title: Ruby module prepend vs derivation
body: <p>What are the differences between:</p>
  
  <pre><code>module Mod   
     def here
       puts 'child'
     end    
  end
  
  class A
    prepend Mod
    def here
      puts 'parent'
    end
  end
  </code></pre>
  
  <p>and</p>
  
  <pre><code>class A
     def here
       puts 'parent'
     end
  end
  
  class B &lt; A
    def here
      puts 'child'
    end
  end
  </code></pre>
  
  <p>Or another way to put it: is derivating a class the same as prepending a module of the child's code?</p>