New module: TSN.Location.

[dead/htsn-import.git] / src / TSN / Location.hs

diff --git a/src/TSN/Location.hs b/src/TSN/Location.hs
new file mode 100644 (file)
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+++ b/src/TSN/Location.hs
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+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE QuasiQuotes #-}
+{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TypeFamilies #-}
+
+-- | (At least) two different XML types have a notion of locations:
+--   "TSN.XML.News" and "TSN.XML.Scores". And in fact those two types
+--   agree on the city, state, and country -- at least for the
+--   database representation.
+--
+--   This module contains a data type for the common database
+--   representation.
+--
+module TSN.Location (
+  Location(..),
+  LocationConstructor(..) )
+where
+
+-- System imports
+import Database.Groundhog () -- Required for some String instance
+import Database.Groundhog.TH (
+  defaultCodegenConfig,
+  groundhog,
+  mkPersist )
+
+
+-- | Database representation of a location.
+--
+--   The country has always been present in the XML that we've
+--   seen. The city/state however have been observed missing in some
+--   cases. The Scores are better about always having a city/state,
+--   but in the interest of consolidation, we've made them optional so
+--   that they can be mushed together into this one type.
+--
+data Location =
+  Location {
+    city :: Maybe String,
+    state :: Maybe String,
+    country :: String }
+  deriving (Eq, Show)
+
+
+-- Generate the Groundhog code for 'Location'.
+mkPersist defaultCodegenConfig [groundhog|
+- entity: Location
+  dbName: locations
+  constructors:
+    - name: Location
+      uniques:
+        - name: unique_location
+          type: constraint
+          fields: [city, state, country]
+|]