"Greedy" meta-property that makes out-of-model properties accessible

[ghost]

As an example for what I want I'll use the YAML adapter for working with configuration files.

Let's say I have a configuration file that's devided into different sections:

---
- name: section
  key: value
  foo: bar
- name: other_section
  herp: derp

The key-value pairs in each section are supposed to be more or less fluid. Though currently I'd need to specify each key in the model in order for DataMapper to read/write it.

I have some code in dm-types (greedy branch) and dm-yaml-adapter (greedy branch) that implements a kind of meta-property that reads and writes all properties that are not part of the defined model and makes them accessible as a Hash.

With these changes I'm able to define the following model:

class Config
  include DataMapper::Resource
  property :name, String, :key => true
  property :payload, DataMapper::Property::Greedy
end

The greedy property needs support from each used adapter, as the adapter needs to read and write the out-of-model properties to the greedy property.

What do you think about this? Are there other approaches to this or even an existing solution?

[ghost]

This is very similar to what Rails 3.2 does with ActiveRecord::Base.store