exception_hierarchy_test.rb

module Less
  class Error <  ::StandardError

    def initialize(msg)
      puts "<<<<" + msg + ">>>>"
      super(msg)
    end
    
  end


  class StandardError < Exception
    def initialize(msg)
      puts "BAD BAD BAD"
      super(msg)
    end
  end
end


class Awesome
  include Less


  def something
    raise Error, "This is bad bad bad"
  end
  
end


a = Awesome.new

a.something

Result

<<<<This is bad bad bad>>>>
/Users/anil.wadghule/Code/ruby/exception_hierarchy_test.rb:26:in `something': This is bad bad bad (Less::Error)
	from /Users/anil.wadghule/Code/ruby/exception_hierarchy_test.rb:34:in `<main>'