def welcome
  puts "Welcome to my Lightningtalk!"
  author = "Grecia Delgado"
  theme = "Useful built-in methods of Object class in Ruby"
end 

print welcome

Object.class 
# Class
Array.class
# Class
Numeric.class
# Class
Class.class
# Class
Object.ancestors
# [Object, Kernel, BasicObject]
Array.ancestors
# [Array, Enumerable, Object, Kernel, BasicObject]
Numeric.ancestors
#[Numeric, Comparable, Object, Kernel, BasicObject]
Class.ancestors
#[Class, Module, Object, Kernel, BasicObject]
Kernel.class
# Module
BasicObject.class
#Class
Object.instance_methods
=> [:dup, :itself, :yield_self, :then, :taint, :tainted?, :untaint, :untrust, 
  :untrusted?, :trust, :frozen?, :methods, :singleton_methods, :protected_methods, 
  :private_methods, :public_methods, :instance_variables, :instance_variable_get, 
  :instance_variable_set, :instance_variable_defined?, :remove_instance_variable, :instance_of?, 
  :kind_of?, :is_a?, :tap, :class, :singleton_class, :display, :clone, :hash, :public_send, :method, 
  :public_method, :singleton_method, :define_singleton_method, :extend, :to_enum, :enum_for, 
  :<=>, :===, :=~, :!~, :nil?, :eql?, :respond_to?, :freeze, :inspect, :object_id, :send, :to_s, :__send__, 
  :!, :==, :!=, :equal?, :__id__, :instance_eval, :instance_exec]

Kernel.instance_methods
=>[:dup, :itself, :yield_self, :then, :taint, :tainted?, :untaint, :untrust, :untrusted?, :trust, 
  :frozen?, :methods, :singleton_methods, :protected_methods, :private_methods, :public_methods, 
  :instance_variables, :instance_variable_get, :instance_variable_set, :instance_variable_defined?, 
  :remove_instance_variable, :instance_of?, :kind_of?, :is_a?, :tap, :class, :singleton_class, :display, 
  :clone, :hash, :public_send, :method, :public_method, :singleton_method, :define_singleton_method, 
  :extend, :to_enum, :enum_for, :<=>, :===, :=~, :!~, :nil?, :eql?, :respond_to?, :freeze, :inspect, 
  :object_id, :send, :to_s]

# el metodo retorna true or False
# Retorna true si el Obj es una instacia la clase dada
class Mascotas
end

class Gato < Mascotas
end

class GatoSilvestre < Gato
end

mishi = Gato.new

mishi.instance_of? Mascotas #=> false
mishi.instance_of? Gato #=> true
mishi.instance_of? GatoSilvestre #=> false

# el metodo retorna true or False
# Retorna true si Obj && instancia comparten clase||módulo 
module Mamifero 
end

class Mascotas
	include Mamifero 
end

class Gato < Mascotas
end

class GatoSilvestre < Gato
end

mishi = Mascotas.new

mishi.is_a? Mascotas #=> true
mishi.is_a? Gato #=> false
mishi.is_a? GatoSilvestre #=> false
mishi.is_a? Mamifero #=> true

# Invoca el método identificado a través de un símbolo, 
# pasándole los argumentos especificados

class MathOperations
  def expo(num1, num2)
    num1**num2
  end

  def sum (num1, num2, num3)
    num1 + num2 + num3
  end
end

expo = MathOperations.new 
sum = MathOperations.new 

expo.send :expo, 2,3 #retorna 8
sum.send :sum,5,5,6 #retorna 16

# Agrega a los obj los métodos de instancia 
# de cada módulo dado como parámetro.

module Universo
  def say_hello
    "Hola desde el universo"
  end
end

class Planeta
  def message
    "Hola desde el planeta"
  end
end

saludo = Planeta.new
saludo.message  #=> "Hola desde el planeta"
saludo.extend(say_hello) #<Planeta:0x0000558f8b8f17e8>
saludo.say_hello #=>"Hola desde el universo"

# el .clone clona el Obj junto con 
# todas variables de instancia

class Cities
  attr_accessor :food
  
  def traffic
  	"it's chaotic!"
  end
end

city1 = Cities.new
city1.food = "ceviche"
city1.inspect #<Cities:0x0000558f8b8135d8 @food=\"ceviche\">
city1.traffic #"it's chaotic!"

city2 = city1.clone
city2.inspect #"#<Cities:0x0000558f8b845768 @food=\"ceviche\">"
city2.traffic #"it's chaotic!"

# Elimina la variable de instancia nombrada de obj, 
# devolviendo el valor de esa variable.

class Persons
  attr_reader :age, :heigth , :job 
  def initialize
    @job = "carpintero"
  end
  def remove
    remove_instance_variable(:@job)
  end
end

person = Persons.new
person.job      #=> "carpintero"
person.remove   #=> "carpintero"
person.job      #=> nil