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 import System.Console.CmdArgs.Default ( Default(..) )
  11
  12 import qualified OptionalConfiguration as OC (
  13   OptionalConfiguration(..) )
  14 import Hosts ( Hosts(..) )
  15 import Lists ( Lists(..) )
  16
  17
  18 -- | The main configuration data type. This will be passed to most of
  19 --   the important functions once it has been created.
  20 --
  21 data Configuration =
  22   Configuration {
  23     hosts  :: Hosts,
  24     lists  :: Lists }
  25     deriving (Show)
  26
  27
  28 -- | A Configuration with all of its fields set to their default
  29 --   values.
  30 --
  31 instance Default Configuration where
  32   def = Configuration { hosts = def, lists = def }
  33
  34
  35 -- | Merge a 'Configuration' with an 'OptionalConfiguration'. This is
  36 --   more or less the Monoid instance for 'OptionalConfiguration', but
  37 --   since the two types are different, we have to repeat ourselves.
  38 --
  39 merge_optional :: Configuration
  40                -> OC.OptionalConfiguration
  41                -> Configuration
  42 merge_optional cfg opt_cfg =
  43   Configuration all_hosts all_lists
  44   where
  45     all_hosts =
  46       Hosts $ (get_hosts $ hosts cfg) ++ (get_hosts $ OC.hosts opt_cfg)
  47     all_lists =
  48       Lists $ (get_lists $ lists cfg) ++ (get_lists $ OC.lists opt_cfg)