ukstudio

#!/usr/local/env ruby
# -*- coding: UTF-8 -*-
# -*- coding: EUC-JP -*-  #=> このmagic commentは無効

p "test".encoding #=> #<Encoding:UT-8>

# Magic Commentは1行目、もしくはshebangが1行目の場合は2行目の場合有効。
# Magic Commentが無い場合、US-ASCIIと判断される。
# Magic Commentの形式
#   # coding: UTF-8

ukstudio

# coding: UTF-8

str_utf = "hoge"
str_euc = "hoge".encode("EUC-JP")

# ASCII互換コーディングをもつ7bitクリーンな文字列は
# エンコーディングに関わらずASCIIとして扱える

p str_utf == str_euc #=> true
p /hoge/ =~ str_utf  #=> 0

ukstudio

# DuckTypingの単純な例
# ここで重要なのはSTDOUT(IOクラス)と
# StringIOクラスには継承関係がないとうこと。
#
require 'stringio'

def message_write(out, message)
  out.write(message)
end

ukstudio

# coding: UTF-8
class Duck; end

def foo(obj)
  raise TypeError, "アヒルじゃないです"  unless obj.is_a? Duck
end

foo(Object.new) #=> TypeError

ukstudio

# coding: UTF-8

class Logger
  def self.write(out, log)
    out.write log
  end
end

File.open("hoge", "w") do |f|
  Logger.write(f, "log") # ファイルに書き込み

ukstudio

# coding: UTF-8

class Logger
  def self.write(out, log)
    raise TypeError, "書き込めない何かだよ" unless out.respond_to? :write
    out.write log
  end
end

File.open("hoge", "w") do |f|

ukstudio

# coding: UTF-8

class Logger
  def self.write(out, log)
      out.write log
    rescue
      raise TypeError, "書き込めない何かだよ"
  end
end

ukstudio

# coding: utf-8

def profile(msg, &block)
  start_time = Time.now

  yield

  duration = Time.now - start_time
  puts msg << ": " << duration.to_s << "秒"
end

ukstudio

# coding: UTF-8

def counter_closer
  count = 0
  lambda{|n| count += n}
end

counter = counter_closer
puts counter.call(1)
puts counter.call(2)

ukstudio

#
# Railsで確認画面を実装するときのテンプレ
#

def confirm
  if request.post?
    @entry = Entry.new(params[:entry])
  else request.put?
    @entry = Entry.find(params[:id])
    @entry.attributes = params[:entry]