module Database.Persist.TH
(
persistWith
, persistUpperCase
, persistLowerCase
, persistFileWith
, persist
, persistFile
, mkPersist
, MkPersistSettings
, mpsBackend
, mpsGeneric
, mkPersistSettings
, sqlSettings
, sqlOnlySettings
, mkMigrate
, mkSave
, mkDeleteCascade
, share
, derivePersistField
, persistFieldFromEntity
, share2
) where
import Prelude hiding ((++), take, concat, splitAt)
import Database.Persist.EntityDef
import Database.Persist.Quasi
import Database.Persist.Store
import Database.Persist.Query.Internal
import Database.Persist.GenericSql (Migration, SqlPersist, migrate)
import Database.Persist.GenericSql.Raw (SqlBackend)
import Database.Persist.Util (nullable, IsNullable(..), WhyNullable(..))
import Language.Haskell.TH.Quote
import Language.Haskell.TH.Syntax
import Data.Char (toLower, toUpper)
import Control.Monad (forM, (<=<), mzero)
import Control.Monad.Trans.Control (MonadBaseControl)
import Control.Monad.IO.Class (MonadIO)
import qualified System.IO as SIO
import Data.Text (pack, Text, append, unpack, concat, uncons, cons)
import qualified Data.Text.IO as TIO
import Data.List (foldl')
import Data.Monoid (mappend, mconcat)
import qualified Data.Map as M
import Data.Aeson
( ToJSON (toJSON), FromJSON (parseJSON), (.=), object
, Value (Object), (.:), (.:?)
)
import Control.Applicative (pure, (<*>))
persistWith :: PersistSettings -> QuasiQuoter
persistWith ps = QuasiQuoter
{ quoteExp = lift . parse ps . pack
}
persist :: QuasiQuoter
persist = persistUpperCase
persistUpperCase :: QuasiQuoter
persistUpperCase = persistWith upperCaseSettings
persistLowerCase :: QuasiQuoter
persistLowerCase = persistWith lowerCaseSettings
persistFileWith :: PersistSettings -> FilePath -> Q Exp
persistFileWith ps fp = do
#ifdef GHC_7_4
qAddDependentFile fp
#endif
h <- qRunIO $ SIO.openFile fp SIO.ReadMode
qRunIO $ SIO.hSetEncoding h SIO.utf8_bom
s <- qRunIO $ TIO.hGetContents h
lift $ parse ps s
persistFile :: FilePath -> Q Exp
persistFile = persistFileWith upperCaseSettings
mkPersist :: MkPersistSettings -> [EntityDef] -> Q [Dec]
mkPersist mps ents = do
x <- fmap mconcat $ mapM (persistFieldFromEntity mps) ents
y <- fmap mconcat $ mapM (mkEntity mps) ents
z <- fmap mconcat $ mapM (mkJSON mps) ents
return $ mconcat [x, y, z]
data MkPersistSettings = MkPersistSettings
{ mpsBackend :: Type
, mpsGeneric :: Bool
}
mkPersistSettings :: Type
-> MkPersistSettings
mkPersistSettings t = MkPersistSettings
{ mpsBackend = t
, mpsGeneric = True
}
sqlSettings :: MkPersistSettings
sqlSettings = mkPersistSettings $ ConT ''SqlBackend
sqlOnlySettings :: MkPersistSettings
sqlOnlySettings = sqlSettings { mpsGeneric = False }
recName :: Text -> Text -> Text
recName dt f = lowerFirst dt ++ upperFirst f
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 -> Dec
dataTypeDec mps t =
DataD [] nameFinal paramsFinal constrs
$ map (mkName . unpack) $ entityDerives t
where
mkCol x (FieldDef n _ ty as) =
(mkName $ unpack $ recName x $ unHaskellName n,
NotStrict,
pairToType mps backend (ty, nullable as)
)
(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 $ unHaskellName $ entityHaskell t) $ entityFields t
backend = mkName "backend"
constrs
| entitySum t = map sumCon $ entityFields t
| otherwise = [RecC name cols]
sumCon fd@(FieldDef _ _ ty _) = NormalC
(sumConstrName t fd)
[(NotStrict, pairToType mps backend (ty, NotNullable))]
sumConstrName :: EntityDef -> FieldDef -> Name
sumConstrName t (FieldDef n _ _ _) = mkName $ unpack $ concat
[ unHaskellName $ entityHaskell t
, upperFirst $ unHaskellName n
, "Sum"
]
readMay :: Read a => String -> Maybe a
readMay s =
case reads s of
(x, _):_ -> Just x
[] -> Nothing
entityUpdates :: EntityDef -> [(HaskellName, FieldType, IsNullable, PersistUpdate)]
entityUpdates =
concatMap go . entityFields
where
go (FieldDef x _ y as) = map (\a -> (x, y, nullable as, a)) [minBound..maxBound]
uniqueTypeDec :: MkPersistSettings -> EntityDef -> Dec
uniqueTypeDec mps t =
DataInstD [] ''Unique
[genericDataType mps (unHaskellName $ entityHaskell t) $ VarT backend]
(map (mkUnique mps backend t) $ entityUniques t)
[]
where
backend = mkName "backend"
mkUnique :: MkPersistSettings -> Name -> EntityDef -> UniqueDef -> Con
mkUnique mps backend 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 :: (FieldType, IsNullable) -> (Strict, Type)
go (_, Nullable _) | not force = error nullErrMsg
go (ft, y) = (NotStrict, pairToType mps backend (ft, y))
lookup3 :: Text -> [FieldDef] -> (FieldType, IsNullable)
lookup3 s [] =
error $ unpack $ "Column not found: " ++ s ++ " in unique " ++ constr
lookup3 x ((FieldDef (HaskellName x') _ y z):rest)
| x == x' = (y, nullable z)
| 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. ***" ]
pairToType :: MkPersistSettings
-> Name
-> (FieldType, IsNullable)
-> Type
pairToType mps backend (s, Nullable ByMaybeAttr) =
ConT (mkName "Maybe") `AppT` idType mps backend s
pairToType mps backend (s, _) = idType mps backend s
backendDataType :: MkPersistSettings -> Type
backendDataType mps
| mpsGeneric mps = VarT $ mkName "backend"
| otherwise = mpsBackend mps
genericDataType :: MkPersistSettings
-> Text
-> Type
-> Type
genericDataType mps typ' backend
| mpsGeneric mps = ConT (mkName $ unpack $ typ' ++ "Generic") `AppT` backend
| otherwise = ConT $ mkName $ unpack typ'
idType :: MkPersistSettings -> Name -> FieldType -> Type
idType mps backend typ =
case stripId typ of
Just typ' ->
ConT ''KeyBackend
`AppT` backend'
`AppT` genericDataType mps typ' (VarT backend)
Nothing -> ftToType typ
where
backend'
| mpsGeneric mps = VarT backend
| otherwise = mpsBackend mps
degen :: [Clause] -> [Clause]
degen [] =
let err = VarE (mkName "error") `AppE` LitE (StringL
"Degenerate case, should never happen")
in [Clause [WildP] (NormalB err) []]
degen x = x
mkToPersistFields :: String -> EntityDef -> Q Dec
mkToPersistFields constr ed@EntityDef { entitySum = isSum, entityFields = fields } = do
clauses <-
if isSum
then sequence $ zipWith goSum fields [1..]
else fmap return go
return $ FunD (mkName "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 $ Clause [pat] (NormalB bod) []
fieldCount = length fields
goSum :: FieldDef -> Int -> Q Clause
goSum fd idx = do
let name = sumConstrName 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 = NormalB $ ListE $ mconcat
[ before
, [sp `AppE` VarE x]
, after
]
return $ Clause [ConP name [VarP x]] body []
mkToFieldNames :: [UniqueDef] -> Q Dec
mkToFieldNames pairs = do
pairs' <- mapM go pairs
return $ FunD (mkName "persistUniqueToFieldNames") $ degen pairs'
where
go (UniqueDef constr _ names _) = do
names' <- lift names
return $
Clause
[RecP (mkName $ unpack $ unHaskellName constr) []]
(NormalB names')
[]
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 $ Clause [RecP (mkName constr) []] (NormalB pu') []
mkUniqueToValues :: [UniqueDef] -> Q Dec
mkUniqueToValues pairs = do
pairs' <- mapM go pairs
return $ FunD (mkName "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 $ Clause [pat] (NormalB bod) []
mkToFieldName :: String -> [(String, String)] -> Dec
mkToFieldName func pairs =
FunD (mkName func) $ degen $ map go pairs
where
go (constr, name) =
Clause [RecP (mkName constr) []] (NormalB $ LitE $ StringL name) []
mkToOrder :: [(String, Exp)] -> Dec
mkToOrder pairs =
FunD (mkName "persistOrderToOrder") $ degen $ map go pairs
where
go (constr, val) =
Clause [RecP (mkName constr) []] (NormalB val) []
mkToValue :: String -> [String] -> Dec
mkToValue func = FunD (mkName func) . degen . map go
where
go constr =
let x = mkName "x"
in Clause [ConP (mkName constr) [VarP x]]
(NormalB $ VarE (mkName "toPersistValue") `AppE` VarE x)
[]
mkHalfDefined :: Name -> Int -> Dec
mkHalfDefined constr count' =
FunD (mkName "halfDefined")
[Clause [] (NormalB
$ foldl AppE (ConE constr)
(replicate count' $ VarE $ mkName "undefined")) []]
isNotNull :: PersistValue -> Bool
isNotNull PersistNull = False
isNotNull _ = True
mkFromPersistValues :: EntityDef -> Q [Clause]
mkFromPersistValues t@(EntityDef { entitySum = False }) = do
nothing <- [|Left $(liftT "Invalid fromPersistValues input")|]
let cons' = ConE $ mkName $ unpack $ unHaskellName $ entityHaskell t
xs <- mapM (const $ newName "x") $ entityFields t
fs <- [|fromPersistValue|]
let xs' = map (AppE fs . VarE) xs
let pat = ListP $ map VarP xs
ap' <- [|(<*>)|]
just <- [|Right|]
let cons'' = just `AppE` cons'
return
[ Clause [pat] (NormalB $ foldl (go ap') cons'' xs') []
, Clause [WildP] (NormalB nothing) []
]
where
go ap' x y = InfixE (Just x) ap' (Just y)
mkFromPersistValues t@(EntityDef { entitySum = True }) = do
nothing <- [|Left $(liftT "Invalid fromPersistValues input: sum type with all nulls")|]
clauses <- mkClauses [] $ entityFields t
return $ clauses `mappend` [Clause [WildP] (NormalB nothing) []]
where
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 t field
fmap' <- [|fmap|]
fs <- [|fromPersistValue $(return $ VarE x)|]
let guard' = NormalG $ VarE 'isNotNull `AppE` VarE x
let clause = Clause [pat] (GuardedB [(guard', InfixE (Just constr) fmap' (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
lens :: (s -> a) -> (s -> b -> t) -> Lens s t a b
lens sa sbt afb s = fmap (sbt s) (afb $ sa s)
mkLensClauses :: EntityDef -> Q [Clause]
mkLensClauses t = do
lens' <- [|lens|]
getId <- [|entityKey|]
setId <- [|\(Entity _ val) key -> Entity key val|]
getVal <- [|entityVal|]
dot <- [|(.)|]
keyName <- newName "key"
valName <- newName "val"
xName <- newName "x"
let idClause = Clause
[ConP (mkName $ unpack $ unHaskellName (entityHaskell t) ++ "Id") []]
(NormalB $ lens' `AppE` getId `AppE` setId)
[]
if entitySum t
then return $ idClause : map (toSumClause lens' getVal dot keyName valName xName) (entityFields t)
else return $ idClause : map (toClause lens' getVal dot keyName valName xName) (entityFields t)
where
toClause lens' getVal dot keyName valName xName f = Clause
[ConP (mkName $ unpack $ unHaskellName (entityHaskell t) ++ upperFirst (unHaskellName $ fieldHaskell f)) []]
(NormalB $ lens' `AppE` getter `AppE` setter)
[]
where
fieldName = mkName $ unpack $ recName (unHaskellName $ entityHaskell t) (unHaskellName $ fieldHaskell f)
getter = InfixE (Just $ VarE fieldName) dot (Just getVal)
setter = LamE
[ ConP 'Entity [VarP keyName, VarP valName]
, VarP xName
]
$ ConE 'Entity `AppE` VarE keyName `AppE` RecUpdE
(VarE valName)
[(fieldName, VarE xName)]
toSumClause lens' getVal dot keyName valName xName f = Clause
[ConP (mkName $ unpack $ unHaskellName (entityHaskell t) ++ upperFirst (unHaskellName $ fieldHaskell f)) []]
(NormalB $ lens' `AppE` getter `AppE` setter)
[]
where
fieldName = mkName $ unpack $ recName (unHaskellName $ entityHaskell t) (unHaskellName $ fieldHaskell f)
getter = LamE
[ ConP 'Entity [WildP, VarP valName]
] $ CaseE (VarE valName)
[ Match (ConP (sumConstrName t f) [VarP xName]) (NormalB $ VarE xName) []
, Match WildP (NormalB $ VarE 'error `AppE` LitE (StringL "Tried to use fieldLens on a Sum type")) []
]
setter = LamE
[ ConP 'Entity [VarP keyName, WildP]
, VarP xName
]
$ ConE 'Entity `AppE` VarE keyName `AppE` (ConE (sumConstrName t f) `AppE` VarE xName)
mkEntity :: MkPersistSettings -> EntityDef -> Q [Dec]
mkEntity mps t = do
t' <- lift t
let nameT = unHaskellName $ entityHaskell t
let nameS = unpack nameT
let clazz = ConT ''PersistEntity `AppT` genericDataType mps (unHaskellName $ entityHaskell t) (VarT $ mkName "backend")
tpf <- mkToPersistFields nameS t
fpv <- mkFromPersistValues t
utv <- mkUniqueToValues $ entityUniques t
puk <- mkUniqueKeys t
fields <- mapM (mkField mps t) $ FieldDef
(HaskellName "Id")
(entityID t)
(FTTypeCon Nothing $ unHaskellName (entityHaskell t) ++ "Id")
[]
: entityFields t
toFieldNames <- mkToFieldNames $ entityUniques t
let addSyn
| mpsGeneric mps = (:) $
TySynD (mkName nameS) [] $
genericDataType mps nameT $ mpsBackend mps
| otherwise = id
lensClauses <- mkLensClauses t
return $ addSyn
[ dataTypeDec mps t
, TySynD (mkName $ unpack $ unHaskellName (entityHaskell t) ++ "Id") [] $
ConT ''KeyBackend `AppT` mpsBackend mps `AppT` ConT (mkName nameS)
, InstanceD [] clazz $
[ uniqueTypeDec mps t
, FunD (mkName "entityDef") [Clause [WildP] (NormalB t') []]
, tpf
, FunD (mkName "fromPersistValues") fpv
, mkHalfDefined
(if entitySum t
then sumConstrName t (head $ entityFields t)
else mkName nameS)
(if entitySum t then 1 else length $ entityFields t)
, toFieldNames
, utv
, puk
, DataInstD
[]
''EntityField
[ genericDataType mps nameT $ VarT $ mkName "backend"
, VarT $ mkName "typ"
]
(map fst fields)
[]
, FunD (mkName "persistFieldDef") (map snd fields)
, TySynInstD
(mkName "PersistEntityBackend")
[genericDataType mps (unHaskellName $ entityHaskell t) $ VarT $ mkName "backend"]
(backendDataType mps)
, FunD (mkName "persistIdField") [Clause [] (NormalB $ ConE $ mkName $ unpack $ unHaskellName (entityHaskell t) ++ "Id") []]
, FunD (mkName "fieldLens") lensClauses
]
]
persistFieldFromEntity :: MkPersistSettings -> EntityDef -> Q [Dec]
persistFieldFromEntity mps e = do
ss <- [|SqlString|]
let columnNames = map (unpack . unHaskellName . fieldHaskell) (entityFields e)
obj <- [|\ent -> PersistMap $ zip (map pack columnNames) (map toPersistValue $ toPersistFields ent)|]
fpv <- [|\x -> fromPersistValues $ map (\(_,v) -> case fromPersistValue v of
Left e' -> error $ unpack e'
Right r -> r) x|]
let typ = genericDataType mps (pack entityName) $ VarT $ mkName "backend"
compose <- [|(<=<)|]
getPersistMap' <- [|getPersistMap|]
return
[ persistFieldInstanceD typ
[ sqlTypeFunD ss
, FunD (mkName "toPersistValue") [ Clause [] (NormalB obj) [] ]
, FunD (mkName "fromPersistValue")
[ Clause [] (NormalB $ InfixE (Just fpv) compose $ Just getPersistMap') []
]
]
]
where
entityName = (unpack $ unHaskellName $ entityHaskell e)
updateConName :: Text -> Text -> PersistUpdate -> Text
updateConName name s pu = concat
[ name
, upperFirst s
, case pu of
Assign -> ""
_ -> pack $ show pu
]
share :: [[EntityDef] -> Q [Dec]] -> [EntityDef] -> Q [Dec]
share fs x = fmap mconcat $ mapM ($ x) fs
share2 :: ([EntityDef] -> Q [Dec])
-> ([EntityDef] -> Q [Dec])
-> [EntityDef]
-> Q [Dec]
share2 f g x = do
y <- f x
z <- g x
return $ y `mappend` z
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 [Clause [] (NormalB defs) []]
]
data Dep = Dep
{ depTarget :: Text
, depSourceTable :: HaskellName
, depSourceField :: HaskellName
, depSourceNull :: IsNullable
}
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 def
where
getDeps' :: FieldDef -> [Dep]
getDeps' (FieldDef name _ ftyp attribs) =
case stripId ftyp of
Just f ->
return Dep
{ depTarget = f
, depSourceTable = entityHaskell def
, depSourceField = name
, depSourceNull = nullable attribs
}
Nothing -> []
go :: [Dep] -> EntityDef -> Q Dec
go allDeps EntityDef{entityHaskell = name} = do
let deps = filter (\x -> depTarget x == unHaskellName 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 (mkName $ unpack filtName)
`AppE` (left `AppE` val (depSourceNull dep))
`AppE` eq
]
where
filtName = unHaskellName (depSourceTable dep) ++
upperFirst (unHaskellName $ 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 (unHaskellName name) $ VarT $ mkName "backend"
return $
InstanceD
[ ClassP ''PersistQuery [VarT $ mkName "m"]
, EqualP (ConT ''PersistEntityBackend `AppT` entityT) (ConT ''PersistMonadBackend `AppT` VarT (mkName "m"))
]
(ConT ''DeleteCascade `AppT` entityT `AppT` VarT (mkName "m"))
[ FunD (mkName "deleteCascade")
[Clause [VarP key] (NormalB $ DoE stmts) []]
]
mkUniqueKeys :: EntityDef -> Q Dec
mkUniqueKeys def | entitySum def =
return $ FunD (mkName "persistUniqueKeys") [Clause [WildP] (NormalB $ ListE []) []]
mkUniqueKeys def = do
c <- clause
return $ FunD (mkName "persistUniqueKeys") [c]
where
clause = do
xs <- forM (entityFields def) $ \(FieldDef x _ _ _) -> do
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 $ Clause [pat] (NormalB $ 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 (mkName "sqlType")
[ Clause [WildP] (NormalB st) [] ]
persistFieldInstanceD :: Type -> [Dec] -> Dec
persistFieldInstanceD typ =
InstanceD [] (ConT ''PersistField `AppT` typ)
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 $ "Invalid " ++ dt ++ ": " ++ s'|]
return
[ persistFieldInstanceD (ConT $ mkName s)
[ sqlTypeFunD ss
, FunD (mkName "toPersistValue")
[ Clause [] (NormalB tpv) []
]
, FunD (mkName "fromPersistValue")
[ Clause [] (NormalB $ fpv `AppE` LitE (StringL s)) []
]
]
]
mkMigrate :: String -> [EntityDef] -> Q [Dec]
mkMigrate fun allDefs = do
body' <- body
return
[ SigD (mkName fun) typ
, FunD (mkName fun) [Clause [] (NormalB body') []]
]
where
defs = filter isMigrated allDefs
isMigrated def = not $ "no-migrate" `elem` entityAttrs def
typ = ForallT [PlainTV $ mkName "m"]
[ ClassP ''MonadBaseControl [ConT ''IO, VarT $ mkName "m"]
, ClassP ''MonadIO [VarT $ mkName "m"]
]
$ ConT ''Migration `AppT` (ConT ''SqlPersist `AppT` VarT (mkName "m"))
body :: Q Exp
body =
case defs of
[] -> [|return ()|]
_ -> do
defsName <- newName "defs"
defsStmt <- do
u <- [|undefined|]
e <- [|entityDef|]
let defsExp = ListE $ map (AppE e . undefinedEntityTH u) 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 <- [|undefined|]
m <- [|migrate|]
return $ NoBindS $ m `AppE` defsExp `AppE` (undefinedEntityTH u ed)
undefinedEntityTH :: Exp -> EntityDef -> Exp
undefinedEntityTH u = SigE u . ConT . mkName . unpack . unHaskellName . entityHaskell
instance Lift EntityDef where
lift (EntityDef a b c d e f g h i) =
[|EntityDef
$(lift a)
$(lift b)
$(lift c)
$(liftTs d)
$(lift e)
$(lift f)
$(liftTs g)
$(liftMap h)
$(lift i)
|]
instance Lift FieldDef where
lift (FieldDef a b c d) = [|FieldDef $(lift a) $(lift b) $(lift c) $(liftTs d)|]
instance Lift UniqueDef where
lift (UniqueDef a b c d) = [|UniqueDef $(lift a) $(lift b) $(lift c) $(liftTs d)|]
pack' :: String -> Text
pack' = pack
#if !MIN_VERSION_text(0, 11, 2)
#endif
liftT :: Text -> Q Exp
liftT t = [|pack' $(lift (unpack t))|]
liftTs :: [Text] -> Q Exp
liftTs = fmap ListE . mapM liftT
liftTss :: [[Text]] -> Q Exp
liftTss = fmap ListE . mapM liftTs
liftMap :: M.Map Text [[Text]] -> Q Exp
liftMap m = [|M.fromList $(fmap ListE $ mapM liftPair $ M.toList m)|]
liftPair :: (Text, [[Text]]) -> Q Exp
liftPair (t, ts) = [|($(liftT t), $(liftTss ts))|]
instance Lift HaskellName where
lift (HaskellName t) = [|HaskellName $(liftT t)|]
instance Lift DBName where
lift (DBName t) = [|DBName $(liftT t)|]
instance Lift FieldType where
lift (FTTypeCon Nothing t) = [|FTTypeCon Nothing $(liftT t)|]
lift (FTTypeCon (Just x) t) = [|FTTypeCon (Just $(liftT x)) $(liftT t)|]
lift (FTApp x y) = [|FTApp $(lift x) $(lift y)|]
lift (FTList x) = [|FTList $(lift 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 $(liftT x)|]
instance Lift PersistUpdate where
lift Assign = [|Assign|]
lift Add = [|Add|]
lift Subtract = [|Subtract|]
lift Multiply = [|Multiply|]
lift Divide = [|Divide|]
mkField :: MkPersistSettings -> EntityDef -> FieldDef -> Q (Con, Clause)
mkField mps et cd = do
let con = ForallC
[]
[EqualP (VarT $ mkName "typ") maybeTyp]
$ NormalC name []
bod <- lift cd
let cla = Clause
[ConP name []]
(NormalB bod)
[]
return (con, cla)
where
name = mkName $ unpack $ concat
[ unHaskellName $ entityHaskell et
, upperFirst $ unHaskellName $ fieldHaskell cd
]
maybeTyp =
if nullable (fieldAttrs cd) == Nullable ByMaybeAttr
then ConT ''Maybe `AppT` typ
else typ
typ =
case stripId $ fieldType cd of
Just ft ->
ConT ''KeyBackend
`AppT` (if mpsGeneric mps
then VarT $ mkName "backend"
else mpsBackend mps)
`AppT` genericDataType mps ft (VarT $ mkName "backend")
Nothing -> ftToType $ fieldType cd
ftToType :: FieldType -> Type
ftToType (FTTypeCon Nothing t) = ConT $ mkName $ unpack t
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 . unHaskellName . fieldHaskell)
$ entityFields def
let conName = mkName $ unpack $ unHaskellName $ entityHaskell def
typ = genericDataType mps (unHaskellName $ entityHaskell def) $ VarT $ mkName "backend"
toJSONI = InstanceD
[]
(ConT ''ToJSON `AppT` typ)
[toJSON']
toJSON' = FunD 'toJSON $ return $ Clause
[ConP conName $ map VarP xs]
(NormalB $ 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 = InstanceD
[]
(ConT ''FromJSON `AppT` typ)
[parseJSON']
parseJSON' = FunD 'parseJSON
[ Clause [ConP 'Object [VarP obj]]
(NormalB $ foldl'
(\x y -> InfixE (Just x) apE' (Just y))
(pureE `AppE` ConE conName)
pulls
)
[]
, Clause [WildP] (NormalB mzeroE) []
]
pulls = map toPull $ entityFields def
toPull f = InfixE
(Just $ VarE obj)
(if nullable (fieldAttrs f) == Nullable ByMaybeAttr then dotColonQE else dotColonE)
(Just $ AppE packE $ LitE $ StringL $ unpack $ unHaskellName $ fieldHaskell f)
return [toJSONI, fromJSONI]