```ruby
require 'gir_ffi/builder_helper'
require 'gir_ffi/builder/type/base'
require 'gir_ffi/builder/type/callback'
require 'gir_ffi/builder/type/enum'
require 'gir_ffi/builder/type/union'
require 'gir_ffi/builder/type/object'
require 'gir_ffi/builder/type/struct'
require 'gir_ffi/builder/type/interface'

module GirFFI
  # Builds a class based on information found in the introspection
  # repository.
  module Builder
    module Type
      def self.build info
        case info.info_type
        when :callback
          Callback
        when :enum, :flags
          Enum
        when :union
          Union
        when :object
          Object
        when :struct
          Struct
        when :interface
          Interface
        end.new(info).build_class
      end
    end
  end
end
```

Replace case statement with a hash look-up for Type builder.
user
```ruby
require 'gir_ffi/builder_helper'
require 'gir_ffi/builder/type/base'
require 'gir_ffi/builder/type/callback'
require 'gir_ffi/builder/type/enum'
require 'gir_ffi/builder/type/union'
require 'gir_ffi/builder/type/object'
require 'gir_ffi/builder/type/struct'
require 'gir_ffi/builder/type/interface'

module GirFFI
  # Builds a class based on information found in the introspection
  # repository.
  module Builder
    module Type
      TYPE_MAP = {
        :callback => Callback,
        :enum => Enum,
        :flags => Enum,
        :interface => Interface,
        :object => Object,
        :struct => Struct,
        :union => Union
      }

      def self.build info
        TYPE_MAP[info.info_type].new(info).build_class
      end
    end
  end
end
```
assistant