Minor refactor

src/Handler/Users.hs

@@ -92,11 +92,9 @@ getUsersR = do
         ]
     , dbtFilter    = Map.fromList -- OverloadedLists does not work with the templates
         [ ( "user-search", FilterColumn $ \user criterion ->
-              let eFalse :: E.SqlExpr (E.Value Bool)
-                  eFalse = E.val False
-                  searchSql needle = E.castString (user E.^. UserDisplayName) `E.ilike` (E.%) E.++. E.val needle E.++. (E.%)
-              in  if Set.null criterion then E.val True else -- TODO: why is this condition not needed?
-                  Set.foldr (\needle acc -> acc E.||. searchSql needle) eFalse (criterion :: Set.Set Text)
+              -- let searchSql needle = E.castString (user E.^. UserDisplayName) `E.ilike` (E.%) E.++. E.val needle E.++. (E.%) in
+              if Set.null criterion then E.val True else -- TODO: why is this condition not needed?
+                  Set.foldr (\needle acc -> acc E.||. (user E.^. UserDisplayName) `eLike` needle) eFalse (criterion :: Set.Set Text)
           )
         , ( "matriculation", FilterColumn $ \user criterion -> if
               | Set.null criterion -> E.val True :: E.SqlExpr (E.Value Bool)
@@ -105,11 +103,11 @@ getUsersR = do
         , ( "school", FilterColumn $ \user criterion -> if
               | Set.null criterion -> E.val True :: E.SqlExpr (E.Value Bool)
               | otherwise          -> let schools = E.valList (Set.toList criterion) in
-                  ( E.exists $ E.from $ \ulectr -> do
+                    E.exists ( E.from $ \ulectr -> do
                       E.where_ $ ulectr E.^. UserLecturerUser    E.==. user E.^. UserId
                       E.where_ $ ulectr E.^. UserLecturerSchool `E.in_` schools
                   ) E.||.
-                  ( E.exists $ E.from $ \uadmin -> do
+                    E.exists ( E.from $ \uadmin -> do
                       E.where_ $ uadmin E.^. UserAdminUser       E.==. user E.^. UserId
                       E.where_ $ uadmin E.^. UserAdminSchool    `E.in_` schools
                   )

src/Utils/DB.hs

@@ -12,13 +12,24 @@ import qualified Database.Esqueleto as E
 
 -- ezero = E.val (0 :: Int64)
 
+-- | Often needed with this concrete type
+eTrue :: E.SqlExpr (E.Value Bool)
+eTrue  = E.val True
+
+-- | Often needed with this concrete type
+eFalse :: E.SqlExpr (E.Value Bool)
+eFalse = E.val False
+
+eLike :: (E.Esqueleto query expr backend, E.SqlString s2, E.SqlString s1) =>
+   expr (E.Value s2) -> s1 -> expr (E.Value Bool)
+eLike strExpr needle = E.castString strExpr `E.ilike` (E.%) E.++. E.val needle E.++. (E.%)
+
 emptyOrIn :: PersistField typ =>
   E.SqlExpr (E.Value typ) -> Set typ -> E.SqlExpr (E.Value Bool)
 emptyOrIn criterion testSet
   | Set.null testSet = E.val True
   | otherwise        = criterion `E.in_` E.valList (Set.toList testSet)
 
-
 entities2map :: PersistEntity record => [Entity record] -> Map (Key record) record
 entities2map = foldl' (\m entity -> Map.insert (entityKey entity) (entityVal entity) m) Map.empty