dhh

class Ticket < ActiveRecord::Base
  belongs_to :grouper
  belongs_to :user

  validate :user_cant_be_blacklisted, on: :confirmation
  validate :user_cant_double_book, on: :confirmation

  validate :grouper_cant_be_full, on: :confirmation
  validate :grouper_cant_have_occurred, on: :confirmation

ryanb

My issues with Modules

In researching topics for RailsCasts I often read code in Rails and other gems. This is a great exercise to do. Not only will you pick up some coding tips, but it can help you better understand what makes code readable.

A common practice to organize code in gems is to divide it into modules. When this is done extensively I find it becomes very difficult to read. Before I explain further, a quick detour on instance_eval.

You can find instance_eval used in many DSLs: from routes to state machines. Here's an example from Thinking Sphinx.

class Article < ActiveRecord::Base