John Hume

I don't think looking at the outer form should be necessary, I just included it to motivate my not wanting to treat the first argument as special. It seems to...

ActiveRecord's serialize will take as a second argument anything with `dump` and `load` methods, so that gives us a pretty good way to do what you're looking for. I just...

If you want to avoid the string issue I just mentioned, you could create a writer method [like constantize_attribute does](https://github.com/duelinmarkers/constantize_attribute/blob/master/lib/constantize_attribute.rb).