Markus Werner wrote:
> access. IMHO The best would be a pre and a posthook. 

You can already have that kind of thing.
attr_ are actually simply another way to write the following methods:

def variable
   @variable
end

def variable=(value)
   @variable=value
end

If you write these methods yourself instead of using the 
attr_-construct, you can do whatever you want in the methods and it 
still looks the same to everyone who uses your class.

Greetings,
Henrik