ruby extend¡¢include¡¢prependdzÎö

includeÓëextend

module A
  def my_method
    'method in module A'
  end
end

class B
  include A
end

class C
  extend A
end

puts B.new.my_method #=> method in module A
# puts C.new.my_method # error undefined method
puts C.my_method  # => method in module A

p B.ancestors #[B, A, Object, Kernel, BasicObject]
p C.ancestors #whitout A,  [C, Object, Kernel, BasicObject]

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prepend Óë include

module A
  def my_method
    'method in module A'
  end
end

class B
  include A
end

class C
  prepend A
end

puts B.new.my_method
puts C.new.my_method 

p B.ancestors #=> [B, A, Object, Kernel, BasicObject]
p C.ancestors #=> [A, C, Object, Kernel, BasicObject]

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include

module A1
end
module A2
  include A1
end
class B
  include A2
end

p B.ancestors #=> [B, A2, A1, Object, Kernel, BasicObject]