Rake tasks for a Magento extension using modman

Rakefile

require 'rake'

desc 'Displays current version'
task :version do
  puts "Current version is #{Version.new.to_s}"
end

namespace :version do
  desc "Bump version number"
  task :bump do
    version = Version.new
    puts "Bumped  version #{version.to_s} --> #{ENV['VER'] ? version.bump(ENV['VER']) : version.bump}"
  end

  desc "Set version number"
  task :set do
    version = Version.new
    puts "Changed version #{version.to_s} --> #{version.set(ENV['VER'])}"
  end
end

# Version object
class Version
  DEFAULT_CONFIG_FILE = "code/etc/config.xml"

  def initialize(config_file_path=DEFAULT_CONFIG_FILE)
    @config_file_path = config_file_path
    @config = File.open('code/etc/config.xml', 'rb').read

    @parts = Hash.new
    @parts[:major], @parts[:minor], @parts[:patch] = @config.match(/version>(.*)</)[1].split('.').collect(&:to_i)
  end

  def bump(ver= :patch)
    ver = ver.to_sym
    @parts[ver] = @parts[ver].to_i + 1
    if ver == :minor
      @parts[:patch] = 0
    elsif ver == :major
      @parts[:minor] = @parts[:patch] = 0
    end

    save
  end

  def set(new_version)
    @parts[:major], @parts[:minor], @parts[:patch] = new_version.split('.').collect(&:to_i)
    save
  end

  def to_s
    "#{major}.#{minor}.#{patch}"
  end

  def method_missing(method, *args)
    if [:major,:minor,:patch].include?(method)
      @parts[method]
    else
      super
    end
  end

  def save
    begin
      File.open(@config_file_path, 'w') do |f|
        f.write(@config.sub /<version>.*<.version>/, "<version>#{to_s}</version>")
      end
    rescue
      File.open(@config_file_path, 'w') {|f| f.write(@config)}
      raise
    end
    to_s
  end
end