1 files changed, 23 insertions, 0 deletions
diff --git a/server/src/Persistence/Frequency.hs b/server/src/Persistence/Frequency.hs
new file mode 100644
index 0000000..edaa844
--- /dev/null
+++ b/server/src/Persistence/Frequency.hs
@@ -0,0 +1,23 @@
+module Persistence.Frequency
+  ( FrequencyField(..)
+  ) where
+
+import qualified Data.Text                        as T
+import           Database.SQLite.Simple           (SQLData (SQLText))
+import           Database.SQLite.Simple.FromField (FromField (fromField),
+                                                   fieldData)
+import           Database.SQLite.Simple.Ok        (Ok (Errors, Ok))
+import           Database.SQLite.Simple.ToField   (ToField (toField))
+
+import           Common.Model                     (Frequency)
+
+newtype FrequencyField = FrequencyField Frequency
+
+instance FromField FrequencyField where
+  fromField field =
+    case fieldData field of
+      SQLText text -> Ok (FrequencyField (read (T.unpack text) :: Frequency))
+      _            -> Errors [error "SQLText field required for frequency"]
+
+instance ToField FrequencyField where
+  toField (FrequencyField f) = SQLText . T.pack . show $ f