A while ago I had a walk among some of the plugins/gem available to add reflection on validations and/or force constraints on the database to be forced on Active Record models.
Since that moment I started thinking about a more declarative manner to manage and standardize the validations and to have the "validation rules" available in the views. I ended up writing something more generic than my initial idea, because I noticed soon I didn't need just the validation information about my model but even some other extra which were related to the class.
Today, I'm releasing Simple Descriptor v 0.1.0 (yes, it's a early release). It's a small piece of code that lets you add some chunk of informations to your class/models. The library doesn't depend from rails gems, so maybe it can be interesting even outside of the rails world.
The docs of the project can be found here
They're not complete, I may try to add some more in the future. I think what is provided now doesn't give enough ideas about how you can use the library. For the moment you may want to take a look at the tests to see some more sample of usage.
The rubyforge page of the project is
The library is distributed as a gem.
Any comment/contribution is very welcome.