refactor: Remove GHC.Show instances from Request.Types module

src/PostgREST/Config.hs

@@ -134,7 +134,7 @@ toText conf =
       ,("db-config",                 q . T.toLower . show . configDbConfig)
       ,("db-tx-end",                 q . showTxEnd)
       ,("db-uri",                    q . configDbUri)
-      ,("db-embed-default-join",     q . show . configDbEmbedDefaultJoin)
+      ,("db-embed-default-join",     q . innerJoin . configDbEmbedDefaultJoin)
       ,("db-use-legacy-gucs",            T.toLower . show . configDbUseLegacyGucs)
       ,("jwt-aud",                       toS . encode . maybe "" toJSON . configJwtAudience)
       ,("jwt-role-claim-key",        q . T.intercalate mempty . fmap show . configJwtRoleClaimKey)
@@ -168,6 +168,9 @@ toText conf =
         secret = fromMaybe mempty $ configJwtSecret c
     showSocketMode c = showOct (configServerUnixSocketMode c) mempty
 
+    innerJoin JTInner = "inner"
+    innerJoin JTLeft = "left"
+
 -- This class is needed for the polymorphism of overrideFromDbOrEnvironment
 -- because C.required and C.optional have different signatures
 class JustIfMaybe a b where

src/PostgREST/Query/SqlFragment.hs

@@ -52,6 +52,7 @@ import PostgREST.DbStructure.Identifiers (FieldName,
 import PostgREST.RangeQuery              (NonnegRange, allRange,
                                           rangeLimit, rangeOffset)
 import PostgREST.Request.Types           (Alias, Field, Filter (..),
+                                          OrderNulls(..), OrderDirection(..), LogicOperator(..),
                                           JoinCondition (..),
                                           JsonOperand (..),
                                           JsonOperation (..),
@@ -216,8 +217,15 @@ pgFmtOrderTerm :: QualifiedIdentifier -> OrderTerm -> SQL.Snippet
 pgFmtOrderTerm qi ot =
   pgFmtField qi (otTerm ot) <> " " <>
   SQL.sql (BS.unwords [
-    BS.pack $ maybe mempty show $ otDirection ot,
-    BS.pack $ maybe mempty show $ otNullOrder ot])
+    maybe mempty direction $ otDirection ot,
+    maybe mempty nullOrder $ otNullOrder ot])
+  where
+    direction OrderAsc  = "ASC"
+    direction OrderDesc = "DESC"
+
+    nullOrder OrderNullsFirst = "NULLS FIRST"
+    nullOrder OrderNullsLast  = "NULLS LAST"
+
 
 pgFmtFilter :: QualifiedIdentifier -> Filter -> SQL.Snippet
 pgFmtFilter table (Filter fld (OpExpr hasNot oper)) = notOp <> " " <> case oper of
@@ -255,8 +263,12 @@ pgFmtJoinCondition (JoinCondition (qi1, col1) (qi2, col2)) =
   SQL.sql $ pgFmtColumn qi1 col1 <> " = " <> pgFmtColumn qi2 col2
 
 pgFmtLogicTree :: QualifiedIdentifier -> LogicTree -> SQL.Snippet
-pgFmtLogicTree qi (Expr hasNot op forest) = SQL.sql notOp <> " (" <> intercalateSnippet (" " <> BS.pack (show op) <> " ") (pgFmtLogicTree qi <$> forest) <> ")"
-  where notOp =  if hasNot then "NOT" else mempty
+pgFmtLogicTree qi (Expr hasNot op forest) = SQL.sql notOp <> " (" <> intercalateSnippet (opSql op) (pgFmtLogicTree qi <$> forest) <> ")"
+  where
+    notOp =  if hasNot then "NOT" else mempty
+
+    opSql And = " AND "
+    opSql Or = " OR "
 pgFmtLogicTree qi (Stmnt flt) = pgFmtFilter qi flt
 
 pgFmtJsonPath :: JsonPath -> SQL.Snippet

src/PostgREST/Request/Types.hs

@@ -39,8 +39,6 @@ import qualified Data.Set             as S
 
 import Data.Tree (Tree (..))
 
-import qualified GHC.Show (show)
-
 import PostgREST.DbStructure.Identifiers  (FieldName,
                                            QualifiedIdentifier)
 import PostgREST.DbStructure.Proc         (ProcParam (..))
@@ -93,19 +91,11 @@ data OrderDirection
   | OrderDesc
   deriving (Eq)
 
-instance Show OrderDirection where
-  show OrderAsc  = "ASC"
-  show OrderDesc = "DESC"
-
 data OrderNulls
   = OrderNullsFirst
   | OrderNullsLast
   deriving (Eq)
 
-instance Show OrderNulls where
-  show OrderNullsFirst = "NULLS FIRST"
-  show OrderNullsLast  = "NULLS LAST"
-
 data MutateQuery
   = Insert
       { in_        :: QualifiedIdentifier
@@ -160,9 +150,6 @@ data JoinType
   = JTInner
   | JTLeft
   deriving Eq
-instance Show JoinType where
-  show JTInner = "inner"
-  show JTLeft  = "left"
 
 -- | Path of the embedded levels, e.g "clients.projects.name=eq.." gives Path
 -- ["clients", "projects"]
@@ -209,10 +196,6 @@ data LogicOperator
   | Or
   deriving Eq
 
-instance Show LogicOperator where
-  show And = "AND"
-  show Or  = "OR"
-
 data Filter = Filter
   { field  :: Field
   , opExpr :: OpExpr