harbl-cli/src/Configuration.hs

   1 -- | This module defines the 'Configuration' type, which is just a
   2 --   wrapper around all of the configuration options we accept on the
   3 --   command line.
   4 --
   5 module Configuration (
   6   Configuration(..),
   7   merge_optional )
   8 where
   9
  10 -- System imports.
  11 import System.Console.CmdArgs.Default ( Default(..) )
  12
  13 -- Harbl library imports.
  14 import Network.DNS.RBL.Weight ( Weight )
  15
  16 -- Local imports.
  17 import qualified OptionalConfiguration as OC (
  18   OptionalConfiguration(..),
  19   merge_maybe,
  20   merge_monoid )
  21 import Hosts ( Hosts(..) )
  22 import Lists ( Lists(..) )
  23
  24
  25 -- | The main configuration data type. This will be passed to most of
  26 --   the important functions once it has been created.
  27 --
  28 data Configuration =
  29   Configuration {
  30     hosts  :: Hosts,
  31     lists  :: Lists,
  32     threshold :: Weight }
  33     deriving (Show)
  34
  35
  36 -- | A Configuration with all of its fields set to their default
  37 --   values.
  38 --
  39 instance Default Configuration where
  40   def = Configuration { hosts = def,
  41                         lists = def,
  42                         threshold = def }
  43
  44
  45 -- | Merge a 'Configuration' with an 'OptionalConfiguration'. This is
  46 --   more or less the Monoid instance for 'OptionalConfiguration', but
  47 --   since the two types are different, we have to repeat ourselves.
  48 --
  49 merge_optional :: Configuration
  50                -> OC.OptionalConfiguration
  51                -> Configuration
  52 merge_optional cfg opt_cfg = Configuration hs ls t
  53   where
  54     hs = OC.merge_monoid (hosts cfg) (OC.hosts opt_cfg)
  55     ls = OC.merge_monoid (lists cfg) (OC.lists opt_cfg)
  56     t  = OC.merge_maybe (threshold cfg) (OC.threshold opt_cfg)