)
+end
 </ruby>
 
 The +SCRIPT_RAILS+ constant defined earlier is used here, with +File.exists?+ checking for its presence in the current directory. If this method returns +false+, then +in_rails_application_subdirectory?+ will be used:
 
 <ruby>
-  def self.in_rails_application_subdirectory?(path = Pathname.new(Dir.pwd))
-    File.exists?(File.join(path, SCRIPT_RAILS)) || !path.root? && in_rails_application_subdirectory?(path.parent)
-  end
+def self.in_rails_application_subdirectory?(path = Pathname.new(Dir.pwd))
+  File.exists?(File.join(path, SCRIPT_RAILS)) || !path.root? && in_rails_application_subdirectory?(path.parent)
+end
 </ruby>
 
 This climbs the directory tree until it reaches a path which contains a +script/rails+ file. If a directory is reached which contains this file then this line will run:
 
 <ruby>
-  exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application?
+exec RUBY, SCRIPT_RAILS, *ARGV if in_rails_application?
 </ruby>
 
 This is effectively the same as doing +ruby script/rails [arguments]+. Where +[arguments]+ at this point in time is simply "server".
@@ -125,9 +125,9 @@ h4. +script/rails+
 This file looks like this:
 
 <ruby>
-  APP_PATH = File.expand_path('../../config/application',  __FILE__)
-  require File.expand_path('../../config/boot',  __FILE__)
-  require 'rails/commands'
+APP_PATH = File.expand_path('../../config/application',  __FILE__)
+require File.expand_path('../../config/boot',  __FILE__)
+require 'rails/commands'
 </ruby>
 
 The +APP_PATH+ constant here will be used later in +rails/commands+. The +config/boot+ file that +script/rails+ references is the +config/boot.rb+ file in our application which is responsible for loading Bundler and setting it up.
@@ -137,19 +137,19 @@ h4. +config/boot.rb+
 +config/boot.rb+ contains this:
 
 <ruby>
-  require 'rubygems'
+require 'rubygems'
 
-  # Set up gems listed in the Gemfile.
-  gemfile = File.expand_path('../../Gemfile', __FILE__)
-  begin
-    ENV['BUNDLE_GEMFILE'] = gemfile
-    require 'bundler'
-    Bundler.setup
-  rescue Bundler::GemNotFound => e
-    STDERR.puts e.message
-    STDERR.puts "Try running `bundle install`."
-    exit!
-  end if File.exist?(gemfile)
+# Set up gems listed in the Gemfile.
+gemfile = File.expand_path('../../Gemfile', __FILE__)
+begin
+  ENV['BUNDLE_GEMFILE'] = gemfile
+  require 'bundler'
+  Bundler.setup
+rescue Bundler::GemNotFound => e
+  STDERR.puts e.message
+  STDERR.puts "Try running `bundle install`."
+  exit!
+end if File.exist?(gemfile)
 </ruby>
 
 In a standard Rails application, there's a +Gemfile+ which declares all dependencies of the application. +config/boot.rb+ sets +ENV["BUNDLE_GEMFILE"]+ to the location of this file, then requires Bundler and calls +Bundler.setup+ which adds the dependencies of the application (including all the Rails parts) to the load path, making them available for the application to load. The gems that a Rails 3.1 application depends on are as follows:
@@ -186,34 +186,34 @@ h4. +rails/commands.rb+
 Once +config/boot.rb+ has finished, the next file that is required is +rails/commands+ which will execute a command based on the arguments passed in. In this case, the +ARGV+ array simply contains +server+ which is extracted into the +command+ variable using these lines:
 
 <ruby>
-  aliases = {
-    "g"  => "generate",
-    "c"  => "console",
-    "s"  => "server",
-    "db" => "dbconsole"
-  }
+aliases = {
+  "g"  => "generate",
+  "c"  => "console",
+  "s"  => "server",
+  "db" => "dbconsole"
+}
 
-  command = ARGV.shift
-  command = aliases[command] || command
+command = ARGV.shift
+command = aliases[command] || command
 </ruby>
 
 If we used <tt>s</tt> rather than +server+, Rails will use the +aliases+ defined in the file and match them to their respective commands. With the +server+ command, Rails will run this code:
 
 <ruby>
-  when 'server'
-    # Change to the application's path if there is no config.ru file in current dir.
-    # This allows us to run script/rails server from other directories, but still get
-    # the main config.ru and properly set the tmp directory.
-    Dir.chdir(File.expand_path('../../', APP_PATH)) unless File.exists?(File.expand_path("config.ru"))
-
-    require 'rails/commands/server'
-    Rails::Server.new.tap { |server|
-      # We need to require application after the server sets environment,
-      # otherwise the --environment option given to the server won't propagate.
-      require APP_PATH
-      Dir.chdir(Rails.application.root)
-      server.start
-    }
+when 'server'
+  # Change to the application's path if there is no config.ru file in current dir.
+  # This allows us to run script/rails server from other directories, but still get
+  # the main config.ru and properly set the tmp directory.
+  Dir.chdir(File.expand_path('../../', APP_PATH)) unless File.exists?(File.expand_path("config.ru"))
+
+  require 'rails/commands/server'
+  Rails::Server.new.tap { |server|
+    # We need to require application after the server sets environment,
+    # otherwise the --environment option given to the server won't propagate.
+    require APP_PATH
+    Dir.chdir(Rails.application.root)
+    server.start
+  }
 </ruby>
 
 This file will change into the root of the directory (a path two directories back from +APP_PATH+ which points at +config/application.rb+), but only if the +config.ru+ file isn't found. This then requires +rails/commands/server+ which requires +action_dispatch+ and sets up the +Rails::Server+ class.
@@ -239,7 +239,7 @@ The +methods.rb+ file is responsible for defining methods such as +camelize+, +u
 In this file there are a lot of lines such as this inside the +ActiveSupport+ module:
 
 <ruby>
-  autoload :Inflector
+autoload :Inflector
 </ruby>
 
 Due to the overriding of the +autoload+ method, Ruby will know to look for this file at +activesupport/lib/active_support/inflector.rb+ when the +Inflector+ class is first referenced.
@@ -263,10 +263,10 @@ h4. +rails/commands/server.rb+
 The +Rails::Server+ class is defined in this file as inheriting from +Rack::Server+. When +Rails::Server.new+ is called, this calls the +initialize+ method in +rails/commands/server.rb+:
 
 <ruby>
-  def initialize(*)
-    super
-    set_environment
-  end
+def initialize(*)
+  super
+  set_environment
+end
 </ruby>
 
 Firstly, +super+ is called which calls the +initialize+ method on +Rack::Server+.
@@ -278,10 +278,10 @@ h4. Rack: +lib/rack/server.rb+
 The +initialize+ method in +Rack::Server+ simply sets a couple of variables:
 
 <ruby>
-  def initialize(options = nil)
-    @options = options
-    @app = options[:app] if options && options[:app]
-  end
+def initialize(options = nil)
+  @options = options
+  @app = options[:app] if options && options[:app]
+end
 </ruby>
 
 In this case, +options+ will be +nil+ so nothing happens in this method.
@@ -289,64 +289,64 @@ In this case, +options+ will be +nil+ so nothing happens in this method.
 After +super+ has finished in +Rack::Server+, we jump back to +rails/commands/server.rb+. At this point, +set_environment+ is called within the context of the +Rails::Server+ object and this method doesn't appear to do much at first glance:
 
 <ruby>
-  def set_environment
-    ENV["RAILS_ENV"] ||= options[:environment]
-  end
+def set_environment
+  ENV["RAILS_ENV"] ||= options[:environment]
+end
 </ruby>
 
 In fact, the +options+ method here does quite a lot. This method is defined in +Rack::Server+ like this:
 
 <ruby>
-  def options
-    @options ||= parse_options(ARGV)
-  end
+def options
+  @options ||= parse_options(ARGV)
+end
 </ruby>
 
 Then +parse_options+ is defined like this:
 
 <ruby>
-  def parse_options(args)
-    options = default_options
+def parse_options(args)
+  options = default_options
 
-    # Don't evaluate CGI ISINDEX parameters.
-    # http://hoohoo.ncsa.uiuc.edu/cgi/cl.html
-    args.clear if ENV.include?("REQUEST_METHOD")
+  # Don't evaluate CGI ISINDEX parameters.
+  # http://hoohoo.ncsa.uiuc.edu/cgi/cl.html
+  args.clear if ENV.include?("REQUEST_METHOD")
 
-    options.merge! opt_parser.parse! args
-    options[:config] = ::File.expand_path(options[:config])
-    ENV["RACK_ENV"] = options[:environment]
-    options
-  end
+  options.merge! opt_parser.parse! args
+  options[:config] = ::File.expand_path(options[:config])
+  ENV["RACK_ENV"] = options[:environment]
+  options
+end
 </ruby>
 
 With the +default_options+ set to this:
 
 <ruby>
-  def default_options
-    {
-      :environment => ENV['RACK_ENV'] || "development",
-      :pid         => nil,
-      :Port        => 9292,
-      :Host        => "0.0.0.0",
-      :AccessLog   => [],
-      :config      => "config.ru"
-    }
-  end
+def default_options
+  {
+    :environment => ENV['RACK_ENV'] || "development",
+    :pid         => nil,
+    :Port        => 9292,
+    :Host        => "0.0.0.0",
+    :AccessLog   => [],
+    :config      => "config.ru"
+  }
+end
 </ruby>
 
 There is no +REQUEST_METHOD+ key in +ENV+ so we can skip over that line. The next line merges in the options from +opt_parser+ which is defined plainly in +Rack::Server+
 
 <ruby>
-  def opt_parser
-    Options.new
-  end
+def opt_parser
+  Options.new
+end
 </ruby>
 
 The class *is* defined in +Rack::Server+, but is overwritten in +Rails::Server+ to take different arguments. Its +parse!+ method begins like this:
 
 <ruby>
-  def parse!(args)
-    args, options = args.dup, {}
+def parse!(args)
+  args, options = args.dup, {}
 
     opt_parser = OptionParser.new do |opts|
       opts.banner = "Usage: rails server [mongrel, thin, etc] [options]"
@@ -362,100 +362,101 @@ h4. +Rails::Server#start+
 This method is defined like this:
 
 <ruby>
-  def start
-    puts "=> Booting #{ActiveSupport::Inflector.demodulize(server)}"
-    puts "=> Rails #{Rails.version} application starting in #{Rails.env} on http://#{options[:Host]}:#{options[:Port]}"
-    puts "=> Call with -d to detach" unless options[:daemonize]
-    trap(:INT) { exit }
-    puts "=> Ctrl-C to shutdown server" unless options[:daemonize]
-
-    #Create required tmp directories if not found
-    %w(cache pids sessions sockets).each do |dir_to_make|
-      FileUtils.mkdir_p(Rails.root.join('tmp', dir_to_make))
-    end
-
-    super
-  ensure
-    # The '-h' option calls exit before @options is set.
-    # If we call 'options' with it unset, we get double help banners.
-    puts 'Exiting' unless @options && options[:daemonize]
+def start
+  puts "=> Booting #{ActiveSupport::Inflector.demodulize(server)}"
+  puts "=> Rails #{Rails.version} application starting in #{Rails.env} on http://#{options[:Host]}:#{options[:Port]}"
+  puts "=> Call with -d to detach" unless options[:daemonize]
+  trap(:INT) { exit }
+  puts "=> Ctrl-C to shutdown server" unless options[:daemonize]
+
+  #Create required tmp directories if not found
+  %w(cache pids sessions sockets).each do |dir_to_make|
+    FileUtils.mkdir_p(Rails.root.join('tmp', dir_to_make))
   end
+
+  super
+ensure
+  # The '-h' option calls exit before @options is set.
+  # If we call 'options' with it unset, we get double help banners.
+  puts 'Exiting' unless @options && options[:daemonize]
+end
 </ruby>
 
 This is where the first output of the Rails initialization happens. This method creates a trap for +INT+ signals, so if you +CTRL+C+ the server, it will exit the process. As we can see from the code here, it will create the +tmp/cache+, +tmp/pids+, +tmp/sessions+ and +tmp/sockets+ directories if they don't already exist prior to calling +super+. The +super+ method will call +Rack::Server.start+ which begins its definition like this:
 
 <ruby>
-  def start
-    if options[:warn]
-      $-w = true
-    end
+def start
+  if options[:warn]
+    $-w = true
+  end
 
-    if includes = options[:include]
-      $LOAD_PATH.unshift(*includes)
-    end
+  if includes = options[:include]
+    $LOAD_PATH.unshift(*includes)
+  end
 
-    if library = options[:require]
-      require library
-    end
+  if library = options[:require]
+    require library
+  end
 
-    if options[:debug]
-      $DEBUG = true
-      require 'pp'
-      p options[:server]
-      pp wrapped_app
-      pp app
-    end
+  if options[:debug]
+    $DEBUG = true
+    require 'pp'
+    p options[:server]
+    pp wrapped_app
+    pp app
+  end
+end
 </ruby>
 
 In a Rails application, these options are not set at all and therefore aren't used at all. The first line of code that's executed in this method is a call to this method:
 
 <ruby>
-  wrapped_app
+wrapped_app
 </ruby>
 
 This method calls another method:
 
 <ruby>
-  @wrapped_app ||= build_app app
+@wrapped_app ||= build_app app
 </ruby>
 
 Then the +app+ method here is defined like so:
 
 <ruby>
-  def app
-    @app ||= begin
-      if !::File.exist? options[:config]
-        abort "configuration #{options[:config]} not found"
-      end
-
-      app, options = Rack::Builder.parse_file(self.options[:config], opt_parser)
-      self.options.merge! options
-      app
+def app
+  @app ||= begin
+    if !::File.exist? options[:config]
+      abort "configuration #{options[:config]} not found"
     end
+
+    app, options = Rack::Builder.parse_file(self.options[:config], opt_parser)
+    self.options.merge! options
+    app
   end
+end
 </ruby>
 
 The +options[:config]+ value defaults to +config.ru+ which contains this:
 
 <ruby>
-  # This file is used by Rack-based servers to start the application.
+# This file is used by Rack-based servers to start the application.
 
-  require ::File.expand_path('../config/environment',  __FILE__)
-  run YourApp::Application
+require ::File.expand_path('../config/environment',  __FILE__)
+run YourApp::Application
 </ruby>
 
 
 The +Rack::Builder.parse_file+ method here takes the content from this +config.ru+ file and parses it using this code:
 
 <ruby>
-  app = eval "Rack::Builder.new {( " + cfgfile + "\n )}.to_app",
+app = eval "Rack::Builder.new {( " + cfgfile + "\n )}.to_app",
     TOPLEVEL_BINDING, config
 </ruby>
 
 The <ruby>initialize</ruby> method will take the block here and execute it within an instance of +Rack::Builder+. This is where the majority of the initialization process of Rails happens. The chain of events that this simple line sets off will be the focus of a large majority of this guide. The +require+ line for +config/environment.rb+ in +config.ru+ is the first to run:
 
 <ruby>
-  require ::File.expand_path('../config/environment',  __FILE__)
+require ::File.expand_path('../config/environment',  __FILE__)
 </ruby>
 
 h4. +config/environment.rb+
@@ -475,7 +476,7 @@ h3. Loading Rails
 The next line in +config/application.rb+ is:
 
 <ruby>
-  require 'rails/all'
+require 'rails/all'
 </ruby>
 
 h4. +railties/lib/rails/all.rb+
@@ -483,20 +484,20 @@ h4. +railties/lib/rails/all.rb+
 This file is responsible for requiring all the individual parts of Rails like so:
 
 <ruby>
-  require "rails"
+require "rails"
 
-  %w(
+%w(
     active_record
     action_controller
     action_mailer
     active_resource
     rails/test_unit
-  ).each do |framework|
-    begin
-      require "#{framework}/railtie"
-    rescue LoadError
-    end
+).each do |framework|
+  begin
+    require "#{framework}/railtie"
+  rescue LoadError
   end
+end
 </ruby>
 
 First off the line is the +rails+ require itself.
@@ -518,9 +519,9 @@ h4. +active_support/core_ext/kernel/reporting.rb+
 This is the first of the many Active Support core extensions that come with Rails. This one in particular defines methods in the +Kernel+ module which is mixed in to the +Object+ class so the methods are available on +main+ and can therefore be called like this:
 
 <ruby>
-  silence_warnings do
-    # some code
-  end
+silence_warnings do
+  # some code
+end
 </ruby>
 
 These methods can be used to silence STDERR responses and the +silence_stream+ allows you to also silence other streams. Additionally, this mixin allows you to suppress exceptions and capture streams. For more information see the "Silencing Warnings, Streams, and Exceptions":http://guides.rubyonrails.org/active_support_core_extensions.html#silencing-warnings-streams-and-exceptions section from the Active Support Core Extensions Guide.
@@ -635,14 +636,14 @@ h4. +railties/lib/rails/rack.rb+
 The final file to be loaded by +railties/lib/rails/configuration.rb+ is +rails/rack+ which defines some simple autoloads:
 
 <ruby>
-  module Rails
-    module Rack
-      autoload :Debugger,  "rails/rack/debugger"
-      autoload :Logger,    "rails/rack/logger"
-      autoload :LogTailer, "rails/rack/log_tailer"
-      autoload :Static,    "rails/rack/static"
-    end
+module Rails
+  module Rack
+    autoload :Debugger,  "rails/rack/debugger"
+    autoload :Logger,    "rails/rack/logger"
+    autoload :LogTailer, "rails/rack/log_tailer"
+    autoload :Static,    "rails/rack/static"
   end
+end
 </ruby>
 
 Once this file is finished loading, then the +Rails::Configuration+ class is initialized. This completes the loading of +railties/lib/rails/configuration.rb+ and now we jump back to the loading of +railties/lib/rails/railtie.rb+, where the next file loaded is +active_support/inflector+.
@@ -652,12 +653,12 @@ h4. +activesupport/lib/active_support/inflector.rb+
 +active_support/inflector.rb+ requires a series of file which are responsible for setting up the basics for knowing how to pluralize and singularize words. These files are:
 
 <ruby>
-  require 'active_support/inflector/inflections'
-  require 'active_support/inflector/transliterate'
-  require 'active_support/inflector/methods'
+require 'active_support/inflector/inflections'
+require 'active_support/inflector/transliterate'
+require 'active_support/inflector/methods'
 
-  require 'active_support/inflections'
-  require 'active_support/core_ext/string/inflections'
+require 'active_support/inflections'
+require 'active_support/core_ext/string/inflections'
 </ruby>
 
 The +active_support/inflector/methods+ file has already been required by +active_support/autoload+ and so won't be loaded again here.
@@ -721,22 +722,22 @@ h4. +activesupport/lib/active_support/i18n_railtie.rb+
 This file is the first file that sets up configuration with these lines inside the class:
 
 <ruby>
-  class Railtie < Rails::Railtie
-    config.i18n = ActiveSupport::OrderedOptions.new
-    config.i18n.railties_load_path = []
-    config.i18n.load_path = []
-    config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
+class Railtie < Rails::Railtie
+  config.i18n = ActiveSupport::OrderedOptions.new
+  config.i18n.railties_load_path = []
+  config.i18n.load_path = []
+  config.i18n.fallbacks = ActiveSupport::OrderedOptions.new
 </ruby>
 
 By inheriting from +Rails::Railtie+ the +Rails::Railtie#inherited+ method is called:
 
 <ruby>
-  def inherited(base)
-    unless base.abstract_railtie?
-      base.send(:include, Railtie::Configurable)
-      subclasses << base
-    end
+def inherited(base)
+  unless base.abstract_railtie?
+    base.send(:include, Railtie::Configurable)
+    subclasses << base
   end
+end
 </ruby>
 
 This first checks if the Railtie that's inheriting it is a component of Rails itself:
@@ -763,15 +764,15 @@ end
 The +config+ method used at the top of +I18n::Railtie+ is defined on +Rails::Railtie+ and is defined like this:
 
 <ruby>
-  def config
-    @config ||= Railtie::Configuration.new
-  end
+def config
+  @config ||= Railtie::Configuration.new
+end
 </ruby>
 
 At this point, that +Railtie::Configuration+ constant is automatically loaded which causes the +rails/railties/configuration+ file to be loaded. The line for this is this particular line in +railties/lib/rails/railtie.rb+:
 
 <ruby>
-  autoload :Configuration, "rails/railtie/configuration"
+autoload :Configuration, "rails/railtie/configuration"
 </ruby>
 
 h4. +railties/lib/rails/railtie/configuration.rb+
@@ -781,15 +782,15 @@ This file begins with a require out to +rails/configuration+ which has already b
 This file defines the +Rails::Railtie::Configuration+ class which is responsible for providing a way to easily configure railties and it's the +initialize+ method here which is called by the +config+ method back in the +i18n_railtie.rb+ file. The methods on this object don't exist, and so are rescued by the +method_missing+ defined further down in +configuration.rb+:
 
 <ruby>
-  def method_missing(name, *args, &blk)
-    if name.to_s =~ /=$/
-      @@options[$`.to_sym] = args.first
-    elsif @@options.key?(name)
-      @@options[name]
-    else
-      super
-    end
+def method_missing(name, *args, &blk)
+  if name.to_s =~ /=$/
+    @@options[$`.to_sym] = args.first
+  elsif @@options.key?(name)
+    @@options[name]
+  else
+    super
   end
+end
 </ruby>
 
 So therefore when an option is referred to it simply stores the value as the key if it's used in a setter context, or retrieves it if used in a getter context. Nothing fancy going on there.
@@ -799,21 +800,21 @@ h4. Back to +activesupport/lib/active_support/i18n_railtie.rb+
 After the configuration method the +reloader+ method is defined, and then the first of of Railties' initializers is defined: +i18n.callbacks+.
 
 <ruby>
-  initializer "i18n.callbacks" do
-    ActionDispatch::Reloader.to_prepare do
-      I18n::Railtie.reloader.execute_if_updated
-    end
+initializer "i18n.callbacks" do
+  ActionDispatch::Reloader.to_prepare do
+    I18n::Railtie.reloader.execute_if_updated
   end
+end
 </ruby>
 
 The +initializer+ method (from the +Rails::Initializable+ module) here doesn't run the block, but rather stores it to be run later on:
 
 <ruby>
-  def initializer(name, opts = {}, &blk)
-    raise ArgumentError, "A block must be passed when defining an initializer" unless blk
-    opts[:after] ||= initializers.last.name unless initializers.empty? || initializers.find { |i| i.name == opts[:before] }
-    initializers << Initializer.new(name, nil, opts, &blk)
-  end
+def initializer(name, opts = {}, &blk)
+  raise ArgumentError, "A block must be passed when defining an initializer" unless blk
+  opts[:after] ||= initializers.last.name unless initializers.empty? || initializers.find { |i| i.name == opts[:before] }
+  initializers << Initializer.new(name, nil, opts, &blk)
+end
 </ruby>
 
 An initializer can be configured to run before or after another initializer, which we'll see a couple of times throughout this initialization process. Anything that inherits from +Rails::Railtie+ may also make use of the +initializer+ method, something which is covered in the "Configuration guide":[http://ryanbigg.com/guides/configuring.html#rails-railtie-initializer].
@@ -821,25 +822,25 @@ An initializer can be configured to run before or after another initializer, whi
 The +Initializer+ class here is defined within the +Rails::Initializable+ module and its +initialize+ method is defined to just set up a couple of variables:
 
 <ruby>
-  def initialize(name, context, options, &block)
-    @name, @context, @options, @block = name, context, options, block
-  end
+def initialize(name, context, options, &block)
+  @name, @context, @options, @block = name, context, options, block
+end
 </ruby>
 
 Once this +initialize+ method is finished, the object is added to the object the +initializers+ method returns:
 
 <ruby>
-  def initializers
-    @initializers ||= self.class.initializers_for(self)
-  end
+def initializers
+  @initializers ||= self.class.initializers_for(self)
+end
 </ruby>
 
 If +@initializers+ isn't set (which it won't be at this point), the +intializers_for+ method will be called for this class.
 
 <ruby>
-  def initializers_for(binding)
-    Collection.new(initializers_chain.map { |i| i.bind(binding) })
-  end
+def initializers_for(binding)
+  Collection.new(initializers_chain.map { |i| i.bind(binding) })
+end
 </ruby>
 
 The +Collection+ class in +railties/lib/rails/initializable.rb+ inherits from +Array+ and includes the +TSort+ module which is used to sort out the order of the initializers based on the order they are placed in.
@@ -847,57 +848,57 @@ The +Collection+ class in +railties/lib/rails/initializable.rb+ inherits from +A
 The +initializers_chain+ method referenced in the +initializers_for+ method is defined like this:
 
 <rub>
-  def initializers_chain
-    initializers = Collection.new
-   ancestors.reverse_each do | klass |
-      next unless klass.respond_to?(:initializers)
-      initializers = initializers + klass.initializers
-    end
-    initializers
+def initializers_chain
+  initializers = Collection.new
+ ancestors.reverse_each do | klass |
+    next unless klass.respond_to?(:initializers)
+    initializers = initializers + klass.initializers
   end
+  initializers
+end
 </ruby>
 
 This method collects the initializers from the ancestors of this class and adds them to a new +Collection+ object using the <tt>+</tt> method which is defined like this for the <tt>Collection</tt> class:
 
 <ruby>
-  def +(other)
-    Collection.new(to_a + other.to_a)
-  end
+def +(other)
+  Collection.new(to_a + other.to_a)
+end
 </ruby>
 
-So this <tt>+</tt> method is overriden to return a new collection comprising of the existing collection as an array and then using the <tt>Array#+</tt> method combines these two collections, returning a "super" +Collection+ object. In this case, the only initializer that's going to be in this new +Collection+ object is the +i18n.callbacks+ initializer.
+So this <tt>+</tt> method is overridden to return a new collection comprising of the existing collection as an array and then using the <tt>Array#+</tt> method combines these two collections, returning a "super" +Collection+ object. In this case, the only initializer that's going to be in this new +Collection+ object is the +i18n.callbacks+ initializer.
 
 The next method to be called after this +initializer+ method is the +after_initialize+ method on the +config+ object, which is defined like this:
 
 <ruby>
-  def after_initialize(&block)
-    ActiveSupport.on_load(:after_initialize, :yield => true, &block)
-  end
+def after_initialize(&block)
+  ActiveSupport.on_load(:after_initialize, :yield => true, &block)
+end
 </ruby>
 
 The +on_load+ method here is provided by the +active_support/lazy_load_hooks+ file which was required earlier and is defined like this:
 
 <ruby>
-  def self.on_load(name, options = {}, &block)
-    if base = @loaded[name]
-      execute_hook(base, options, block)
-    else
-      @load_hooks[name] << [block, options]
-    end
+def self.on_load(name, options = {}, &block)
+  if base = @loaded[name]
+    execute_hook(base, options, block)
+  else
+    @load_hooks[name] << [block, options]
   end
+end
 </ruby>
 
 The +@loaded+ variable here is a hash containing elements representing the different components of Rails that have been loaded at this stage. Currently, this hash is empty. So the +else+ is executed here, using the +@load_hooks+ variable defined in +active_support/lazy_load_hooks+:
 
 <ruby>
-  @load_hooks = Hash.new {|h,k| h[k] = [] }
+@load_hooks = Hash.new {|h,k| h[k] = [] }
 </ruby>
 
 This defines a new hash which has keys that default to empty arrays. This saves Rails from having to do something like this instead:
 
 <ruby>
-  @load_hooks[name] = []
-  @load_hooks[name] << [block, options]
+@load_hooks[name] = []
+@load_hooks[name] << [block, options]
 </ruby>
 
 The value added to this array here consists of the block and options passed to +after_initialize+.
@@ -929,11 +930,11 @@ h4. +activesupport/lib/action_dispatch.rb+
 This file attempts to locate the +active_support+ and +active_model+ libraries by looking a couple of directories back from the current file and then adds the +active_support+ and +active_model+ +lib+ directories to the load path, but only if they aren't already, which they are.
 
 <ruby>
-  activesupport_path = File.expand_path('../../../activesupport/lib', __FILE__)
-  $:.unshift(activesupport_path) if File.directory?(activesupport_path) && !$:.include?(activesupport_path)
+activesupport_path = File.expand_path('../../../activesupport/lib', __FILE__)
+$:.unshift(activesupport_path) if File.directory?(activesupport_path) && !$:.include?(activesupport_path)
 
-  activemodel_path = File.expand_path('../../../activemodel/lib', __FILE__)
-  $:.unshift(activemodel_path) if File.directory?(activemodel_path) && !$:.include?(activemodel_path)
+activemodel_path = File.expand_path('../../../activemodel/lib', __FILE__)
+$:.unshift(activemodel_path) if File.directory?(activemodel_path) && !$:.include?(activemodel_path)
 </ruby>
 
 In effect, these lines only define the +activesupport_path+ and +activemodel_path+ variables and nothing more.
@@ -941,23 +942,23 @@ In effect, these lines only define the +activesupport_path+ and +activemodel_pat
 The next two requires in this file are already done, so they are not run:
 
 <ruby>
-  require 'active_support'
-  require 'active_support/dependencies/autoload'
+require 'active_support'
+require 'active_support/dependencies/autoload'
 </ruby>
 
 The following require is to +action_pack+ (+activesupport/lib/action_pack.rb+) which has a 22-line copyright notice at the top of it and ends in a simple require to +action_pack/version+. This file, like other +version.rb+ files before it, defines the +ActionPack::VERSION+ constant:
 
 <ruby>
-  module ActionPack
-    module VERSION #:nodoc:
-      MAJOR = 3
-      MINOR = 1
-      TINY  = 0
-      PRE   = "beta"
-
-      STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
-    end
+module ActionPack
+  module VERSION #:nodoc:
+    MAJOR = 3
+    MINOR = 1
+    TINY  = 0
+    PRE   = "beta"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
+end
 </ruby>
 
 Once +action_pack+ is finished, then +active_model+ is required.
@@ -967,16 +968,16 @@ h4. +activemodel/lib/active_model.rb+
 This file makes a require to +active_model/version+ which defines the version for Active Model:
 
 <ruby>
-  module ActiveModel
-    module VERSION #:nodoc:
-      MAJOR = 3
-      MINOR = 1
-      TINY  = 0
-      PRE   = "beta"
-
-      STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
-    end
+module ActiveModel
+  module VERSION #:nodoc:
+    MAJOR = 3
+    MINOR = 1
+    TINY  = 0
+    PRE   = "beta"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
+end
 </ruby>
 
 Once the +version.rb+ file is loaded, the +ActiveModel+ module has its autoloaded constants defined as well as a sub-module called +ActiveModel::Serializers+ which has autoloads of its own. When the +ActiveModel+ module is closed the +active_support/i18n+ file is required.
@@ -986,15 +987,15 @@ h4. +activesupport/lib/active_support/i18n.rb+
 This is where the +i18n+ gem is required and first configured:
 
 <ruby>
-  begin
-    require 'i18n'
-    require 'active_support/lazy_load_hooks'
-  rescue LoadError => e
-    $stderr.puts "You don't have i18n installed in your application. Please add it to your Gemfile and run bundle install"
-    raise e
-  end
+begin
+  require 'i18n'
+  require 'active_support/lazy_load_hooks'
+rescue LoadError => e
+  $stderr.puts "You don't have i18n installed in your application. Please add it to your Gemfile and run bundle install"
+  raise e
+end
 
-  I18n.load_path << "#{File.dirname(__FILE__)}/locale/en.yml"
+I18n.load_path << "#{File.dirname(__FILE__)}/locale/en.yml"
 </ruby>
 
 In effect, the +I18n+ module first defined by +i18n_railtie+ is extended by the +i18n+ gem, rather than the other way around. This has no ill effect. They both work on the same way.
@@ -1012,9 +1013,9 @@ h4. Back to +activesupport/lib/action_dispatch.rb+
 The remainder of this file requires the +rack+ file from the Rack gem which defines the +Rack+ module. After +rack+, there's autoloads defined for the +Rack+, +ActionDispatch+, +ActionDispatch::Http+, +ActionDispatch::Session+. A new method called +autoload_under+ is used here, and this simply prefixes the files where the modules are autoloaded from with the path specified. For example here:
 
 <ruby>
-  autoload_under 'testing' do
-    autoload :Assertions
-  ...
+autoload_under 'testing' do
+  autoload :Assertions
+...
 </ruby>
 
 The +Assertions+ module is in the +action_dispatch/testing+ folder rather than simply +action_dispatch+.
@@ -1046,25 +1047,25 @@ This file begins by detecting if the +lib+ directories of +active_support+ and +
 The first three requires have already been done by other files and so aren't loaded here, but the 4th require, the one to +arel+ will require the file provided by the Arel gem, which defines the +Arel+ module.
 
 <ruby>
-  require 'active_support'
-  require 'active_support/i18n'
-  require 'active_model'
-  require 'arel'
+require 'active_support'
+require 'active_support/i18n'
+require 'active_model'
+require 'arel'
 </ruby>
 
 The 5th require in this file is one to +active_record/version+ which defines the +ActiveRecord::VERSION+ constant:
 
 <ruby>
-  module ActiveRecord
-    module VERSION #:nodoc:
-      MAJOR = 3
-      MINOR = 1
-      TINY  = 0
-      PRE   = "beta"
-
-      STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
-    end
+module ActiveRecord
+  module VERSION #:nodoc:
+    MAJOR = 3
+    MINOR = 1
+    TINY  = 0
+    PRE   = "beta"
+
+    STRING = [MAJOR, MINOR, TINY, PRE].compact.join('.')
   end
+end
 </ruby>
 
 Once these requires are finished, the base for the +ActiveRecord+ module is defined along with its autoloads.
@@ -1072,9 +1073,9 @@ Once these requires are finished, the base for the +ActiveRecord+ module is defi
 Near the end of the file, we see this line:
 
 <ruby>
-  ActiveSupport.on_load(:active_record) do
-    Arel::Table.engine = self
-  end
+ActiveSupport.on_load(:active_record) do
+  Arel::Table.engine = self
+end
 </ruby>
 
 This will set the engine for +Arel::Table+ to be +ActiveRecord::Base+.
@@ -1082,7 +1083,7 @@ This will set the engine for +Arel::Table+ to be +ActiveRecord::Base+.
 The file then finishes with this line:
 
 <ruby>
-  I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml'
+I18n.load_path << File.dirname(__FILE__) + '/active_record/locale/en.yml'
 </ruby>
 
 This will add the translations from +activerecord/lib/active_record/locale/en.yml+ to the load path for +I18n+, with this file being parsed when all the translations are loaded.
@@ -1092,8 +1093,8 @@ h4. Back to +activerecord/lib/active_record/railtie.rb+
 The next two <tt>require</tt>s in this file aren't run because their files are already required, with +rails+ being required by +rails/all+ and +active_model/railtie+ being required from +action_dispatch+.
 
 <ruby>
-  require "rails"
-  require "active_model/railtie"
+require "rails"
+require "active_model/railtie"
 </ruby>
 
 The next +require+ in this file is to +action_controller/railtie+.
@@ -1103,9 +1104,9 @@ h4. +actionpack/lib/action_controller/railtie.rb+
 This file begins with a couple more requires to files that have already been loaded:
 
 <ruby>
-  require "rails"
-  require "action_controller"
-  require "action_dispatch/railtie"
+require "rails"
+require "action_controller"
+require "action_dispatch/railtie"
 </ruby>
 
 However the require after these is to a file that hasn't yet been loaded, +action_view/railtie+, which begins by requiring +action_view+.