Introducing ActsAsMarkup: A Markdown, Textile, Wikitext, and RDoc Plugin for ActiveRecord
On a project I’ve been working on recently, I wanted to be able to enter in Markdown text to a field and convert it into HTML in a view. Having read about BlueCloth’s performance problems though, I didn’t want to use the built in markdown helper in ActionView.
So I decided to give RDiscount a try, but I wanted to have the value for the column stored as a RDiscount Markdown object in the model object. So I started by creating an acts_as_markdown class method that took a list of columns to be represented as markdown objects. Quickly, my fellow Vigeteers and I realized it would be useful for a bunch of other markup languages as well, along with other Markdown libraries.

Tyrant is a "meta" Rails application designed to run other Rails applications.
Recent Comments
I think that polymorphic_url(@commentable, :anchor => “comment_#{@comment.id}") should work. You can also refactor the “comment_#{@comment.id}” to a separated method, like dom_id, which returns the dom identifier of the comment.