ActiveRecord without Rails

ar-test.rb

require 'rubygems'
require 'ar'
 
class DBSchema < AR::Schema 1.0
  def self.up
    create_table :users do |t|
      t.string :login
      t.string :password
    end
  end
 
  def self.down 
    drop_table :users
  end
end
 
class User < AR::Model
end
 
AR.db_connect( "test.yml", "test.log" )
 
User.new( :login => "Muriel", :password => "leiruM" ).save
User.new( :login => "Greg", :password => "gerG" ).save
 
User.all.each do |u|
  puts u.login
end
# => Muriel
# => Greg

ar.rb

begin
  require 'active_record'
rescue LoadError => e
  raise LoadError, "ActiveRecord ne doit pas être installé : #{e.message}"
end

class Object
  def meta_def(m,&b)
    (class<<self;self end).send(:define_method,m,&b)
  end
end

class Hash
  def keys_to_sym
    self.each do |k, v|
      self.delete(k)
      self[k.to_s.to_sym] = v
    end
  end
end

module AR
  Model = ActiveRecord::Base
  
  class SchemaInfo < Model
  end
  
  def self.Schema( n )
    @final = [n, @final.to_f].max
    m = (@migrations ||= [])
    Class.new(ActiveRecord::Migration) do
      meta_def(:version) { n }
      meta_def(:inherited) { |k| m << k }
    end
  end
  
  class << self
    def db_connect( dbfile, logfile )
      dbconfig = YAML::load(File.open(dbfile)).keys_to_sym
      version = dbconfig.delete(:schema_version) { |_| @final }
      
      ActiveRecord::Base.establish_connection(dbconfig)
      ActiveRecord::Base.logger = Logger.new(logfile)
      
      if @migrations
        unless SchemaInfo.table_exists?
          ActiveRecord::Schema.define do
            create_table SchemaInfo.table_name do |t|
              t.column :version, :float
            end
          end
        end
        si = SchemaInfo.find(:first) || SchemaInfo.new(:version => 0)
        @migrations.each do |k|
          k.migrate(:up) if si.version < k.version and k.version <= version
          k.migrate(:down) if si.version >= k.version and k.version > version
        end
        si.update_attributes(:version => version)
      end
    end
  end
end

test.yml

adapter: sqlite3
database: test.db
schema_version: 1.0