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!