{-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE RecordWildCards #-} {-# LANGUAGE CPP #-} {-# LANGUAGE OverloadedStrings #-} {-# LANGUAGE RankNTypes #-} {-# LANGUAGE TupleSections #-} {-# LANGUAGE FlexibleContexts, FlexibleInstances, MultiParamTypeClasses #-} {-# LANGUAGE UndecidableInstances #-} {-# OPTIONS_GHC -fno-warn-orphans -fno-warn-missing-fields #-} #if !MIN_VERSION_base(4,8,0) -- overlapping instances is for automatic lifting -- while avoiding an orphan of Lift for Text {-# LANGUAGE OverlappingInstances #-} #endif -- | This module provides utilities for creating backends. Regular users do not -- need to use this module. module Database.Persist.TH ( -- * Parse entity defs persistWith , persistUpperCase , persistLowerCase , persistFileWith , persistManyFileWith -- * Turn @EntityDef@s into types , mkPersist , MkPersistSettings , mpsBackend , mpsGeneric , mpsPrefixFields , mpsEntityJSON , mpsGenerateLenses , EntityJSON(..) , mkPersistSettings , sqlSettings , sqlOnlySettings -- * Various other TH functions , mkMigrate , mkSave , mkDeleteCascade , share , derivePersistField , derivePersistFieldJSON , persistFieldFromEntity -- * Internal , packPTH , lensPTH , parseReferences ) where import Prelude hiding ((++), take, concat, splitAt, exp) import Database.Persist import Database.Persist.Sql (Migration, migrate, SqlBackend, PersistFieldSql) import Database.Persist.Quasi import Language.Haskell.TH.Lib ( #if MIN_VERSION_template_haskell(2,11,0) conT, #endif varE) import Language.Haskell.TH.Quote import Language.Haskell.TH.Syntax import Data.Char (toLower, toUpper) import Control.Monad (forM, (<=<), mzero) import qualified System.IO as SIO import Data.Text (pack, Text, append, unpack, concat, uncons, cons, stripPrefix, stripSuffix) import qualified Data.Text as T import Data.Text.Encoding (decodeUtf8) import qualified Data.Text.IO as TIO import Data.Int (Int64) import Data.List (foldl') import Data.Maybe (isJust, listToMaybe, mapMaybe, fromMaybe) import Data.Monoid (mappend, mconcat) import Text.Read (readPrec, lexP, step, prec, parens, Lexeme(Ident)) import qualified Data.Map as M import qualified Data.HashMap.Strict as HM import Data.Aeson.Compat ( ToJSON (toJSON), FromJSON (parseJSON), (.=), object , Value (Object), (.:), (.:?) , eitherDecodeStrict' ) import Control.Applicative as A (pure, (<$>), (<*>)) import Database.Persist.Sql (sqlType) import Data.Proxy (Proxy (Proxy)) import Web.PathPieces (PathPiece(..)) import Web.HttpApiData (ToHttpApiData(..), FromHttpApiData(..)) import GHC.Generics (Generic) import qualified Data.Text.Encoding as TE -- | This special-cases "type_" and strips out its underscore. When -- used for JSON serialization and deserialization, it works around -- unHaskellNameForJSON :: HaskellName -> Text unHaskellNameForJSON = fixTypeUnderscore . unHaskellName where fixTypeUnderscore "type" = "type_" fixTypeUnderscore name = name -- | Converts a quasi-quoted syntax into a list of entity definitions, to be -- used as input to the template haskell generation code (mkPersist). persistWith :: PersistSettings -> QuasiQuoter persistWith ps = QuasiQuoter { quoteExp = parseReferences ps . pack } -- | Apply 'persistWith' to 'upperCaseSettings'. persistUpperCase :: QuasiQuoter persistUpperCase = persistWith upperCaseSettings -- | Apply 'persistWith' to 'lowerCaseSettings'. persistLowerCase :: QuasiQuoter persistLowerCase = persistWith lowerCaseSettings -- | Same as 'persistWith', but uses an external file instead of a -- quasiquotation. persistFileWith :: PersistSettings -> FilePath -> Q Exp persistFileWith ps fp = persistManyFileWith ps [fp] -- | Same as 'persistFileWith', but uses several external files instead of -- one. Splitting your Persistent definitions into multiple modules can -- potentially dramatically speed up compile times. -- -- ==== __Examples__ -- -- Split your Persistent definitions into multiple files (@models1@, @models2@), -- then create a new module for each new file and run 'mkPersist' there: -- -- @ -- -- Model1.hs -- 'share' -- ['mkPersist' 'sqlSettings'] -- $('persistFileWith' 'lowerCaseSettings' "models1") -- @ -- @ -- -- Model2.hs -- 'share' -- ['mkPersist' 'sqlSettings'] -- $('persistFileWith' 'lowerCaseSettings' "models2") -- @ -- -- Use 'persistManyFileWith' to create your migrations: -- -- @ -- -- Migrate.hs -- 'share' -- ['mkMigrate' "migrateAll"] -- $('persistManyFileWith' 'lowerCaseSettings' ["models1","models2"]) -- @ -- -- Tip: To get the same import behavior as if you were declaring all your models in -- one file, import your new files @as Name@ into another file, then export @module Name@. -- -- This approach may be used in the future to reduce memory usage during compilation, -- but so far we've only seen mild reductions. -- -- See and -- for more details. -- -- @since 2.5.4 persistManyFileWith :: PersistSettings -> [FilePath] -> Q Exp persistManyFileWith ps fps = do #ifdef GHC_7_4 mapM_ qAddDependentFile fps #endif ss <- mapM getS fps let s = T.intercalate "\n" ss -- be tolerant of the user forgetting to put a line-break at EOF. parseReferences ps s where getS fp = do h <- qRunIO $ SIO.openFile fp SIO.ReadMode qRunIO $ SIO.hSetEncoding h SIO.utf8_bom s <- qRunIO $ TIO.hGetContents h return s -- calls parse to Quasi.parse individual entities in isolation -- afterwards, sets references to other entities -- | @since 2.5.3 parseReferences :: PersistSettings -> Text -> Q Exp parseReferences ps s = lift $ map (mkEntityDefSqlTypeExp embedEntityMap entMap) noCycleEnts where entMap = M.fromList $ map (\ent -> (entityHaskell ent, ent)) noCycleEnts noCycleEnts = map breakCycleEnt entsWithEmbeds -- every EntityDef could reference each-other (as an EmbedRef) -- let Haskell tie the knot embedEntityMap = M.fromList $ map (\ent -> (entityHaskell ent, toEmbedEntityDef ent)) entsWithEmbeds entsWithEmbeds = map setEmbedEntity rawEnts setEmbedEntity ent = ent { entityFields = map (setEmbedField (entityHaskell ent) embedEntityMap) $ entityFields ent } rawEnts = parse ps s -- self references are already broken -- look at every emFieldEmbed to see if it refers to an already seen HaskellName -- so start with entityHaskell ent and accumulate embeddedHaskell em breakCycleEnt entDef = let entName = entityHaskell entDef in entDef { entityFields = map (breakCycleField entName) $ entityFields entDef } breakCycleField entName f@(FieldDef { fieldReference = EmbedRef em }) = f { fieldReference = EmbedRef $ breakCycleEmbed [entName] em } breakCycleField _ f = f breakCycleEmbed ancestors em = em { embeddedFields = map (breakCycleEmField $ emName : ancestors) (embeddedFields em) } where emName = embeddedHaskell em breakCycleEmField ancestors emf = case embeddedHaskell <$> membed of Nothing -> emf Just embName -> if embName `elem` ancestors then emf { emFieldEmbed = Nothing, emFieldCycle = Just embName } else emf { emFieldEmbed = breakCycleEmbed ancestors <$> membed } where membed = emFieldEmbed emf stripId :: FieldType -> Maybe Text stripId (FTTypeCon Nothing t) = stripSuffix "Id" t stripId _ = Nothing foreignReference :: FieldDef -> Maybe HaskellName foreignReference field = case fieldReference field of ForeignRef ref _ -> Just ref _ -> Nothing -- fieldSqlType at parse time can be an Exp -- This helps delay setting fieldSqlType until lift time data EntityDefSqlTypeExp = EntityDefSqlTypeExp EntityDef SqlTypeExp [SqlTypeExp] deriving Show data SqlTypeExp = SqlTypeExp FieldType | SqlType' SqlType deriving Show instance Lift SqlTypeExp where lift (SqlType' t) = lift t lift (SqlTypeExp ftype) = return st where typ = ftToType ftype mtyp = (ConT ''Proxy `AppT` typ) typedNothing = SigE (ConE 'Proxy) mtyp st = VarE 'sqlType `AppE` typedNothing data FieldsSqlTypeExp = FieldsSqlTypeExp [FieldDef] [SqlTypeExp] instance Lift FieldsSqlTypeExp where lift (FieldsSqlTypeExp fields sqlTypeExps) = lift $ zipWith FieldSqlTypeExp fields sqlTypeExps data FieldSqlTypeExp = FieldSqlTypeExp FieldDef SqlTypeExp instance Lift FieldSqlTypeExp where lift (FieldSqlTypeExp (FieldDef{..}) sqlTypeExp) = [|FieldDef fieldHaskell fieldDB fieldType $(lift sqlTypeExp) fieldAttrs fieldStrict fieldReference|] instance Lift EntityDefSqlTypeExp where lift (EntityDefSqlTypeExp ent sqlTypeExp sqlTypeExps) = [|ent { entityFields = $(lift $ FieldsSqlTypeExp (entityFields ent) sqlTypeExps) , entityId = $(lift $ FieldSqlTypeExp (entityId ent) sqlTypeExp) } |] instance Lift ReferenceDef where lift NoReference = [|NoReference|] lift (ForeignRef name ft) = [|ForeignRef name ft|] lift (EmbedRef em) = [|EmbedRef em|] lift (CompositeRef cdef) = [|CompositeRef cdef|] lift (SelfReference) = [|SelfReference|] instance Lift EmbedEntityDef where lift (EmbedEntityDef name fields) = [|EmbedEntityDef name fields|] instance Lift EmbedFieldDef where lift (EmbedFieldDef name em cyc) = [|EmbedFieldDef name em cyc|] type EmbedEntityMap = M.Map HaskellName EmbedEntityDef type EntityMap = M.Map HaskellName EntityDef data FTTypeConDescr = FTKeyCon deriving Show mEmbedded :: EmbedEntityMap -> FieldType -> Either (Maybe FTTypeConDescr) EmbedEntityDef mEmbedded _ (FTTypeCon Just{} _) = Left Nothing mEmbedded ents (FTTypeCon Nothing n) = let name = HaskellName n in maybe (Left Nothing) Right $ M.lookup name ents mEmbedded ents (FTList x) = mEmbedded ents x mEmbedded ents (FTApp x y) = -- Key converts an Record to a RecordId -- special casing this is obviously a hack -- This problem may not be solvable with the current QuasiQuoted approach though if x == FTTypeCon Nothing "Key" then Left $ Just FTKeyCon else mEmbedded ents y setEmbedField :: HaskellName -> EmbedEntityMap -> FieldDef -> FieldDef setEmbedField entName allEntities field = field { fieldReference = case fieldReference field of NoReference -> case mEmbedded allEntities (fieldType field) of Left _ -> case stripId $ fieldType field of Nothing -> NoReference Just name -> case M.lookup (HaskellName name) allEntities of Nothing -> NoReference Just _ -> ForeignRef (HaskellName name) -- This can get corrected in mkEntityDefSqlTypeExp (FTTypeCon (Just "Data.Int") "Int64") Right em -> if embeddedHaskell em /= entName then EmbedRef em else if maybeNullable field then SelfReference else case fieldType field of FTList _ -> SelfReference _ -> error $ unpack $ unHaskellName entName `Data.Monoid.mappend` ": a self reference must be a Maybe" existing@_ -> existing } mkEntityDefSqlTypeExp :: EmbedEntityMap -> EntityMap -> EntityDef -> EntityDefSqlTypeExp mkEntityDefSqlTypeExp emEntities entMap ent = EntityDefSqlTypeExp ent (getSqlType $ entityId ent) $ (map getSqlType $ entityFields ent) where getSqlType field = maybe (defaultSqlTypeExp field) (SqlType' . SqlOther) (listToMaybe $ mapMaybe (stripPrefix "sqltype=") $ fieldAttrs field) -- In the case of embedding, there won't be any datatype created yet. -- We just use SqlString, as the data will be serialized to JSON. defaultSqlTypeExp field = case mEmbedded emEntities ftype of Right _ -> SqlType' SqlString Left (Just FTKeyCon) -> SqlType' SqlString Left Nothing -> case fieldReference field of ForeignRef refName ft -> case M.lookup refName entMap of Nothing -> SqlTypeExp ft -- A ForeignRef is blindly set to an Int64 in setEmbedField -- correct that now Just ent' -> case entityPrimary ent' of Nothing -> SqlTypeExp ft Just pdef -> case compositeFields pdef of [] -> error "mkEntityDefSqlTypeExp: no composite fields" [x] -> SqlTypeExp $ fieldType x _ -> SqlType' $ SqlOther "Composite Reference" CompositeRef _ -> SqlType' $ SqlOther "Composite Reference" _ -> case ftype of -- In the case of lists, we always serialize to a string -- value (via JSON). -- -- Normally, this would be determined automatically by -- SqlTypeExp. However, there's one corner case: if there's -- a list of entity IDs, the datatype for the ID has not -- yet been created, so the compiler will fail. This extra -- clause works around this limitation. FTList _ -> SqlType' SqlString _ -> SqlTypeExp ftype where ftype = fieldType field -- | Create data types and appropriate 'PersistEntity' instances for the given -- 'EntityDef's. Works well with the persist quasi-quoter. mkPersist :: MkPersistSettings -> [EntityDef] -> Q [Dec] mkPersist mps ents' = do x <- fmap Data.Monoid.mconcat $ mapM (persistFieldFromEntity mps) ents y <- fmap mconcat $ mapM (mkEntity entMap mps) ents z <- fmap mconcat $ mapM (mkJSON mps) ents return $ mconcat [x, y, z] where ents = map fixEntityDef ents' entMap = M.fromList $ map (\ent -> (entityHaskell ent, ent)) ents -- | Implement special preprocessing on EntityDef as necessary for 'mkPersist'. -- For example, strip out any fields marked as MigrationOnly. fixEntityDef :: EntityDef -> EntityDef fixEntityDef ed = ed { entityFields = filter keepField $ entityFields ed } where keepField fd = "MigrationOnly" `notElem` fieldAttrs fd && "SafeToRemove" `notElem` fieldAttrs fd -- | Settings to be passed to the 'mkPersist' function. data MkPersistSettings = MkPersistSettings { mpsBackend :: Type -- ^ Which database backend we\'re using. -- -- When generating data types, each type is given a generic version- which -- works with any backend- and a type synonym for the commonly used -- backend. This is where you specify that commonly used backend. , mpsGeneric :: Bool -- ^ Create generic types that can be used with multiple backends. Good for -- reusable code, but makes error messages harder to understand. Default: -- False. , mpsPrefixFields :: Bool -- ^ Prefix field names with the model name. Default: True. , mpsEntityJSON :: Maybe EntityJSON -- ^ Generate @ToJSON@/@FromJSON@ instances for each model types. If it's -- @Nothing@, no instances will be generated. Default: -- -- @ -- Just EntityJSON -- { entityToJSON = 'keyValueEntityToJSON -- , entityFromJSON = 'keyValueEntityFromJSON -- } -- @ , mpsGenerateLenses :: !Bool -- ^ Instead of generating normal field accessors, generator lens-style accessors. -- -- Default: False -- -- @since 1.3.1 } data EntityJSON = EntityJSON { entityToJSON :: Name -- ^ Name of the @toJSON@ implementation for @Entity a@. , entityFromJSON :: Name -- ^ Name of the @fromJSON@ implementation for @Entity a@. } -- | Create an @MkPersistSettings@ with default values. mkPersistSettings :: Type -- ^ Value for 'mpsBackend' -> MkPersistSettings mkPersistSettings t = MkPersistSettings { mpsBackend = t , mpsGeneric = False , mpsPrefixFields = True , mpsEntityJSON = Just EntityJSON { entityToJSON = 'entityIdToJSON , entityFromJSON = 'entityIdFromJSON } , mpsGenerateLenses = False } -- | Use the 'SqlPersist' backend. sqlSettings :: MkPersistSettings sqlSettings = mkPersistSettings $ ConT ''SqlBackend -- | Same as 'sqlSettings'. -- -- @since 1.1.1 sqlOnlySettings :: MkPersistSettings sqlOnlySettings = sqlSettings {-# DEPRECATED sqlOnlySettings "use sqlSettings" #-} recNameNoUnderscore :: MkPersistSettings -> HaskellName -> HaskellName -> Text recNameNoUnderscore mps dt f | mpsPrefixFields mps = lowerFirst (unHaskellName dt) ++ upperFirst ft | otherwise = lowerFirst ft where ft = unHaskellName f recName :: MkPersistSettings -> HaskellName -> HaskellName -> Text recName mps dt f = addUnderscore $ recNameNoUnderscore mps dt f where addUnderscore | mpsGenerateLenses mps = ("_" ++) | otherwise = id lowerFirst :: Text -> Text lowerFirst t = case uncons t of Just (a, b) -> cons (toLower a) b Nothing -> t upperFirst :: Text -> Text upperFirst t = case uncons t of Just (a, b) -> cons (toUpper a) b Nothing -> t dataTypeDec :: MkPersistSettings -> EntityDef -> Q Dec dataTypeDec mps t = do let names = map (mkName . unpack) $ entityDerives t #if MIN_VERSION_template_haskell(2,12,0) DataD [] nameFinal paramsFinal Nothing constrs <$> fmap (pure . DerivClause Nothing) (mapM conT names) #elif MIN_VERSION_template_haskell(2,11,0) DataD [] nameFinal paramsFinal Nothing constrs <$> mapM conT names #else return $ DataD [] nameFinal paramsFinal constrs names #endif where mkCol x fd@FieldDef {..} = (mkName $ unpack $ recName mps x fieldHaskell, if fieldStrict then isStrict else notStrict, maybeIdType mps fd Nothing Nothing ) (nameFinal, paramsFinal) | mpsGeneric mps = (nameG, [PlainTV backend]) | otherwise = (name, []) nameG = mkName $ unpack $ unHaskellName (entityHaskell t) ++ "Generic" name = mkName $ unpack $ unHaskellName $ entityHaskell t cols = map (mkCol $ entityHaskell t) $ entityFields t backend = backendName constrs | entitySum t = map sumCon $ entityFields t | otherwise = [RecC name cols] sumCon fd = NormalC (sumConstrName mps t fd) [(notStrict, maybeIdType mps fd Nothing Nothing)] sumConstrName :: MkPersistSettings -> EntityDef -> FieldDef -> Name sumConstrName mps t FieldDef {..} = mkName $ unpack $ concat [ if mpsPrefixFields mps then unHaskellName $ entityHaskell t else "" , upperFirst $ unHaskellName fieldHaskell , "Sum" ] uniqueTypeDec :: MkPersistSettings -> EntityDef -> Dec uniqueTypeDec mps t = DataInstD [] ''Unique [genericDataType mps (entityHaskell t) backendT] #if MIN_VERSION_template_haskell(2,11,0) Nothing #endif (map (mkUnique mps t) $ entityUniques t) [] mkUnique :: MkPersistSettings -> EntityDef -> UniqueDef -> Con mkUnique mps t (UniqueDef (HaskellName constr) _ fields attrs) = NormalC (mkName $ unpack constr) types where types = map (go . flip lookup3 (entityFields t)) $ map (unHaskellName . fst) fields force = "!force" `elem` attrs go :: (FieldDef, IsNullable) -> (Strict, Type) go (_, Nullable _) | not force = error nullErrMsg go (fd, y) = (notStrict, maybeIdType mps fd Nothing (Just y)) lookup3 :: Text -> [FieldDef] -> (FieldDef, IsNullable) lookup3 s [] = error $ unpack $ "Column not found: " ++ s ++ " in unique " ++ constr lookup3 x (fd@FieldDef {..}:rest) | x == unHaskellName fieldHaskell = (fd, nullable fieldAttrs) | otherwise = lookup3 x rest nullErrMsg = mconcat [ "Error: By default we disallow NULLables in an uniqueness " , "constraint. The semantics of how NULL interacts with those " , "constraints is non-trivial: two NULL values are not " , "considered equal for the purposes of an uniqueness " , "constraint. If you understand this feature, it is possible " , "to use it your advantage. *** Use a \"!force\" attribute " , "on the end of the line that defines your uniqueness " , "constraint in order to disable this check. ***" ] maybeIdType :: MkPersistSettings -> FieldDef -> Maybe Name -- ^ backend -> Maybe IsNullable -> Type maybeIdType mps fd mbackend mnull = maybeTyp mayNullable idtyp where mayNullable = case mnull of (Just (Nullable ByMaybeAttr)) -> True _ -> maybeNullable fd idtyp = idType mps fd mbackend backendDataType :: MkPersistSettings -> Type backendDataType mps | mpsGeneric mps = backendT | otherwise = mpsBackend mps genericDataType :: MkPersistSettings -> HaskellName -- ^ entity name -> Type -- ^ backend -> Type genericDataType mps (HaskellName typ') backend | mpsGeneric mps = ConT (mkName $ unpack $ typ' ++ "Generic") `AppT` backend | otherwise = ConT $ mkName $ unpack typ' idType :: MkPersistSettings -> FieldDef -> Maybe Name -> Type idType mps fd mbackend = case foreignReference fd of Just typ -> ConT ''Key `AppT` genericDataType mps typ (VarT $ fromMaybe backendName mbackend) Nothing -> ftToType $ fieldType fd degen :: [Clause] -> [Clause] degen [] = let err = VarE 'error `AppE` LitE (StringL "Degenerate case, should never happen") in [normalClause [WildP] err] degen x = x mkToPersistFields :: MkPersistSettings -> String -> EntityDef -> Q Dec mkToPersistFields mps constr ed@EntityDef { entitySum = isSum, entityFields = fields } = do clauses <- if isSum then sequence $ zipWith goSum fields [1..] else fmap return go return $ FunD 'toPersistFields clauses where go :: Q Clause go = do xs <- sequence $ replicate fieldCount $ newName "x" let pat = ConP (mkName constr) $ map VarP xs sp <- [|SomePersistField|] let bod = ListE $ map (AppE sp . VarE) xs return $ normalClause [pat] bod fieldCount = length fields goSum :: FieldDef -> Int -> Q Clause goSum fd idx = do let name = sumConstrName mps ed fd enull <- [|SomePersistField PersistNull|] let beforeCount = idx - 1 afterCount = fieldCount - idx before = replicate beforeCount enull after = replicate afterCount enull x <- newName "x" sp <- [|SomePersistField|] let body = ListE $ mconcat [ before , [sp `AppE` VarE x] , after ] return $ normalClause [ConP name [VarP x]] body mkToFieldNames :: [UniqueDef] -> Q Dec mkToFieldNames pairs = do pairs' <- mapM go pairs return $ FunD 'persistUniqueToFieldNames $ degen pairs' where go (UniqueDef constr _ names _) = do names' <- lift names return $ normalClause [RecP (mkName $ unpack $ unHaskellName constr) []] names' mkUniqueToValues :: [UniqueDef] -> Q Dec mkUniqueToValues pairs = do pairs' <- mapM go pairs return $ FunD 'persistUniqueToValues $ degen pairs' where go :: UniqueDef -> Q Clause go (UniqueDef constr _ names _) = do xs <- mapM (const $ newName "x") names let pat = ConP (mkName $ unpack $ unHaskellName constr) $ map VarP xs tpv <- [|toPersistValue|] let bod = ListE $ map (AppE tpv . VarE) xs return $ normalClause [pat] bod isNotNull :: PersistValue -> Bool isNotNull PersistNull = False isNotNull _ = True mapLeft :: (a -> c) -> Either a b -> Either c b mapLeft _ (Right r) = Right r mapLeft f (Left l) = Left (f l) fieldError :: Text -> Text -> Text fieldError fieldName err = "Couldn't parse field `" `mappend` fieldName `mappend` "` from database results: " `mappend` err mkFromPersistValues :: MkPersistSettings -> EntityDef -> Q [Clause] mkFromPersistValues _ t@(EntityDef { entitySum = False }) = fromValues t "fromPersistValues" entE $ entityFields t where entE = ConE $ mkName $ unpack entName entName = unHaskellName $ entityHaskell t mkFromPersistValues mps t@(EntityDef { entitySum = True }) = do nothing <- [|Left ("Invalid fromPersistValues input: sum type with all nulls. Entity: " `mappend` entName)|] clauses <- mkClauses [] $ entityFields t return $ clauses `mappend` [normalClause [WildP] nothing] where entName = unHaskellName $ entityHaskell t mkClauses _ [] = return [] mkClauses before (field:after) = do x <- newName "x" let null' = ConP 'PersistNull [] pat = ListP $ mconcat [ map (const null') before , [VarP x] , map (const null') after ] constr = ConE $ sumConstrName mps t field fs <- [|fromPersistValue $(return $ VarE x)|] let guard' = NormalG $ VarE 'isNotNull `AppE` VarE x let clause = Clause [pat] (GuardedB [(guard', InfixE (Just constr) fmapE (Just fs))]) [] clauses <- mkClauses (field : before) after return $ clause : clauses type Lens s t a b = forall f. Functor f => (a -> f b) -> s -> f t lensPTH :: (s -> a) -> (s -> b -> t) -> Lens s t a b lensPTH sa sbt afb s = fmap (sbt s) (afb $ sa s) fmapE :: Exp fmapE = VarE 'fmap mkLensClauses :: MkPersistSettings -> EntityDef -> Q [Clause] mkLensClauses mps t = do lens' <- [|lensPTH|] getId <- [|entityKey|] setId <- [|\(Entity _ value) key -> Entity key value|] getVal <- [|entityVal|] dot <- [|(.)|] keyVar <- newName "key" valName <- newName "value" xName <- newName "x" let idClause = normalClause [ConP (keyIdName t) []] (lens' `AppE` getId `AppE` setId) if entitySum t then return $ idClause : map (toSumClause lens' keyVar valName xName) (entityFields t) else return $ idClause : map (toClause lens' getVal dot keyVar valName xName) (entityFields t) where toClause lens' getVal dot keyVar valName xName f = normalClause [ConP (filterConName mps t f) []] (lens' `AppE` getter `AppE` setter) where fieldName = mkName $ unpack $ recName mps (entityHaskell t) (fieldHaskell f) getter = InfixE (Just $ VarE fieldName) dot (Just getVal) setter = LamE [ ConP 'Entity [VarP keyVar, VarP valName] , VarP xName ] $ ConE 'Entity `AppE` VarE keyVar `AppE` RecUpdE (VarE valName) [(fieldName, VarE xName)] toSumClause lens' keyVar valName xName f = normalClause [ConP (filterConName mps t f) []] (lens' `AppE` getter `AppE` setter) where emptyMatch = Match WildP (NormalB $ VarE 'error `AppE` LitE (StringL "Tried to use fieldLens on a Sum type")) [] getter = LamE [ ConP 'Entity [WildP, VarP valName] ] $ CaseE (VarE valName) $ Match (ConP (sumConstrName mps t f) [VarP xName]) (NormalB $ VarE xName) [] -- FIXME It would be nice if the types expressed that the Field is -- a sum type and therefore could result in Maybe. : if length (entityFields t) > 1 then [emptyMatch] else [] setter = LamE [ ConP 'Entity [VarP keyVar, WildP] , VarP xName ] $ ConE 'Entity `AppE` VarE keyVar `AppE` (ConE (sumConstrName mps t f) `AppE` VarE xName) -- | declare the key type and associated instances -- @'PathPiece'@, @'ToHttpApiData'@ and @'FromHttpApiData'@ instances are only generated for a Key with one field mkKeyTypeDec :: MkPersistSettings -> EntityDef -> Q (Dec, [Dec]) mkKeyTypeDec mps t = do (instDecs, i) <- if mpsGeneric mps then if not useNewtype then do pfDec <- pfInstD return (pfDec, [''Generic]) else do gi <- genericNewtypeInstances return (gi, []) else if not useNewtype then do pfDec <- pfInstD return (pfDec, [''Show, ''Read, ''Eq, ''Ord, ''Generic]) else do let allInstances = [''Show, ''Read, ''Eq, ''Ord, ''PathPiece, ''ToHttpApiData, ''FromHttpApiData, ''PersistField, ''PersistFieldSql, ''ToJSON, ''FromJSON] if customKeyType then return ([], allInstances) else do bi <- backendKeyI return (bi, allInstances) #if MIN_VERSION_template_haskell(2,12,0) cxti <- mapM conT i let kd = if useNewtype then NewtypeInstD [] k [recordType] Nothing dec [DerivClause Nothing cxti] else DataInstD [] k [recordType] Nothing [dec] [DerivClause Nothing cxti] #elif MIN_VERSION_template_haskell(2,11,0) cxti <- mapM conT i let kd = if useNewtype then NewtypeInstD [] k [recordType] Nothing dec cxti else DataInstD [] k [recordType] Nothing [dec] cxti #else let kd = if useNewtype then NewtypeInstD [] k [recordType] dec i else DataInstD [] k [recordType] [dec] i #endif return (kd, instDecs) where keyConE = keyConExp t unKeyE = unKeyExp t dec = RecC (keyConName t) (keyFields mps t) k = ''Key recordType = genericDataType mps (entityHaskell t) backendT pfInstD = -- FIXME: generate a PersistMap instead of PersistList [d|instance PersistField (Key $(A.pure recordType)) where toPersistValue = PersistList . keyToValues fromPersistValue (PersistList l) = keyFromValues l fromPersistValue got = error $ "fromPersistValue: expected PersistList, got: " `mappend` show got instance PersistFieldSql (Key $(pure recordType)) where sqlType _ = SqlString instance ToJSON (Key $(pure recordType)) instance FromJSON (Key $(pure recordType)) |] keyStringL = StringL . keyString -- ghc 7.6 cannot parse the left arrow Ident $() <- lexP keyPattern = BindS (ConP 'Ident [LitP $ keyStringL t]) backendKeyGenericI = [d| instance PersistStore $(pure backendT) => ToBackendKey $(pure backendT) $(pure recordType) where toBackendKey = $(return unKeyE) fromBackendKey = $(return keyConE) |] backendKeyI = let bdt = backendDataType mps in [d| instance ToBackendKey $(pure bdt) $(pure recordType) where toBackendKey = $(return unKeyE) fromBackendKey = $(return keyConE) |] -- truly unfortunate that TH doesn't support standalone deriving -- https://ghc.haskell.org/trac/ghc/ticket/8100 genericNewtypeInstances = do instances <- [|lexP|] >>= \lexPE -> [| step readPrec >>= return . ($(pure keyConE) )|] >>= \readE -> do alwaysInstances <- [d|instance Show (BackendKey $(pure backendT)) => Show (Key $(pure recordType)) where showsPrec i x = showParen (i > app_prec) $ (showString $ $(pure $ LitE $ keyStringL t) `mappend` " ") . showsPrec i ($(return unKeyE) x) where app_prec = (10::Int) instance Read (BackendKey $(pure backendT)) => Read (Key $(pure recordType)) where readPrec = parens $ (prec app_prec $ $(pure $ DoE [keyPattern lexPE, NoBindS readE])) where app_prec = (10::Int) instance Eq (BackendKey $(pure backendT)) => Eq (Key $(pure recordType)) where x == y = ($(return unKeyE) x) == ($(return unKeyE) y) instance Ord (BackendKey $(pure backendT)) => Ord (Key $(pure recordType)) where compare x y = compare ($(return unKeyE) x) ($(return unKeyE) y) instance ToHttpApiData (BackendKey $(pure backendT)) => ToHttpApiData (Key $(pure recordType)) where toUrlPiece = toUrlPiece . $(return unKeyE) instance FromHttpApiData (BackendKey $(pure backendT)) => FromHttpApiData(Key $(pure recordType)) where parseUrlPiece = fmap $(return keyConE) . parseUrlPiece instance PathPiece (BackendKey $(pure backendT)) => PathPiece (Key $(pure recordType)) where toPathPiece = toPathPiece . $(return unKeyE) fromPathPiece = fmap $(return keyConE) . fromPathPiece instance PersistField (BackendKey $(pure backendT)) => PersistField (Key $(pure recordType)) where toPersistValue = toPersistValue . $(return unKeyE) fromPersistValue = fmap $(return keyConE) . fromPersistValue instance PersistFieldSql (BackendKey $(pure backendT)) => PersistFieldSql (Key $(pure recordType)) where sqlType = sqlType . fmap $(return unKeyE) instance ToJSON (BackendKey $(pure backendT)) => ToJSON (Key $(pure recordType)) where toJSON = toJSON . $(return unKeyE) instance FromJSON (BackendKey $(pure backendT)) => FromJSON (Key $(pure recordType)) where parseJSON = fmap $(return keyConE) . parseJSON |] if customKeyType then return alwaysInstances else fmap (alwaysInstances `mappend`) backendKeyGenericI return instances useNewtype = pkNewtype mps t customKeyType = not (defaultIdType t) || not useNewtype || isJust (entityPrimary t) keyIdName :: EntityDef -> Name keyIdName = mkName . unpack . keyIdText keyIdText :: EntityDef -> Text keyIdText t = (unHaskellName $ entityHaskell t) `mappend` "Id" unKeyName :: EntityDef -> Name unKeyName t = mkName $ "un" `mappend` keyString t unKeyExp :: EntityDef -> Exp unKeyExp = VarE . unKeyName backendT :: Type backendT = VarT backendName backendName :: Name backendName = mkName "backend" keyConName :: EntityDef -> Name keyConName t = mkName $ resolveConflict $ keyString t where resolveConflict kn = if conflict then kn `mappend` "'" else kn conflict = any ((== HaskellName "key") . fieldHaskell) $ entityFields t keyConExp :: EntityDef -> Exp keyConExp = ConE . keyConName keyString :: EntityDef -> String keyString = unpack . keyText keyText :: EntityDef -> Text keyText t = unHaskellName (entityHaskell t) ++ "Key" pkNewtype :: MkPersistSettings -> EntityDef -> Bool pkNewtype mps t = length (keyFields mps t) < 2 defaultIdType :: EntityDef -> Bool defaultIdType t = fieldType (entityId t) == FTTypeCon Nothing (keyIdText t) keyFields :: MkPersistSettings -> EntityDef -> [(Name, Strict, Type)] keyFields mps t = case entityPrimary t of Just pdef -> map primaryKeyVar $ (compositeFields pdef) Nothing -> if defaultIdType t then [idKeyVar backendKeyType] else [idKeyVar $ ftToType $ fieldType $ entityId t] where backendKeyType | mpsGeneric mps = ConT ''BackendKey `AppT` backendT | otherwise = ConT ''BackendKey `AppT` mpsBackend mps idKeyVar ft = (unKeyName t, notStrict, ft) primaryKeyVar fd = ( keyFieldName mps t fd , notStrict , ftToType $ fieldType fd ) keyFieldName :: MkPersistSettings -> EntityDef -> FieldDef -> Name keyFieldName mps t fd | pkNewtype mps t = unKeyName t | otherwise = mkName $ unpack $ lowerFirst (keyText t) `mappend` (unHaskellName $ fieldHaskell fd) mkKeyToValues :: MkPersistSettings -> EntityDef -> Q Dec mkKeyToValues mps t = do (p, e) <- case entityPrimary t of Nothing -> ([],) A.<$> [|(:[]) . toPersistValue . $(return $ unKeyExp t)|] Just pdef -> return $ toValuesPrimary pdef return $ FunD 'keyToValues $ return $ normalClause p e where toValuesPrimary pdef = ( [VarP recordName] , ListE $ map (\fd -> VarE 'toPersistValue `AppE` (VarE (keyFieldName mps t fd) `AppE` VarE recordName)) $ compositeFields pdef ) recordName = mkName "record" normalClause :: [Pat] -> Exp -> Clause normalClause p e = Clause p (NormalB e) [] mkKeyFromValues :: MkPersistSettings -> EntityDef -> Q Dec mkKeyFromValues _mps t = do clauses <- case entityPrimary t of Nothing -> do e <- [|fmap $(return $ keyConE) . fromPersistValue . headNote|] return $ [normalClause [] e] Just pdef -> fromValues t "keyFromValues" keyConE (compositeFields pdef) return $ FunD 'keyFromValues clauses where keyConE = keyConExp t headNote :: [PersistValue] -> PersistValue headNote (x:[]) = x headNote xs = error $ "mkKeyFromValues: expected a list of one element, got: " `mappend` show xs fromValues :: EntityDef -> Text -> Exp -> [FieldDef] -> Q [Clause] fromValues t funName conE fields = do x <- newName "x" let funMsg = entityText t `mappend` ": " `mappend` funName `mappend` " failed on: " patternMatchFailure <- [|Left $ mappend funMsg (pack $ show $(return $ VarE x))|] suc <- patternSuccess fields return [ suc, normalClause [VarP x] patternMatchFailure ] where patternSuccess [] = do rightE <- [|Right|] return $ normalClause [ListP []] (rightE `AppE` conE) patternSuccess fieldsNE = do x1 <- newName "x1" restNames <- mapM (\i -> newName $ "x" `mappend` show i) [2..length fieldsNE] (fpv1:mkPersistValues) <- mapM mkPvFromFd fieldsNE app1E <- [|(<$>)|] let conApp = infixFromPersistValue app1E fpv1 conE x1 applyE <- [|(A.<*>)|] let applyFromPersistValue = infixFromPersistValue applyE return $ normalClause [ListP $ map VarP (x1:restNames)] (foldl' (\exp (name, fpv) -> applyFromPersistValue fpv exp name) conApp (zip restNames mkPersistValues)) where infixFromPersistValue applyE fpv exp name = UInfixE exp applyE (fpv `AppE` VarE name) mkPvFromFd = mkPersistValue . unHaskellName . fieldHaskell mkPersistValue fieldName = [|mapLeft (fieldError fieldName) . fromPersistValue|] mkEntity :: EntityMap -> MkPersistSettings -> EntityDef -> Q [Dec] mkEntity entMap mps t = do t' <- liftAndFixKeys entMap t let nameT = unHaskellName entName let nameS = unpack nameT let clazz = ConT ''PersistEntity `AppT` genDataType tpf <- mkToPersistFields mps nameS t fpv <- mkFromPersistValues mps t utv <- mkUniqueToValues $ entityUniques t puk <- mkUniqueKeys t fkc <- mapM (mkForeignKeysComposite mps t) $ entityForeigns t let primaryField = entityId t fields <- mapM (mkField mps t) $ primaryField : entityFields t toFieldNames <- mkToFieldNames $ entityUniques t (keyTypeDec, keyInstanceDecs) <- mkKeyTypeDec mps t keyToValues' <- mkKeyToValues mps t keyFromValues' <- mkKeyFromValues mps t let addSyn -- FIXME maybe remove this | mpsGeneric mps = (:) $ TySynD (mkName nameS) [] $ genericDataType mps entName $ mpsBackend mps | otherwise = id lensClauses <- mkLensClauses mps t lenses <- mkLenses mps t let instanceConstraint = if not (mpsGeneric mps) then [] else [mkClassP ''PersistStore [backendT]] dtd <- dataTypeDec mps t return $ addSyn $ dtd : mconcat fkc `mappend` ([ TySynD (keyIdName t) [] $ ConT ''Key `AppT` ConT (mkName nameS) , instanceD instanceConstraint clazz $ [ uniqueTypeDec mps t , keyTypeDec , keyToValues' , keyFromValues' , FunD 'entityDef [normalClause [WildP] t'] , tpf , FunD 'fromPersistValues fpv , toFieldNames , utv , puk , DataInstD [] ''EntityField [ genDataType , VarT $ mkName "typ" ] #if MIN_VERSION_template_haskell(2,11,0) Nothing #endif (map fst fields) [] , FunD 'persistFieldDef (map snd fields) , TySynInstD ''PersistEntityBackend #if MIN_VERSION_template_haskell(2,9,0) (TySynEqn [genDataType] (backendDataType mps)) #else [genDataType] (backendDataType mps) #endif , FunD 'persistIdField [normalClause [] (ConE $ keyIdName t)] , FunD 'fieldLens lensClauses ] ] `mappend` lenses) `mappend` keyInstanceDecs where genDataType = genericDataType mps entName backendT entName = entityHaskell t entityText :: EntityDef -> Text entityText = unHaskellName . entityHaskell mkLenses :: MkPersistSettings -> EntityDef -> Q [Dec] mkLenses mps _ | not (mpsGenerateLenses mps) = return [] mkLenses _ ent | entitySum ent = return [] mkLenses mps ent = fmap mconcat $ forM (entityFields ent) $ \field -> do let lensName' = recNameNoUnderscore mps (entityHaskell ent) (fieldHaskell field) lensName = mkName $ unpack lensName' fieldName = mkName $ unpack $ "_" ++ lensName' needleN <- newName "needle" setterN <- newName "setter" fN <- newName "f" aN <- newName "a" yN <- newName "y" let needle = VarE needleN setter = VarE setterN f = VarE fN a = VarE aN y = VarE yN fT = mkName "f" -- FIXME if we want to get really fancy, then: if this field is the -- *only* Id field present, then set backend1 and backend2 to different -- values backend1 = backendName backend2 = backendName aT = maybeIdType mps field (Just backend1) Nothing bT = maybeIdType mps field (Just backend2) Nothing mkST backend = genericDataType mps (entityHaskell ent) (VarT backend) sT = mkST backend1 tT = mkST backend2 t1 `arrow` t2 = ArrowT `AppT` t1 `AppT` t2 vars = PlainTV fT : (if mpsGeneric mps then [PlainTV backend1{-, PlainTV backend2-}] else []) return [ SigD lensName $ ForallT vars [mkClassP ''Functor [VarT fT]] $ (aT `arrow` (VarT fT `AppT` bT)) `arrow` (sT `arrow` (VarT fT `AppT` tT)) , FunD lensName $ return $ Clause [VarP fN, VarP aN] (NormalB $ fmapE `AppE` setter `AppE` (f `AppE` needle)) [ FunD needleN [normalClause [] (VarE fieldName `AppE` a)] , FunD setterN $ return $ normalClause [VarP yN] (RecUpdE a [ (fieldName, y) ]) ] ] mkForeignKeysComposite :: MkPersistSettings -> EntityDef -> ForeignDef -> Q [Dec] mkForeignKeysComposite mps t ForeignDef {..} = do let fieldName f = mkName $ unpack $ recName mps (entityHaskell t) f let fname = fieldName foreignConstraintNameHaskell let reftableString = unpack $ unHaskellName $ foreignRefTableHaskell let reftableKeyName = mkName $ reftableString `mappend` "Key" let tablename = mkName $ unpack $ entityText t recordName <- newName "record" let fldsE = map (\((foreignName, _),_) -> VarE (fieldName $ foreignName) `AppE` VarE recordName) foreignFields let mkKeyE = foldl' AppE (maybeExp foreignNullable $ ConE reftableKeyName) fldsE let fn = FunD fname [normalClause [VarP recordName] mkKeyE] let t2 = maybeTyp foreignNullable $ ConT ''Key `AppT` ConT (mkName reftableString) let sig = SigD fname $ (ArrowT `AppT` (ConT tablename)) `AppT` t2 return [sig, fn] maybeExp :: Bool -> Exp -> Exp maybeExp may exp | may = fmapE `AppE` exp | otherwise = exp maybeTyp :: Bool -> Type -> Type maybeTyp may typ | may = ConT ''Maybe `AppT` typ | otherwise = typ -- | produce code similar to the following: -- -- @ -- instance PersistEntity e => PersistField e where -- toPersistValue = PersistMap $ zip columNames (map toPersistValue . toPersistFields) -- fromPersistValue (PersistMap o) = -- let columns = HM.fromList o -- in fromPersistValues $ map (\name -> -- case HM.lookup name columns of -- Just v -> v -- Nothing -> PersistNull -- fromPersistValue x = Left $ "Expected PersistMap, received: " ++ show x -- sqlType _ = SqlString -- @ persistFieldFromEntity :: MkPersistSettings -> EntityDef -> Q [Dec] persistFieldFromEntity mps e = do ss <- [|SqlString|] obj <- [|\ent -> PersistMap $ zip (map pack columnNames) (map toPersistValue $ toPersistFields ent)|] fpv <- [|\x -> let columns = HM.fromList x in fromPersistValues $ map (\(name) -> case HM.lookup (pack name) columns of Just v -> v Nothing -> PersistNull) $ columnNames |] compose <- [|(<=<)|] getPersistMap' <- [|getPersistMap|] return [ persistFieldInstanceD (mpsGeneric mps) typ [ FunD 'toPersistValue [ normalClause [] obj ] , FunD 'fromPersistValue [ normalClause [] (InfixE (Just fpv) compose $ Just getPersistMap') ] ] , persistFieldSqlInstanceD (mpsGeneric mps) typ [ sqlTypeFunD ss ] ] where typ = genericDataType mps (entityHaskell e) backendT entFields = entityFields e columnNames = map (unpack . unHaskellName . fieldHaskell) entFields -- | Apply the given list of functions to the same @EntityDef@s. -- -- This function is useful for cases such as: -- -- >>> share [mkSave "myDefs", mkPersist sqlSettings] [persistLowerCase|...|] share :: [[EntityDef] -> Q [Dec]] -> [EntityDef] -> Q [Dec] share fs x = fmap mconcat $ mapM ($ x) fs -- | Save the @EntityDef@s passed in under the given name. mkSave :: String -> [EntityDef] -> Q [Dec] mkSave name' defs' = do let name = mkName name' defs <- lift defs' return [ SigD name $ ListT `AppT` ConT ''EntityDef , FunD name [normalClause [] defs] ] data Dep = Dep { depTarget :: HaskellName , depSourceTable :: HaskellName , depSourceField :: HaskellName , depSourceNull :: IsNullable } -- | Generate a 'DeleteCascade' instance for the given @EntityDef@s. mkDeleteCascade :: MkPersistSettings -> [EntityDef] -> Q [Dec] mkDeleteCascade mps defs = do let deps = concatMap getDeps defs mapM (go deps) defs where getDeps :: EntityDef -> [Dep] getDeps def = concatMap getDeps' $ entityFields $ fixEntityDef def where getDeps' :: FieldDef -> [Dep] getDeps' field@FieldDef {..} = case foreignReference field of Just name -> return Dep { depTarget = name , depSourceTable = entityHaskell def , depSourceField = fieldHaskell , depSourceNull = nullable fieldAttrs } Nothing -> [] go :: [Dep] -> EntityDef -> Q Dec go allDeps EntityDef{entityHaskell = name} = do let deps = filter (\x -> depTarget x == name) allDeps key <- newName "key" let del = VarE 'delete let dcw = VarE 'deleteCascadeWhere just <- [|Just|] filt <- [|Filter|] eq <- [|Eq|] left <- [|Left|] let mkStmt :: Dep -> Stmt mkStmt dep = NoBindS $ dcw `AppE` ListE [ filt `AppE` ConE filtName `AppE` (left `AppE` val (depSourceNull dep)) `AppE` eq ] where filtName = filterConName' mps (depSourceTable dep) (depSourceField dep) val (Nullable ByMaybeAttr) = just `AppE` VarE key val _ = VarE key let stmts :: [Stmt] stmts = map mkStmt deps `mappend` [NoBindS $ del `AppE` VarE key] let entityT = genericDataType mps name backendT return $ instanceD [ mkClassP ''PersistQuery [backendT] , mkEqualP (ConT ''PersistEntityBackend `AppT` entityT) (ConT ''BaseBackend `AppT` backendT) ] (ConT ''DeleteCascade `AppT` entityT `AppT` backendT) [ FunD 'deleteCascade [normalClause [VarP key] (DoE stmts)] ] mkUniqueKeys :: EntityDef -> Q Dec mkUniqueKeys def | entitySum def = return $ FunD 'persistUniqueKeys [normalClause [WildP] (ListE [])] mkUniqueKeys def = do c <- clause return $ FunD 'persistUniqueKeys [c] where clause = do xs <- forM (entityFields def) $ \fd -> do let x = fieldHaskell fd x' <- newName $ '_' : unpack (unHaskellName x) return (x, x') let pcs = map (go xs) $ entityUniques def let pat = ConP (mkName $ unpack $ unHaskellName $ entityHaskell def) (map (VarP . snd) xs) return $ normalClause [pat] (ListE pcs) go :: [(HaskellName, Name)] -> UniqueDef -> Exp go xs (UniqueDef name _ cols _) = foldl' (go' xs) (ConE (mkName $ unpack $ unHaskellName name)) (map fst cols) go' :: [(HaskellName, Name)] -> Exp -> HaskellName -> Exp go' xs front col = let Just col' = lookup col xs in front `AppE` VarE col' sqlTypeFunD :: Exp -> Dec sqlTypeFunD st = FunD 'sqlType [ normalClause [WildP] st ] typeInstanceD :: Name -> Bool -- ^ include PersistStore backend constraint -> Type -> [Dec] -> Dec typeInstanceD clazz hasBackend typ = instanceD ctx (ConT clazz `AppT` typ) where ctx | hasBackend = [mkClassP ''PersistStore [backendT]] | otherwise = [] persistFieldInstanceD :: Bool -- ^ include PersistStore backend constraint -> Type -> [Dec] -> Dec persistFieldInstanceD = typeInstanceD ''PersistField persistFieldSqlInstanceD :: Bool -- ^ include PersistStore backend constraint -> Type -> [Dec] -> Dec persistFieldSqlInstanceD = typeInstanceD ''PersistFieldSql -- | Automatically creates a valid 'PersistField' instance for any datatype -- that has valid 'Show' and 'Read' instances. Can be very convenient for -- 'Enum' types. derivePersistField :: String -> Q [Dec] derivePersistField s = do ss <- [|SqlString|] tpv <- [|PersistText . pack . show|] fpv <- [|\dt v -> case fromPersistValue v of Left e -> Left e Right s' -> case reads $ unpack s' of (x, _):_ -> Right x [] -> Left $ pack "Invalid " ++ pack dt ++ pack ": " ++ s'|] return [ persistFieldInstanceD False (ConT $ mkName s) [ FunD 'toPersistValue [ normalClause [] tpv ] , FunD 'fromPersistValue [ normalClause [] (fpv `AppE` LitE (StringL s)) ] ] , persistFieldSqlInstanceD False (ConT $ mkName s) [ sqlTypeFunD ss ] ] -- | Automatically creates a valid 'PersistField' instance for any datatype -- that has valid 'ToJSON' and 'FromJSON' instances. For a datatype @T@ it -- generates instances similar to these: -- -- @ -- instance PersistField T where -- toPersistValue = PersistByteString . L.toStrict . encode -- fromPersistValue = (left T.pack) . eitherDecodeStrict' <=< fromPersistValue -- instance PersistFieldSql T where -- sqlType _ = SqlString -- @ derivePersistFieldJSON :: String -> Q [Dec] derivePersistFieldJSON s = do ss <- [|SqlString|] tpv <- [|PersistText . toJsonText|] fpv <- [|\dt v -> do text <- fromPersistValue v let bs' = TE.encodeUtf8 text case eitherDecodeStrict' bs' of Left e -> Left $ pack "JSON decoding error for " ++ pack dt ++ pack ": " ++ pack e ++ pack ". On Input: " ++ decodeUtf8 bs' Right x -> Right x|] return [ persistFieldInstanceD False (ConT $ mkName s) [ FunD 'toPersistValue [ normalClause [] tpv ] , FunD 'fromPersistValue [ normalClause [] (fpv `AppE` LitE (StringL s)) ] ] , persistFieldSqlInstanceD False (ConT $ mkName s) [ sqlTypeFunD ss ] ] -- | Creates a single function to perform all migrations for the entities -- defined here. One thing to be aware of is dependencies: if you have entities -- with foreign references, make sure to place those definitions after the -- entities they reference. mkMigrate :: String -> [EntityDef] -> Q [Dec] mkMigrate fun allDefs = do body' <- body return [ SigD (mkName fun) typ , FunD (mkName fun) [normalClause [] body'] ] where defs = filter isMigrated allDefs isMigrated def = not $ "no-migrate" `elem` entityAttrs def typ = ConT ''Migration entMap = M.fromList $ map (\ent -> (entityHaskell ent, ent)) allDefs body :: Q Exp body = case defs of [] -> [|return ()|] _ -> do defsName <- newName "defs" defsStmt <- do defs' <- mapM (liftAndFixKeys entMap) defs let defsExp = ListE defs' return $ LetS [ValD (VarP defsName) (NormalB defsExp) []] stmts <- mapM (toStmt $ VarE defsName) defs return (DoE $ defsStmt : stmts) toStmt :: Exp -> EntityDef -> Q Stmt toStmt defsExp ed = do u <- liftAndFixKeys entMap ed m <- [|migrate|] return $ NoBindS $ m `AppE` defsExp `AppE` u liftAndFixKeys :: EntityMap -> EntityDef -> Q Exp liftAndFixKeys entMap EntityDef{..} = [|EntityDef entityHaskell entityDB entityId entityAttrs $(ListE <$> mapM (liftAndFixKey entMap) entityFields) entityUniques entityForeigns entityDerives entityExtra entitySum |] liftAndFixKey :: EntityMap -> FieldDef -> Q Exp liftAndFixKey entMap (FieldDef a b c sqlTyp e f fieldRef) = [|FieldDef a b c $(sqlTyp') e f fieldRef'|] where (fieldRef', sqlTyp') = fromMaybe (fieldRef, lift sqlTyp) $ case fieldRef of ForeignRef refName _ft -> case M.lookup refName entMap of Nothing -> Nothing Just ent -> case fieldReference $ entityId ent of fr@(ForeignRef _Name ft) -> Just (fr, lift $ SqlTypeExp ft) _ -> Nothing _ -> Nothing instance Lift EntityDef where lift EntityDef{..} = [|EntityDef entityHaskell entityDB entityId entityAttrs entityFields entityUniques entityForeigns entityDerives entityExtra entitySum |] instance Lift FieldDef where lift (FieldDef a b c d e f g) = [|FieldDef a b c d e f g|] instance Lift UniqueDef where lift (UniqueDef a b c d) = [|UniqueDef a b c d|] instance Lift CompositeDef where lift (CompositeDef a b) = [|CompositeDef a b|] instance Lift ForeignDef where lift (ForeignDef a b c d e f g) = [|ForeignDef a b c d e f g|] -- | A hack to avoid orphans. class Lift' a where lift' :: a -> Q Exp instance Lift' Text where lift' = liftT instance Lift' a => Lift' [a] where lift' xs = do { xs' <- mapM lift' xs; return (ListE xs') } instance (Lift' k, Lift' v) => Lift' (M.Map k v) where lift' m = [|M.fromList $(fmap ListE $ mapM liftPair $ M.toList m)|] -- auto-lifting, means instances are overlapping #if MIN_VERSION_base(4,8,0) instance {-# OVERLAPPABLE #-} Lift' a => Lift a where #else instance Lift' a => Lift a where #endif lift = lift' packPTH :: String -> Text packPTH = pack #if !MIN_VERSION_text(0, 11, 2) {-# NOINLINE packPTH #-} #endif liftT :: Text -> Q Exp liftT t = [|packPTH $(lift (unpack t))|] liftPair :: (Lift' k, Lift' v) => (k, v) -> Q Exp liftPair (k, v) = [|($(lift' k), $(lift' v))|] instance Lift HaskellName where lift (HaskellName t) = [|HaskellName t|] instance Lift DBName where lift (DBName t) = [|DBName t|] instance Lift FieldType where lift (FTTypeCon Nothing t) = [|FTTypeCon Nothing t|] lift (FTTypeCon (Just x) t) = [|FTTypeCon (Just x) t|] lift (FTApp x y) = [|FTApp x y|] lift (FTList x) = [|FTList x|] instance Lift PersistFilter where lift Eq = [|Eq|] lift Ne = [|Ne|] lift Gt = [|Gt|] lift Lt = [|Lt|] lift Ge = [|Ge|] lift Le = [|Le|] lift In = [|In|] lift NotIn = [|NotIn|] lift (BackendSpecificFilter x) = [|BackendSpecificFilter x|] instance Lift PersistUpdate where lift Assign = [|Assign|] lift Add = [|Add|] lift Subtract = [|Subtract|] lift Multiply = [|Multiply|] lift Divide = [|Divide|] lift (BackendSpecificUpdate x) = [|BackendSpecificUpdate x|] instance Lift SqlType where lift SqlString = [|SqlString|] lift SqlInt32 = [|SqlInt32|] lift SqlInt64 = [|SqlInt64|] lift SqlReal = [|SqlReal|] lift (SqlNumeric x y) = [|SqlNumeric (fromInteger x') (fromInteger y')|] where x' = fromIntegral x :: Integer y' = fromIntegral y :: Integer lift SqlBool = [|SqlBool|] lift SqlDay = [|SqlDay|] lift SqlTime = [|SqlTime|] lift SqlDayTime = [|SqlDayTime|] lift SqlBlob = [|SqlBlob|] lift (SqlOther a) = [|SqlOther a|] -- Ent -- fieldName FieldType -- -- forall . typ ~ FieldType => EntFieldName -- -- EntFieldName = FieldDef .... mkField :: MkPersistSettings -> EntityDef -> FieldDef -> Q (Con, Clause) mkField mps et cd = do let con = ForallC [] [mkEqualP (VarT $ mkName "typ") $ maybeIdType mps cd Nothing Nothing] $ NormalC name [] bod <- lift cd let cla = normalClause [ConP name []] bod return (con, cla) where name = filterConName mps et cd maybeNullable :: FieldDef -> Bool maybeNullable fd = nullable (fieldAttrs fd) == Nullable ByMaybeAttr filterConName :: MkPersistSettings -> EntityDef -> FieldDef -> Name filterConName mps entity field = filterConName' mps (entityHaskell entity) (fieldHaskell field) filterConName' :: MkPersistSettings -> HaskellName -- ^ table -> HaskellName -- ^ field -> Name filterConName' mps entity field = mkName $ unpack $ concat [ if mpsPrefixFields mps || field == HaskellName "Id" then unHaskellName entity else "" , upperFirst $ unHaskellName field ] ftToType :: FieldType -> Type ftToType (FTTypeCon Nothing t) = ConT $ mkName $ unpack t -- This type is generated from the Quasi-Quoter. -- Adding this special case avoids users needing to import Data.Int ftToType (FTTypeCon (Just "Data.Int") "Int64") = ConT ''Int64 ftToType (FTTypeCon (Just m) t) = ConT $ mkName $ unpack $ concat [m, ".", t] ftToType (FTApp x y) = ftToType x `AppT` ftToType y ftToType (FTList x) = ListT `AppT` ftToType x infixr 5 ++ (++) :: Text -> Text -> Text (++) = append mkJSON :: MkPersistSettings -> EntityDef -> Q [Dec] mkJSON _ def | not ("json" `elem` entityAttrs def) = return [] mkJSON mps def = do pureE <- [|pure|] apE' <- [|(<*>)|] packE <- [|pack|] dotEqualE <- [|(.=)|] dotColonE <- [|(.:)|] dotColonQE <- [|(.:?)|] objectE <- [|object|] obj <- newName "obj" mzeroE <- [|mzero|] xs <- mapM (newName . unpack . unHaskellNameForJSON . fieldHaskell) $ entityFields def let conName = mkName $ unpack $ unHaskellName $ entityHaskell def typ = genericDataType mps (entityHaskell def) backendT toJSONI = typeInstanceD ''ToJSON (mpsGeneric mps) typ [toJSON'] toJSON' = FunD 'toJSON $ return $ normalClause [ConP conName $ map VarP xs] (objectE `AppE` ListE pairs) pairs = zipWith toPair (entityFields def) xs toPair f x = InfixE (Just (packE `AppE` LitE (StringL $ unpack $ unHaskellName $ fieldHaskell f))) dotEqualE (Just $ VarE x) fromJSONI = typeInstanceD ''FromJSON (mpsGeneric mps) typ [parseJSON'] parseJSON' = FunD 'parseJSON [ normalClause [ConP 'Object [VarP obj]] (foldl' (\x y -> InfixE (Just x) apE' (Just y)) (pureE `AppE` ConE conName) pulls ) , normalClause [WildP] mzeroE ] pulls = map toPull $ entityFields def toPull f = InfixE (Just $ VarE obj) (if maybeNullable f then dotColonQE else dotColonE) (Just $ AppE packE $ LitE $ StringL $ unpack $ unHaskellName $ fieldHaskell f) case mpsEntityJSON mps of Nothing -> return [toJSONI, fromJSONI] Just entityJSON -> do entityJSONIs <- if mpsGeneric mps then [d| #if MIN_VERSION_base(4, 6, 0) instance PersistStore $(pure backendT) => ToJSON (Entity $(pure typ)) where toJSON = $(varE (entityToJSON entityJSON)) instance PersistStore $(pure backendT) => FromJSON (Entity $(pure typ)) where parseJSON = $(varE (entityFromJSON entityJSON)) #endif |] else [d| instance ToJSON (Entity $(pure typ)) where toJSON = $(varE (entityToJSON entityJSON)) instance FromJSON (Entity $(pure typ)) where parseJSON = $(varE (entityFromJSON entityJSON)) |] return $ toJSONI : fromJSONI : entityJSONIs mkClassP :: Name -> [Type] -> Pred #if MIN_VERSION_template_haskell(2,10,0) mkClassP cla tys = foldl AppT (ConT cla) tys #else mkClassP = ClassP #endif mkEqualP :: Type -> Type -> Pred #if MIN_VERSION_template_haskell(2,10,0) mkEqualP tleft tright = foldl AppT EqualityT [tleft, tright] #else mkEqualP = EqualP #endif #if MIN_VERSION_template_haskell(2,11,0) notStrict :: Bang notStrict = Bang NoSourceUnpackedness NoSourceStrictness isStrict :: Bang isStrict = Bang NoSourceUnpackedness SourceStrict #else notStrict :: Strict notStrict = NotStrict isStrict :: Strict isStrict = IsStrict #endif instanceD :: Cxt -> Type -> [Dec] -> Dec #if MIN_VERSION_template_haskell(2,11,0) instanceD = InstanceD Nothing #else instanceD = InstanceD #endif -- entityUpdates :: EntityDef -> [(HaskellName, FieldType, IsNullable, PersistUpdate)] -- entityUpdates = -- concatMap go . entityFields -- where -- go FieldDef {..} = map (\a -> (fieldHaskell, fieldType, nullable fieldAttrs, a)) [minBound..maxBound] -- mkToUpdate :: String -> [(String, PersistUpdate)] -> Q Dec -- mkToUpdate name pairs = do -- pairs' <- mapM go pairs -- return $ FunD (mkName name) $ degen pairs' -- where -- go (constr, pu) = do -- pu' <- lift pu -- return $ normalClause [RecP (mkName constr) []] pu' -- mkToFieldName :: String -> [(String, String)] -> Dec -- mkToFieldName func pairs = -- FunD (mkName func) $ degen $ map go pairs -- where -- go (constr, name) = -- normalClause [RecP (mkName constr) []] (LitE $ StringL name) -- mkToValue :: String -> [String] -> Dec -- mkToValue func = FunD (mkName func) . degen . map go -- where -- go constr = -- let x = mkName "x" -- in normalClause [ConP (mkName constr) [VarP x]] -- (VarE 'toPersistValue `AppE` VarE x)