puts_methods.rb

module PutsMethods
  module_function
  # prints out methods in a pretty way. e.g.:
  #   >> PutsMethods "asdf"
  #   String
  #       <=>, ==, ===, eql?, hash, casecmp, ...
  #   Comparable
  #       >, >=, <, <=, between?
  #   ...
  def puts(object, type: 'public')
    method_names = object.public_send("#{type}_methods")
    method_objects = method_names.map do |name|
      # Use Kernel.method in case the object has its own method named "method"
      Kernel.method(:method).unbind.bind(object).call(name)
    end
    method_mapping = method_objects.group_by(&:owner)

    rows = method_mapping.map do |owner, methods|
      "#{owner}\n    " + methods.map(&:name).join(", ")
    end

    $stdout.puts rows.join("\n\n")
  end
end

module Kernel
  module_function
  def PutsMethods(object, type: 'public')
    PutsMethods.puts(object, type: type)
  end
end