Semantic Attributes (validation, machine/human formatting)

I’ve never taken the time to package/release/announce this plugin of mine, have I? Forgive me. The time has come.

I introduce to you Semantic Attributes!

From the README:

The method-chained validation routine built into ActiveRecord must
die! It’s time for an object-oriented approach to attribute
validations. The Semantic Attributes plugin provides this approach by
letting you attach predicates to your attributes with a tasty DSL.
These predicates package up some really sweet behavior, where
validations are really only the beginning. I’ve also discovered that it
can be really useful to use these predicates to convert between human
and machine formats: for example, with the phone number predicate you
can let your users enter phone numbers with whatever formatting they
want, always save the values to the database as numeric strings, and
then present the values back to the user with standard formatting.

I’ve
also found other nifty uses for object-oriented predicates that package
up validation. For example, it becomes easy to run a quick validation
check on a field with a sample value and report true/false. This is
exactly what the expected_error_for(:field, value)>
method does, and it lets you build a validation routine that listens to
form data as it’s being typed and report problems without duplicating
your validation code client-side. In a similar vein, the _valid? attribute suffix lets you do single-attribute validation on a record anytime you want.

For more, see:

and of course:

-Lance

p.s. this is completely compatible with ActiveRecord validations … you can use 'em both if you want