How to get attributes that were defined through attr_reader or attr_accessor

Question

Suppose I have a class A

class A
  attr_accessor :x, :y

  def initialize(x,y)
    @x, @y = x, y
  end
end

How can I get

Answer 1

when you use attr_accessor to define attributes in a class, Ruby using refexion, define a couple of methods, for each attribute declared, one to get the value and other to set, an instance variable of the same name of the attribute

you can see this methods using

p A.instance_methods

[:x, :x=, :y, :y=, :nil?, :===, :=~, :!~, :eql?, :hash, :<=>, :class, :singleton_class, :clone, :dup, :initialize_dup, :initialize_clone, :taint, :tainted?, :untaint, :untrust, :untrusted?,..

So this attributes are accesible, outside the class, with

p "#{a.x},#{a.y}"

or inside the class through the corresponding instance variable

class A
  ...
  def attributes
    [@x,@y]
  end
  ...
end
p a.attributes   #=> [5,10]