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1. enumFromThenTo :: Enum a => a -> a -> a -> [a]

   hledger-web	Hledger.Web.Import

   Used in Haskell's translation of [n,n'..m] with [n,n'..m] = enumFromThenTo n n' m, a possible implementation being enumFromThenTo n n' m = worker (f x) (c x) n m, x = fromEnum n' - fromEnum n, c x = bool (>=) ((x 0)

   f n y
   | n > 0 = f (n - 1) (succ y)
   | n < 0 = f (n + 1) (pred y)
   | otherwise = y
   
   

   and

   worker s c v m
   | c v m = v : worker s c (s v) m
   | otherwise = []
   
   

   Examples

   • enumFromThenTo 4 2 -6 :: [Integer] =
     [4,2,0,-2,-4,-6]

   • enumFromThenTo 6 8 2 :: [Int] = []

2. enumFromTo :: Enum a => a -> a -> [a]

   hledger-web	Hledger.Web.Import

   Used in Haskell's translation of [n..m] with [n..m] = enumFromTo n m, a possible implementation being

   enumFromTo n m
   | n <= m = n : enumFromTo (succ n) m
   | otherwise = []
   
   

   Examples

   • enumFromTo 6 10 :: [Int] = [6,7,8,9,10]

   • enumFromTo 42 1 :: [Integer] = []

3. enumDeltaInteger :: forall (m :: Type -> Type) . Monad m => Integer -> Integer -> Stream m Integer

   leveldb-haskell	Data.Stream.Monadic

   Like fromList ([n,n+d..] :: [Integer]) but avoids allocating a list

4. enumFromToChar :: forall (m :: Type -> Type) . Monad m => Char -> Char -> Stream m Char

   leveldb-haskell	Data.Stream.Monadic

   Like fromList ([n..m] :: [Char]) but avoids allocating a list

5. enumFromToInt :: forall (m :: Type -> Type) . Monad m => Int -> Int -> Stream m Int

   leveldb-haskell	Data.Stream.Monadic

   Like fromList ([n..m] :: [Int]) but avoids allocating a list

6. enumDirective :: DirectiveConstraint a => TypeName -> a -> DirectiveUsages

   morpheus-graphql-server	Data.Morpheus.Server.Types

   No documentation available.

7. enumDirective' :: DirectiveConstraint a => Name -> a -> DirectiveUsages

   morpheus-graphql-server	Data.Morpheus.Server.Types

   No documentation available.

8. enumFromField :: EnumMapper sqlEnum haskellSum -> FromField sqlEnum haskellSum

   opaleye	Opaleye.Experimental.Enum

   No documentation available.

9. enumMapper :: String -> (String -> Maybe haskellSum) -> (haskellSum -> String) -> EnumMapper sqlEnum haskellSum

   opaleye	Opaleye.Experimental.Enum

   Create a mapping between a Postgres ENUM type and a Haskell type. Also works for DOMAIN types. For example, if you have the following ENUM

   CREATE TYPE public.mpaa_rating AS ENUM (
   'G',
   'PG',
   'PG-13',
   'R',
   'NC-17'
   );
   

   then you can define data types to represent the enum on the SQL side and Haskell side respectively

   data SqlRating
   data Rating = G | PG | PG13 | R | NC17 deriving Show
   

   and functions to map between them

   toSqlRatingString :: Rating -> String
   toSqlRatingString r = case r of
   G    -> "G"
   PG   -> "PG"
   PG13 -> "PG-13"
   R    -> "R"
   NC17 -> "NC-17"
   
   fromSqlRatingString :: String -> Maybe Rating
   fromSqlRatingString s = case s of
   "G"     -> Just G
   "PG"    -> Just PG
   "PG-13" -> Just PG13
   "R"     -> Just R
   "NC-17" -> Just NC17
   _       -> Nothing
   

   Then you can use the mappings as follows

   import qualified Opaleye as O
   import qualified Data.Profunctor.Product.Default as D
   
   sqlRatingMapper :: EnumMapper SqlRating Rating
   sqlRatingMapper = enumMapper "mpaa_rating" fromSqlRatingString toSqlRatingString
   
   instance O.DefaultFromField SqlRating Rating where
   defaultFromField = enumFromField sqlRatingMapper
   
   instance rating ~ Rating
   => D.Default (Inferrable O.FromField) SqlRating rating where
   def = inferrableDef
   
   instance D.Default O.ToFields Rating (O.Field SqlRating) where
   def = enumToFields sqlRatingMapper
   
   instance IsSqlType SqlRating where
   showSqlType = enumShowSqlType sqlRatingMapper
   

10. enumMapperWithSchema :: String -> String -> (String -> Maybe haskellSum) -> (haskellSum -> String) -> EnumMapper sqlEnum haskellSum

    opaleye	Opaleye.Experimental.Enum

    No documentation available.

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