Metaprogramming in Grails

Groovy is a swing-and-a-miss. It will go down like OS/2 did. People will say "man that Groovy language was so good, I don't know why it didn't catch on." Here's an example of why it is a fail.

I was reading this article on developerWorks about GORM, the OR framework in Grails. Like everything else in Grails, it is "inspired" by Ruby on Rails. In this case GORM was inspired by ActiveRecord. In GORM here is an association:

class Airline {
 static hasMany = [trip:Trip]

 String name
 String url
 String frequentFlyer
 String notes
}

Compare this to the same thing in Rails

class Airline < ActiveRecord::Base
 has_many :trips
end

Forget the explicit listing of fields for a minute, concentrate on the has-many notation used by both frameworks. In Grails, you have a static field that has a special name. In ActiveRecord you use a meta-API or macro (or whatever you want to call it) to dynamically add methods to each instance of Airline. Grails accomplishes the same thing, but it is much more of a hack. You just happen to have a static field that has a special name.

It just feels like "wow that feature is cool, we can't do it the same way ... but we can hack something together that is pretty close!" Just seems like Groovy comes up short.