Is it possible to do something like this:

hash[:key] = something

hash[:key] #=> 1

hash[:key] #=> 2

hash[:key] #=> 3

 
 
where I store something in a hash that automatically increments each time it is accessed
Apparently it is if you subclass Hash and store lambdas:

class CallHash < Hash

  def [](key)

    if fetch(key).respond_to?(:call)

      fetch(key).call

    else

      fetch(key)

    end

  rescue KeyError

    nil

  end

end

class CallHash < Hash

  def [](key)

    value = fetch key, nil

    return value.call if value.respond_to?(:call)

    value

  end

end