X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FTSN%2FTeam.hs;h=2f58acf6de5817903e37643a194158bb0842ff02;hb=3a8d465bcc6f36b6e7601cf1902e575171aa7beb;hp=97e36475e59c14ea93c64a819e5b275b121bdd87;hpb=adfab819cdeb2774e811f68f4c7dda7668b1fa77;p=dead%2Fhtsn-import.git

diff --git a/src/TSN/Team.hs b/src/TSN/Team.hs
index 97e3647..2f58acf 100644
--- a/src/TSN/Team.hs
+++ b/src/TSN/Team.hs
@@ -13,18 +13,27 @@
 --   representation.
 --
 module TSN.Team (
+  HTeam(..),
+  FromXmlFkTeams(..),
   Team(..),
+  VTeam(..),
   -- * WARNING: these are private but exported to silence warnings
   TeamConstructor(..) )
 where
 
 -- System imports
 import Database.Groundhog () -- Required for some String instance
+import Database.Groundhog.Core ( PersistEntity(..) )
 import Database.Groundhog.TH (
   defaultCodegenConfig,
   groundhog,
   mkPersist )
 
+-- Local imports
+import Xml ( Child(..), Db(..) )
+
+
+-- * Team
 
 -- | The database representation of a team. The 'team_id' is a
 --   'String' field because some teams do in fact have ids like
@@ -43,6 +52,24 @@ data Team =
   deriving (Eq, Show)
 
 
+-- * VTeam / HTeam
+
+-- | A wrapper around 'Team' that lets us distinguish between home and
+--   away teams. See also 'HTeam'. \"V\" (visiting) was chosen instead
+--   of \"A\" (away) simply because \"vteam\" looks better than
+--   \"ateam\". This is purely for type-safety.
+--
+newtype VTeam = VTeam { vteam :: Team } deriving (Eq, Show)
+
+
+-- | A wrapper around 'Team' that lets us distinguish between home and
+--   away teams. See also 'VTeam'. This is purely for type-safety.
+--
+newtype HTeam = HTeam { hteam :: Team } deriving (Eq, Show)
+
+
+-- * Database stuff
+
 -- Generate the Groundhog code for 'Team'.
 mkPersist defaultCodegenConfig [groundhog|
 - entity: Team
@@ -54,3 +81,20 @@ mkPersist defaultCodegenConfig [groundhog|
           type: constraint
           fields: [team_id]
 |]
+
+
+
+-- | A further refinement of 'FromXmlFk'. These types need not only a
+--   foreign key to a parent in order to make the XML -> DB
+--   conversion, but also two foreign keys to away/home teams (as
+--   represented in "TSN.Team").
+--
+class (Child a, ToDb a) => FromXmlFkTeams a where
+  -- | The function that produces a @Db a@ out of a parent foreign
+  -- key, two team foreign keys, and an @a@. The parameter order makes
+  -- it easier to map this function over a bunch of things.
+  from_xml_fk_teams :: DefaultKey (Parent a)
+                    -> DefaultKey Team -- ^ The away team FK
+                    -> DefaultKey Team -- ^ The home team FK
+                    -> a
+                    -> Db a