title: Get all instance variables declared in class
body: <p>Please help me get all instance variables declared in a class the same way <code>instance_methods</code> shows me all methods available in a class.</p>
  
  <pre><code>class A
    attr_accessor :ab, :ac
  end
  
  puts A.instance_methods  #gives ab and ac
  
  puts A.something         #gives me @ab @ac...
  </code></pre>