validation groups

gistfile1.rb

# Hack to simulate validatable groups with Rails validations
# 
# Example:
# 
#  class MortgageApplication < ActiveRecord::Base
#    validation_group :underwriting
#    validates_presence_of :ssn
#    validates_presence_of :name, :if => :validating_for_underwriting?
#  end
#
#  MortgageApplication.new.valid? => false
#  MortgageApplication.new(:ssn => "something").valid? => true
#  MortgageApplication.new(:ssn => "something").valid_for_underwriting? => false
#  MortgageApplication.new(:ssn => "something", :name => "foo").valid_for_underwriting? => true

module ActiveRecord::Validations::ClassMethods
  def validation_group(name)
    ivar_name = :"@validating_for_#{name}"
    define_method(:"validating_for_#{name}?") do
      instance_variable_get(ivar_name)
    end

    define_method(:"valid_for_#{name}?") do
      instance_variable_set(ivar_name, true)
      result = valid?
      instance_variable_set(ivar_name, false)
      result
    end
  end
end