How can I override Hash native brackets ([] access)

This seems to get the job done.

class Hash
  def [](key)
    value = (fetch key, nil) || (fetch key.to_s, nil) || (fetch key.to_sym, nil)     
  end

  def []=(key,val)
    if (key.is_a? String) || (key.is_a? Symbol) #clear if setting str/sym
        self.delete key.to_sym
        self.delete key.to_s        
    end
    merge!({key => val})
  end
end

And now:

user = {name: 'Joe', 'age' => 20} #literal hash with both symbols and strings as keys
user['name'] == 'Joe' # cool!
user[:age] == 20      # cool!

For more details see: http://www.sellarafaeli.com/blog/ruby_monkeypatching_friendly_hashes

class Hash
  def [] key
    value = fetch key rescue
    case key
    when Symbol then "#{value}, as usual"
    when String then "#{value}, hooray!"
    else value end
  end
end