gistfile1.txt

# Monkey-patch for Ruby Datamapper 0.9.11 to add index support
# Load this after gems have been loaded
# Ho-Sheng Hsiao <twitter:hosheng>
#
# index :user_id
# index :user_id, :forum_id

# This monkeypatch does not have support for something like index :user_index, [ :user_id, :forum_id ] 

module DataMapper
  class PropertySet
    # FIXME: Kludge
    alias_method :indexes_without_outside_indexes, :indexes
    def indexes
      index_hash = indexes_without_outside_indexes
      repository_name = repository.name
      extra_indexes.each do |index, index_properties|
        # Probably a faster way to do this
        index_set = (index_hash[index.to_s] || [])
        index_properties.each { |property| index_set << property.field(repository_name) } 
        index_hash[index.to_s] = index_set
      end
      index_hash
    end

    def extra_indexes
      @indexes ||= []
    end

    def add_index(*index_properties)
      index_properties.flatten!
      index_name = index_properties.map { |p| p.to_s }.join('_').to_sym
      extra_indexes << [ index_name, index_properties.map { |p| property_for(p) }.compact ]
    end

  end

  # I have no idea how to do this the proper way. I'd like to do this like the is_ plugins
  module Model
    # Add indexes outside of property declaration
    #
    # Example:
    #   index :user_id
    #   index :user_id, forum_id
    #   index :forum_id, :user_id
    #
    # This automatically generates a index name, but does not support naming your own index
    def index(*index_properties)
      properties(repository.name).add_index(*index_properties)
    end
  end
end