Gluttonous

class Package < ActiveRecord::Base
  def <=>(other)
    versions = self.version.split(".").push self.rel
    other_versions = other.version.split(".").push other.rel

    versions.size.times do |n|
      if versions[n] =~ /[^\d]/ || other_versions[n] =~ /[^\d]/
        comparison = versions[n] <=> other_versions[n]
      else
        comparison = versions[n].to_i <=> other_versions[n].to_i
      end
      return comparison unless comparison.zero?
    end

    return 0 
  end
end

[Package.new(:version => "0.0.8a"), 
 Package.new(:version => "0.0.8c"), 
 Package.new(:version => "0.0.8b")].sort.map(&:version)
# => ["0.0.8a", "0.0.8b", "0.0.8c"] 

[Package.new(:version => "0.0.8"), 
 Package.new(:version => "0.0.10"), 
 Package.new(:version => "0.0.9")].sort.map(&:version)
# => ["0.0.8", "0.0.9", "0.0.10"]