class Monkey
    def eat
        puts "i have banana"
    end
end
monkey = Monkey.new
class Monkey
    def eat
        puts "I have apple"
    end
end
monkey.eat

[Running] ruby "/Users/edmond/Desktop/Monkey.rb"
I have apple

module Pod
  module Downloader
    # ...
  end
end

module Pod
  module Downloader
    module API
      def execute_command(executable, command, raise_on_failure = false)
        # ...
      end
      # ...
  end
end

$ pod
Usage:
    $ pod COMMAND
      CocoaPods, the Cocoa library package manager.
Commands:
    + cache               Manipulate the CocoaPods cache
    + deintegrate         Deintegrate CocoaPods from your project
    + env                 Display pod environment
    + init                Generate a Podfile for the current directory
   ...
Options:
    --allow-root          Allows CocoaPods to run as root
    --silent              Show nothing
    --version             Show the version of the tool
    ...

module CLAide
  VERSION = '1.0.3'.freeze
  require 'claide/ansi'
  require 'claide/argument'
  require 'claide/argv'
  require 'claide/command'
  require 'claide/help'
  require 'claide/informative_error'
end

$ pod update --help
Usage:
    $ pod update [POD_NAMES ...]
        Updates the Pods identified by the specified `POD_NAMES`
Options:
    --verbose                              Show more debugging information
    --no-ansi                              Show output without ANSI codes
    --help                                 Show help banner of specified command

module Pod
  class Command
    class Update < Command
      self.arguments = [
        CLAide::Argument.new('POD_NAMES', false, true),
      ]

      self.description = <<-DESC
        Updates the Pods identified by the specified `POD_NAMES`.
      DESC

      def self.options
        [
          ["--sources", 'The sources from which to update dependent pods'],
          ['--exclude-pods', 'Pods to exclude during update'],
          ['--clean-install', 'Ignore the contents of the project cache and force a full pod installation']
        ].concat(super)
      end
    end
  end
end

self.abstract_command = true

module Pod
  class Command < CLAide::Command
    require 'cocoapods/command/install' # 1
    require 'cocoapods/command/update'
    # ...
    self.abstract_command = true
    self.command = 'pod'
    # ...
end

self.arguments = [
    CLAide::Argument.new('POD_NAMES', false, true),
]

module CLAide
  class Argument

    def initialize(names, required, repeatable = false)
      @names = Array(names)
      @required = required
      @repeatable = repeatable
    end
end

$ pod update Alamofire, SwiftyJSON

def self.run(argv = [])
    # 根据文件前缀来匹配对应的插件
    plugin_prefixes.each do |plugin_prefix|
       PluginManager.load_plugins(plugin_prefix)
    end
    argv = ARGV.coerce(argv)
    # 解析 argument 生成对应的 command instance
    command = parse(argv) 
    ANSI.disabled = !command.ansi_output?
    unless command.handle_root_options(argv)
       command.validate!
       command.run
    end
rescue Object => exception
    handle_exception(command, exception)
end

def run
    raise 'A subclass should override the `CLAide::Command#run` method to ' \
    'actually perform some work.'
end

def self.parse(argv)
  # 通过解析 argv 获取到与 cmd 名称
    argv = ARGV.coerce(argv)
    cmd = argv.arguments.first
    # 如果 cmd 对应的 Command 类，则更新 argv，继续解析命令
    if cmd && subcommand = find_subcommand(cmd)
        argv.shift_argument
        subcommand.parse(argv)
    # 如果 cmd 为抽象命令且指定了默认命令，则返回默认命令继续解析参数
    elsif abstract_command? && default_subcommand
        load_default_subcommand(argv)
    else
        # 初始化真正的 cmd 实例
        new(argv)
    end
end

def self.inherited(subcommand)
    subcommands << subcommand
end

module Parser
    def self.parse(argv)
        entries = []
        copy = argv.map(&:to_s)
        double_dash = false
        while argument = copy.shift
          next if !double_dash && double_dash = (argument == '--')
          type = double_dash ? :arg : argument_type(argument)
          parsed_argument = parse_argument(type, argument)
          entries << [type, parsed_argument]
        end
        entries
    end
    # ,,,
end

pod update Alamofire --no-repo-update --exclude-pods=SwiftyJSON

[
    [:arg, "Alamofire"],
    [:flag, ["repo-update", false]],
    [:option, ["exclude-pods", "SwiftyJSON"]]
]

class String
      def ansi
        CLAide::ANSI::StringEscaper.new(self)
      end
    end

"example".ansi.yellow #=> "\e[33mexample\e[39m"
"example".ansi.on_red #=> "\e[41mexample\e[49m"
"example".ansi.bold   #=> "\e[1mexample\e[21m"

def prettify_title(title)
  title.ansi.underline
end
def prettify_subcommand(name)
  name.chomp.ansi.green
end
def prettify_option_name(name)
  name.chomp.ansi.blue
end

def self.load_plugins(plugin_prefix)
    loaded_plugins[plugin_prefix] ||=
    plugin_gems_for_prefix(plugin_prefix).map do |spec, paths|
        spec if safe_activate_and_require(spec, paths)
    end.compact
end

def self.plugin_gems_for_prefix(prefix)
    glob = "#{prefix}_plugin#{Gem.suffix_pattern}"
    Gem::Specification.latest_specs(true).map do |spec|
        matches = spec.matches_for_glob(glob)
        [spec, matches] unless matches.empty?
    end.compact
end

def self.safe_activate_and_require(spec, paths)
    spec.activate
    paths.each { |path| require(path) }
    true
rescue Exception => exception
    # ...
end

self.plugin_prefixes = %w(claide cocoapods)

.
├── BeverageMaker.gemspec
│   # ...
├── exe
│   └── beverage-maker
├── lib
│   ├── beveragemaker
│   │   ├── command
│   │   │   ├── coffee.rb # 包含 abstract command 以及用于制作不同咖啡的 normal command
│   │   │   ├── maker.rb  # Command 抽象类
│   │   │   └── tea.rb    # normal command, 不同种类的 ???? 通过参数配置来完成
│   │   ├── command.rb
│   │   └── version.rb
│   └── beveragemaker.rb
└── spec
    ├── BeverageMaker_spec.rb
    └── spec_helper.rb

$ bundle gem BeverageMaker
Creating gem 'BeverageMaker'...
MIT License enabled in config
Code of conduct enabled in config
      create  BeverageMaker/Gemfile
      create  BeverageMaker/lib/BeverageMaker.rb
      create  BeverageMaker/lib/BeverageMaker/version.rb
      create  BeverageMaker/BeverageMaker.gemspec
      create  BeverageMaker/Rakefile
      # ...
Initializing git repo in ~/$HOME/Desktop/BeverageMaker
Gem 'BeverageMaker' was successfully created. For more information on making a RubyGem visit https://bundler.io/guides/creating_gem.html

require_relative 'lib/BeverageMaker/version'
Gem::Specification.new do |spec|
  spec.name          = "BeverageMaker"
  spec.version       = BeverageMaker::VERSION
  spec.authors       = ["Edmond"]
  spec.email         = ["chun574271939@gmail.com"]
  spec.summary       = "BeverageMaker"
  spec.description   = "BeverageMaker"
  spec.homepage      = "https://looseyi.github.io"
  spec.license       = "MIT"
  spec.required_ruby_version = Gem::Requirement.new(">= 2.3.0")
  spec.metadata["allowed_push_host"] = "https://looseyi.github.io"
  spec.metadata["homepage_uri"] = spec.homepage
  spec.metadata["source_code_uri"] = "https://looseyi.github.io"
  spec.metadata["changelog_uri"] = "https://looseyi.github.io"
  spec.files         = Dir.chdir(File.expand_path('..', __FILE__)) do
    `git ls-files -z`.split("\x0").reject { |f| f.match(%r{^(test|spec|features)/}) }
  end
  # 1
  spec.bindir        = "exe"
  spec.executables   = "beverage-maker"
  spec.require_paths = ["lib"]

  spec.add_runtime_dependency 'claide',         '>= 1.0.2', '< 2.0'
  spec.add_runtime_dependency 'colored2',       '~> 3.1'
end

spec.bindir        = "exe"
spec.executables   = "beverage-maker"

#!/usr/bin/env ruby
require 'beveragemaker'
BeverageMaker::Command.run(ARGV)

require 'claide'
require 'colored2'
module BeverageMaker
  # 引入具体的 coffee & tea maker
  require 'beveragemaker/command/coffee'
  require 'beveragemaker/command/tea'

  class Command < CLAide::Command
    self.command = 'beverage-maker'  
    self.abstract_command = true   
    self.description = 'Make delicious beverages from the comfort of your terminal.'
    def self.options
      [
        ['--no-milk', 'Don’t add milk to the beverage'],
        ['--sweetener=[sugar|honey]', 'Use one of the available sweeteners'],
      ].concat(super)
    end

    def initialize(argv)
      @add_milk = argv.flag?('milk', true)
      @sweetener = argv.option('sweetener')
      super
    end

    def validate!
      super
      if @sweetener && !%w(sugar honey).include?(@sweetener)
        help! "`#{@sweetener}' is not a valid sweetener."
      end
    end

    def run
      puts '* Boiling water…'
      sleep 1
      if @add_milk
        puts '* Adding milk…'
        sleep 1
      end
      if @sweetener
        puts "* Adding #{@sweetener}…"
        sleep 1
      end
    end
  end
end

class Coffee < Command
    # ...
    self.abstract_command = true
    def run
        super
        puts "* Grinding #{self.class.command} beans…"
        sleep 1
        puts '* Brewing coffee…'
        sleep 1
        puts '* Enjoy!'
    end
    class BlackEye < Coffee
        self.summary = 'A Black Eye is dripped coffee with a double shot of ' \
        'espresso'
    end
    # ...
end

class Tea < Command
    # ...
    self.arguments = [
      CLAide::Argument.new('FLAVOR', true),
    ]
    def self.options
      [['--iced', 'the ice-tea version']].concat(super)
    end
    def initialize(argv)
      @flavor = argv.shift_argument
      @iced = argv.flag?('iced')
      super
    end
    def validate!
      super
      if @flavor.nil?
        help! 'A flavor argument is required.'
      end
      unless %w(black green oolong white).include?(@flavor)
        help! "`#{@flavor}' is not a valid flavor."
      end
    end
  # ...
end

gem build *.gemspec
gem install *.gem

$ gem build *.gemspec
WARNING:  description and summary are identical
WARNING:  See http://guides.rubygems.org/specification-reference/ for help
  Successfully built RubyGem
  Name: BeverageMaker
  Version: 0.1.0
  File: BeverageMaker-0.1.0.gem

$ gem install *.gem
Successfully installed BeverageMaker-0.1.0
Parsing documentation for BeverageMaker-0.1.0
Done installing documentation for BeverageMaker after 0 seconds
1 gem installed

$ beverage-maker
Usage:
    $ beverage-maker COMMAND
      Make delicious beverages from the comfort of yourterminal.
Commands:
    + coffee                    Drink brewed from roasted coffee beans
Options:
    --no-milk                   Don’t add milk to the beverage
    --sweetener=[sugar|honey]   Use one of the available sweeteners
    --version                   Show the version of the tool
    --verbose                   Show more debugging information
    --no-ansi                   Show output without ANSI codes
    --help                      Show help banner of specified command

$ beverage-maker coffee black-eye
* Boiling water…
* Adding milk…
* Grinding black-eye beans…
* Brewing coffee…
* Enjoy!

target 'Demo' do
 pod 'Alamofire', :path => './Alamofire'
end

module Pod
  require 'cocoapods-core/gem_version'
  class PlainInformative < StandardError; end
  class Informative < PlainInformative; end
  require 'pathname'
  require 'cocoapods-core/vendor'

  # 用于存储 PodSpec 中的版本号
  autoload :Version,        'cocoapods-core/version'
  # pod 的版本限制
  autoload :Requirement,    'cocoapods-core/requirement'
  # 配置 Podfile 或 PodSpec 中的 pod 依赖
  autoload :Dependency,     'cocoapods-core/dependency'
  # 获取 Github 仓库信息
  autoload :GitHub,         'cocoapods-core/github'
  # 处理 HTTP 请求
  autoload :HTTP,           'cocoapods-core/http'
  # 记录最终 pod 的依赖信息
  autoload :Lockfile,       'cocoapods-core/lockfile'
  # 记录 SDK 的名称和 target 版本
  autoload :Platform,       'cocoapods-core/platform'
  # 对应 Podfile 文件的 class
  autoload :Podfile,        'cocoapods-core/podfile'
  # 管理 PodSpec 的集合
  autoload :Source,         'cocoapods-core/source'
  # 管理基于 CDN 来源的 PodSpec 集合
  autoload :CDNSource,      'cocoapods-core/cdn_source'
  # 管理基于 Trunk 来源的 PodSpec 集合
  autoload :TrunkSource,    'cocoapods-core/trunk_source'
  # 对应 PodSpec 文件的 class
  autoload :Specification,  'cocoapods-core/specification'
  # 将 pod 信息转为 .yml 文件，用于 lockfile 的序列化
  autoload :YAMLHelper,     'cocoapods-core/yaml_helper'
  # 记录 pod 依赖类型，是静态库/动态库
  autoload :BuildType,      'cocoapods-core/build_type'

  ...
  Spec = Specification
end

module Pod
  class Podfile
    class TargetDefinition
      # 父节点: TargetDefinition 或者 Podfile
      attr_reader :parent
      # 子节点: TargetDefinition
      attr_reader :children
      # 记录 tareget 的配置信息
      attr_accessor :internal_hash
      def root?
        parent.is_a?(Podfile) || parent.nil?
      end
      def root
        if root?
          self
        else
          parent.root
        end
      end
      def podfile
        root.parent
      end

      # ...
    end
  end
end

require 'cocoapods-core/podfile/dsl'
require 'cocoapods-core/podfile/target_definition'
module Pod
  class Podfile
    include Pod::Podfile::DSL
    # podfile 路径
    attr_accessor :defined_in_file
    # 所有的 TargetDefinition 的根节点, 正常只有一个，即 Pods.project target
    attr_accessor :root_target_definitions
    # 记录 Pods.project 项目的配置信息
    attr_accessor :internal_hash
    # 当前 DSL 解析使用的 TargetDefinition
    attr_accessor :current_target_definition
    # ...
  end
end

PODS:
      - Alamofire (4.6.0)
    DEPENDENCIES:
      - Alamofire (from `./Alamofire`)
    EXTERNAL SOURCES:
      Alamofire:
        :path: "./Alamofire"
    SPEC CHECKSUMS:
      Alamofire: 0dda98a0ed7eec4bdcd5fe3cdd35fcd2b3022825
    PODFILE CHECKSUM: da12cc12a30cfb48ebc5d14e8f51737ab65e8241
    COCOAPODS: 1.10.0.beta.2

PODFILE_NAMES = [
   'CocoaPods.podfile.yaml',
   'CocoaPods.podfile',
   'Podfile',
   'Podfile.rb',
].freeze

module Pod
  class Podfile
    include Pod::Podfile::DSL
    def self.from_file(path)
      path = Pathname.new(path)
      unless path.exist?
        raise Informative, "No Podfile exists at path `#{path}`."
      end
      # 这里我们可以看出，Podfile 目前已经支持了结尾是 .podfile 和 .rb 后缀的文件名
      # 其实是为了改善很多编译器使用文件后缀来确认 filetype，比如 vim
      # 相比与 Podfile 这个文件名要更加的友好
      case path.extname
      when '', '.podfile', '.rb'
        Podfile.from_ruby(path)
      when '.yaml'
        # 现在也支持了 .yaml 格式
        Podfile.from_yaml(path)
      else
        raise Informative, "Unsupported Podfile format `#{path}`."
      end
    end
end

def verify_podfile_exists!
    unless config.podfile
        raise Informative, "No `Podfile' found in the project directory."
    end
end

def podfile_path_in_dir(dir)
    PODFILE_NAMES.each do |filename|
        candidate = dir + filename
        if candidate.file?
        return candidate
        end
    end
    nil
end
def podfile_path
    @podfile_path ||= podfile_path_in_dir(installation_root)
end
def podfile
    @podfile ||= Podfile.from_file(podfile_path) if podfile_path
end

def self.from_ruby(path, contents = nil)
    # ①
    contents ||= File.open(path, 'r:utf-8', &:read)
    # 兼容 1.9 版本的 Rubinius 中的编码问题
    if contents.respond_to?(:encoding) && contents.encoding.name != 'UTF-8'
        contents.encode!('UTF-8')
    end
    # 对 Podfile 中不规范的单引号或双引号进行检查，并进行自动修正，及抛出错误
    if contents.tr!('“”‘’‛', %(""'''))
        CoreUI.warn "..."
    end
    # ②
    podfile = Podfile.new(path) do
        begin
         eval(contents, nil, path.to_s)
        rescue Exception => e
         message = "Invalid `#{path.basename}` file: #{e.message}"
         raise DSLError.new(message, path, e, contents)
        end
    end
    podfile
end

eval(contents, nil, path.to_s)

def initialize(defined_in_file = nil, internal_hash = {}, &block)
    self.defined_in_file = defined_in_file
    @internal_hash = internal_hash
    if block
        default_target_def = TargetDefinition.new('Pods', self)
        default_target_def.abstract = true
        @root_target_definitions = [default_target_def]
        @current_target_definition = default_target_def
        instance_eval(&block)
    else
        @root_target_definitions = []
    end
end

def self.from_yaml(path)
    string = File.open(path, 'r:utf-8', &:read)

    # 为了解决 Rubinius incomplete encoding in 1.9 mode
   # https://github.com/rubinius/rubinius/issues/1539
    if string.respond_to?(:encoding) && string.encoding.name != 'UTF-8'
        string.encode!('UTF-8')
    end
    hash = YAMLHelper.load_string(string)
    from_hash(hash, path)
end

def self.from_hash(hash, path = nil)
    internal_hash = hash.dup
    target_definitions = internal_hash.delete('target_definitions') || []
    podfile = Podfile.new(path, internal_hash)
    target_definitions.each do |definition_hash|
        definition = TargetDefinition.from_hash(definition_hash, podfile)
        podfile.root_target_definitions << definition
    end
    podfile
end

target 'Example' do
 pod 'Alamofire'
end

def pod(name = nil, *requirements)
    unless name
        raise StandardError, 'A dependency requires a name.'
    end
    current_target_definition.store_pod(name, *requirements)
end

pod 'Alamofire', '0.9'
pod 'Alamofire', :modular_headers => true
pod 'Alamofire', :configurations => ['Debug', 'Beta']
pod 'Alamofire', :source => 'https://github.com/CocoaPods/Specs.git'
pod 'Alamofire', :subspecs => ['Attribute', 'QuerySet']
pod 'Alamofire', :testspecs => ['UnitTests', 'SomeOtherTests']
pod 'Alamofire', :path => '~/Documents/AFNetworking'
pod 'Alamofire', :podspec => 'https://example.com/Alamofire.podspec'
pod 'Alamofire', :git => 'https://github.com/looseyi/Alamofire.git', :tag => '0.7.0'

def store_pod(name, *requirements)
  return if parse_subspecs(name, requirements) # This parse method must be called first
  parse_inhibit_warnings(name, requirements)
  parse_modular_headers(name, requirements)
  parse_configuration_whitelist(name, requirements)
  parse_project_name(name, requirements)
  if requirements && !requirements.empty?
    pod = { name => requirements }
  else
    pod = name
  end
  get_hash_value('dependencies', []) << pod
  nil
end

def get_hash_value(key, base_value = nil)
  unless HASH_KEYS.include?(key)
    raise StandardError, "Unsupported hash key `#{key}`"
  end
  internal_hash[key] = base_value if internal_hash[key].nil?
  internal_hash[key]
end

def set_hash_value(key, value)
  unless HASH_KEYS.include?(key)
    raise StandardError, "Unsupported hash key `#{key}`"
  end
  internal_hash[key] = value
end

## freeze 表示该数组不可修改。另外，%w 用于表示其中元素被单引号括起的数组。 
# %W(#{foo} Bar Bar\ with\ space) => ["Foo", "Bar", "Bar with space"] 
# 对应的还有 %W 表示其中元素被双引号括起的数组。
HASH_KEYS = %w(
    name
    platform
    podspecs
    exclusive
    link_with
    link_with_first_target
    inhibit_warnings
    use_modular_headers
    user_project_path
    build_configurations
    project_names
    dependencies
    script_phases
    children
    configuration_pod_whitelist
    uses_frameworks
    swift_version_requirements
    inheritance
    abstract
    swift_version
).freeze

target 'Demo1' do
  pod 'Alamofire'
  target 'Demo2' do
    target 'Demo3' do
    end
  end
end

target 'Demo1' do
  pod 'Alamofire'
  target 'Demo2' do
    pod 'RxSwift'
  end
  target 'Demo3' do
   pod 'SwiftyJSON'
  end
end

abstract_target 'Networking' do
  pod 'Alamofire'
  target 'Demo1' do
    pod 'RxSwift'
  end
  target 'Demo2' do
    pod 'ReactCocoa'
  end
  target 'Demo3' do
  end
end

; 将 f1 设置为表达式 (+ 1 2 3)
(define f1 '(+ 1 2 3))

; 执行 f1 (+ 1 2 3) 这个表达式，并返回 6
(eval f1 user-initial-environment)

# Lisp 中
(loop (print (eval (read))))
# Ruby 中
while [case]
  print(eval(read))
end

str = 'Hello'
puts eval("str + ' CocoaPods'") # Hello CocoaPods

def self.from_ruby(path, contents = nil)
  # ... 
  podfile = Podfile.new(path) do
    begin
      # 执行 Podfile 中的逻辑
      eval(contents, nil, path.to_s)
    rescue Exception => e
      message = "Invalid `#{path.basename}` file: #{e.message}"
      raise DSLError.new(message, path, e, contents)
    end
  end
  podfile
end

def foo 
  name = 'Gua'
  binding
end
eval('p name', foo) # Gua

@a = "Hello"
class Addition
  def add
    TOPLEVEL_BINDING.eval("@a += ' Gua'")
  end
end
Addition.new.add
p TOPLEVEL_BINDING.receiver # main
p @a # Hello Gua

class Foo
      def m1
        puts "m1"
      end
    end

    class Foo
      def m2 
        puts "m2"
      end
    end

    Foo.new.m1 # m1
    Foo.new.m2 # m2

    class Foo
      def m1
        puts "m1 new"
      end
    end

    Foo.new.m1 # m1 new
    Foo.new.m2 # m2

class Foo
  def m1
    puts "m1"
  end
end

foo1 = Foo.new

def foo1.m2()
  puts "m2"
end

foo1.m1 # m1
foo1.m2 # m2
foo2 = Foo.new
foo2.m1 # m1
# foo2.m2 undefined method `m2' for #<Foo:0x00007f88bb08e238> (NoMethodError)

class Foo
  def m1
    puts "m1"
  end
end

foo = Foo.new
foo.m1 # m1

class Foo
  alias :origin_m1 :m1
  def m1
    origin_m1
    puts "Hook it!"
  end
end

foo.m1 
# m1
# Hook it!

class Foo
  def m1
    puts "m1"
  end
end

foo = Foo.new
foo.m1 # m1

"""
定义一个 Patch
"""
module TemproaryPatch
  refine Foo do 
    def m1 
      puts "m1 bugfix"
    end
  end
end

using TemproaryPatch
foo2 = Foo.new
foo2.m1 # m1 bugfix