Created
April 13, 2014 16:48
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Generic sort options in persistent
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{-# LANGUAGE QuasiQuotes, TemplateHaskell, TypeFamilies #-} | |
{-# LANGUAGE OverloadedStrings, GADTs #-} | |
import Data.Text (Text) | |
import Data.Time (UTCTime) | |
import Database.Persist | |
import Database.Persist.Sqlite (runSqlite, runMigration) | |
import Database.Persist.TH (mkPersist, persistLowerCase, sqlSettings) | |
mkPersist sqlSettings [persistLowerCase| | |
Model | |
name Text | |
created UTCTime | |
deriving Show | |
|] | |
getModelSorterOpt :: Text -> Text -> Maybe (SelectOpt Model) | |
getModelSorterOpt sortOrder sortField = | |
case sortField of | |
"id" -> Just $ sortOrder' ModelId | |
"name" -> Just $ sortOrder' ModelName | |
"created" -> Just $ sortOrder' ModelCreated | |
_ -> Nothing | |
where sortOrder' :: EntityField Model typ -> SelectOpt Model | |
sortOrder' = case sortOrder of | |
"Asc" -> Asc | |
"Desc" -> Desc |
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