{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Part 3 メタプログラミング\n",
    "# 6章 Rubyのクラスオブジェクト\n",
    "# 6-1 Classクラスからクラスを作る"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "class FirstClass\n",
    "end"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-1 Classクラス"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[Class, Module, Object, Kernel, BasicObject]"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "Class.ancestors"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "[:new, :allocate, :superclass]"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "Class.instance_methods(false)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "Module"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "Class.superclass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-2 Class.new"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "<main>: warning: already initialized constant FirstClass\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "FirstClass2"
      ]
     },
     "execution_count": 8,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "FirstClass = Class.new\n",
    "FirstClass2 = Class.new"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 9,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"FirstClass2\""
      ]
     },
     "execution_count": 9,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "first_class_instance = FirstClass2.new\n",
    "first_class_instance.class.name"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-3 クラスの継承"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "FirstClass"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "SecondClass = Class.new(FirstClass)\n",
    "SecondClass.superclass"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-4 メソッドを定義する"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "true\n",
      "#<ThirdClass:0x00007fb8529740c0>\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       ":hello"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "klass_object = nil\n",
    "\n",
    "ThirdClass = Class.new do |klass|\n",
    "  klass_object = klass\n",
    "  klass == self\n",
    "  \n",
    "  def hello\n",
    "    :hello\n",
    "  end\n",
    "end\n",
    "\n",
    "p klass_object == ThirdClass\n",
    "\n",
    "p third_class_instance = ThirdClass.new\n",
    "third_class_instance.hello"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "#<ThirdClass:0x00007fb852395230>"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "tci = klass_object.new"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       ":hello"
      ]
     },
     "execution_count": 13,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "tci.hello"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-5 クラス名の無いクラス"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "nil\n"
     ]
    }
   ],
   "source": [
    "klass = Class.new\n",
    "p klass.name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "#<Class:0x00007fb85235d240>\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "#<Class:0x00007fb85235d240>"
      ]
     },
     "execution_count": 16,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "obj = klass.new\n",
    "p obj.class"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"NamedClass\""
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "NamedClass = klass\n",
    "klass.name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"NamedClass\""
      ]
     },
     "execution_count": 18,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "UnknownClass = klass\n",
    "klass.name"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "\"NamedClass\""
      ]
     },
     "execution_count": 19,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "UnknownClass.name"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "### 6-1-6 class定義式とClass.new"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "ename": "NameError",
     "evalue": "undefined local variable or method `external_scope' for ExpDefineClass:Class",
     "output_type": "error",
     "traceback": [
      "\u001b[31mNameError\u001b[0m: undefined local variable or method `external_scope' for ExpDefineClass:Class",
      "\u001b[37m<main>:3:in `<class:ExpDefineClass>'\u001b[0m",
      "\u001b[37m<main>:2:in `<main>'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/backend.rb:44:in `eval'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/backend.rb:44:in `eval'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/backend.rb:12:in `eval'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/kernel.rb:87:in `execute_request'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/kernel.rb:47:in `dispatch'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/kernel.rb:37:in `run'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/command.rb:70:in `run_kernel'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/lib/iruby/command.rb:34:in `run'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/iruby-0.3/bin/iruby:5:in `<top (required)>'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/bin/iruby:23:in `load'\u001b[0m",
      "\u001b[37m/Users/ariga/.rbenv/versions/2.5.1/bin/iruby:23:in `<main>'\u001b[0m"
     ]
    }
   ],
   "source": [
    "external_scope = 1\n",
    "\n",
    "class ExpDefineClass\n",
    "  puts external_scope\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "NewDefineClass"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "NewDefineClass = Class.new do\n",
    "  puts external_scope\n",
    "end"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Ruby 2.5.1",
   "language": "ruby",
   "name": "ruby"
  },
  "language_info": {
   "file_extension": ".rb",
   "mimetype": "application/x-ruby",
   "name": "ruby",
   "version": "2.5.1"
  }
 },
 "nbformat": 4,
 "nbformat_minor": 2
}