RailsのActiveSupportのalias_method_chainを使ったRubyでの特異メソッドの上書き方法

stdout_hook_singleton_method_with_activesupport.rb

#!ruby -Ku
# override_method/stdout_hook_singleton_method_with_activesupport.rb
$KCODE = 'u'

# sample of override singleton method with active_supportlike a Rails
# alias_method_chain (ActiveSupport::CoreExtensions::Module) - APIdock
# http://apidock.com/rails/ActiveSupport/CoreExtensions/Module/alias_method_chain

require "rubygems"
require "active_support"
require "kconv"

$stdout.sync = true

class << $stdout
  def write_with_for_sjis_filter(str)
    #old_write_for_sjis_filter str.to_s.kconv(Kconv::SJIS, Kconv::UTF8)
    #old_write_for_sjis_filter str.to_s.tosjis
    # change to sjis AS IS
    write_without_for_sjis_filter NKF.nkf('-sxm0', str.to_s)
  end
  
  # same as...
  #   alias_method :write_without_for_sjis_filter, :write
  #   alias_method :write, :write_with_for_sjis_filter
  alias_method_chain :write, :for_sjis_filter
end
puts "表が怖い噂のソフト"
puts "UTF-8→SJISフックｷﾀ━（ﾟ∀ﾟ）━ !!"
puts "▶✉✦❤➡✖✔✸●■◢ ◣ ◤ ◥◧ ◨ ◩ ◪▲▼▶◀♂ ♀ ♪ ♫ ☼"
puts "テストまげもりまげもり"
puts "お前の脳天などこのテポドンキックで粉々に粉砕してやるわアアア～～～～～～！"

解説元サイト： •Rails風にActiveSupportのalias_method_chainを使う方法 - Ruby/特異メソッドの上書きと退避 - TOBY SOFT wiki