From: Tony Arcieri <tony@...>
Date: 2009-04-14T03:50:31+09:00
Subject: Re: Ruby vs. Groovy: your perspective

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On Mon, Apr 13, 2009 at 5:35 AM, Diego Virasoro <Diego.Virasoro@gmail.com>wrote:

> Still I've heard a bit about Groovy and it kind of seems like the Java
> answer to Ruby (even the names are kind of similar). So I was
> wondering if that kind of "first citizen" status will eventually make
> it take over Ruby as a dynamic language (assuming that indeed that the
> Groovy language offers everything Ruby does).
>

One of the most powerful Ruby idioms I know of requires features Groovy
doesn't have.  I'm talking about creating a small declarative "DSL" you call
from a class body to metaprogram methods, such as with ActiveRecord
associations, e.g.:

 class Foo < ActiveRecord::Base
   has_many :bars
   has_many :bazzes, :through => :quuxes, :order => "created_at DESC"
 end

This allows for instances of Foo to potentially respond to many different
methods based on the association names (e.g. you can call afoo.bars to get a
collection of associated bars)

Groovy does not allow code in class bodies (at least last I checked), and I
believe Grails tries to work around this with static properties, which can't
provide the full expressive power of a DSL.

I've heard generally bad things about Groovy's approach to metaclasses and
metaprogramming in general, but as I haven't used Groovy I can't really
comment in that regard.

-- 
Tony Arcieri

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