Remove more boilerplate in TSN.XML.MLBBoxScore.

[dead/htsn-import.git] / src / Xml.hs

diff --git a/src/Xml.hs b/src/Xml.hs
index 5c846648a85d8a2f7b267db22b6b9b200dc67d78..ec409ac1b8f2eda9abda3312b020a347584c6cd0 100644 (file)
--- a/src/Xml.hs
+++ b/src/Xml.hs
@@ -4,10 +4,10 @@
 -- | General XML stuff.
 --
 module Xml (
+  Child(..),
   DtdName(..),
   FromXml(..),
   FromXmlFk(..),
-  FromXmlFkTeams(..),
   ToDb(..),
   parse_opts,
   pickle_unpickle,
@@ -38,9 +38,6 @@ import Text.XML.HXT.Core (
   yes )
 
 
--- Local imports.
-import TSN.Team ( Team(..) )
-
 
 -- | Common associated type shared by 'FromXml' and 'FromXmlFk'. This
 --   basically just forces the client to define the \"database
@@ -66,37 +63,29 @@ class (ToDb a) => FromXml a where
   from_xml :: a -> Db a
 
 
--- | Some database types cannot be constructed from the XML type
---   alone; they must be supplied a foreign key to a parent object
---   first. Members of this class can be converted from an XML
---   representation to a database representation in this manner.
+-- | A class for XML representations which are children of other
+--   elements. The foal is to associate a child XML element with its
+--   parent element's database type. This is required to construct the
+--   database analogue of @a@ in 'FromXmlFk'.
 --
-class (ToDb a) => FromXmlFk a where
+class Child a where
   -- | The type of our parent object, i.e. to the type to whom our
   --   foreign key will point.
   type Parent a :: *
 
+
+-- | Some database types cannot be constructed from the XML type
+--   alone; they must be supplied a foreign key to a parent object
+--   first. Members of this class can be converted from an XML
+--   representation to a database representation in this manner.
+--
+class (Child a, ToDb a) => FromXmlFk a where
   -- | The function that produces a @Db a@ out of a foreign key and an
   --   @a@. The parameter order makes it easier to map this function
   --   over a bunch of things.
   from_xml_fk :: DefaultKey (Parent a) -> a -> Db a
 
 
--- | 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 (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
-
 
 -- | Represents the DTD filename (\"SYSTEM\") part of the DOCTYPE
 --   definition.