Copyright | (c) The University of Glasgow 2003 |
---|---|
License | BSD-style (see the file libraries/base/LICENSE) |
Maintainer | libraries@haskell.org |
Stability | experimental |
Portability | portable |
Safe Haskell | Trustworthy |
Language | Haskell2010 |
Abstract syntax definitions for Template Haskell.
Synopsis
- sequenceQ :: forall m. Monad m => forall a. [m a] -> m [a]
- mkName :: String -> Name
- mkNameG_v :: String -> String -> String -> Name
- mkNameG_d :: String -> String -> String -> Name
- mkNameG_tc :: String -> String -> String -> Name
- mkNameL :: String -> Uniq -> Name
- mkNameS :: String -> Name
- unTypeCode :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => Code m a -> m Exp
- mkModName :: String -> ModName
- unsafeCodeCoerce :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m Exp -> Code m a
- liftString :: Quote m => String -> m Exp
- class Lift (t :: TYPE r) where
- class Monad m => Quote m where
- data Exp
- = VarE Name
- | ConE Name
- | LitE Lit
- | AppE Exp Exp
- | AppTypeE Exp Type
- | InfixE (Maybe Exp) Exp (Maybe Exp)
- | UInfixE Exp Exp Exp
- | ParensE Exp
- | LamE [Pat] Exp
- | LamCaseE [Match]
- | TupE [Maybe Exp]
- | UnboxedTupE [Maybe Exp]
- | UnboxedSumE Exp SumAlt SumArity
- | CondE Exp Exp Exp
- | MultiIfE [(Guard, Exp)]
- | LetE [Dec] Exp
- | CaseE Exp [Match]
- | DoE (Maybe ModName) [Stmt]
- | MDoE (Maybe ModName) [Stmt]
- | CompE [Stmt]
- | ArithSeqE Range
- | ListE [Exp]
- | SigE Exp Type
- | RecConE Name [FieldExp]
- | RecUpdE Exp [FieldExp]
- | StaticE Exp
- | UnboundVarE Name
- | LabelE String
- | ImplicitParamVarE String
- | GetFieldE Exp String
- | ProjectionE (NonEmpty String)
- data Match = Match Pat Body [Dec]
- data Clause = Clause [Pat] Body [Dec]
- newtype Q a = Q {}
- data Pat
- data Stmt
- data Con
- data Type
- = ForallT [TyVarBndr Specificity] Cxt Type
- | ForallVisT [TyVarBndr ()] Type
- | AppT Type Type
- | AppKindT Type Kind
- | SigT Type Kind
- | VarT Name
- | ConT Name
- | PromotedT Name
- | InfixT Type Name Type
- | UInfixT Type Name Type
- | ParensT Type
- | TupleT Int
- | UnboxedTupleT Int
- | UnboxedSumT SumArity
- | ArrowT
- | MulArrowT
- | EqualityT
- | ListT
- | PromotedTupleT Int
- | PromotedNilT
- | PromotedConsT
- | StarT
- | ConstraintT
- | LitT TyLit
- | WildCardT
- | ImplicitParamT String Type
- data Dec
- = FunD Name [Clause]
- | ValD Pat Body [Dec]
- | DataD Cxt Name [TyVarBndr ()] (Maybe Kind) [Con] [DerivClause]
- | NewtypeD Cxt Name [TyVarBndr ()] (Maybe Kind) Con [DerivClause]
- | TySynD Name [TyVarBndr ()] Type
- | ClassD Cxt Name [TyVarBndr ()] [FunDep] [Dec]
- | InstanceD (Maybe Overlap) Cxt Type [Dec]
- | SigD Name Type
- | KiSigD Name Kind
- | ForeignD Foreign
- | InfixD Fixity Name
- | PragmaD Pragma
- | DataFamilyD Name [TyVarBndr ()] (Maybe Kind)
- | DataInstD Cxt (Maybe [TyVarBndr ()]) Type (Maybe Kind) [Con] [DerivClause]
- | NewtypeInstD Cxt (Maybe [TyVarBndr ()]) Type (Maybe Kind) Con [DerivClause]
- | TySynInstD TySynEqn
- | OpenTypeFamilyD TypeFamilyHead
- | ClosedTypeFamilyD TypeFamilyHead [TySynEqn]
- | RoleAnnotD Name [Role]
- | StandaloneDerivD (Maybe DerivStrategy) Cxt Type
- | DefaultSigD Name Type
- | PatSynD Name PatSynArgs PatSynDir Pat
- | PatSynSigD Name PatSynType
- | ImplicitParamBindD String Exp
- type BangType = (Bang, Type)
- type VarBangType = (Name, Bang, Type)
- type FieldExp = (Name, Exp)
- type FieldPat = (Name, Pat)
- data Name = Name OccName NameFlavour
- data FunDep = FunDep [Name] [Name]
- type Pred = Type
- data RuleBndr
- data TySynEqn = TySynEqn (Maybe [TyVarBndr ()]) Type Type
- data InjectivityAnn = InjectivityAnn Name [Name]
- type Kind = Type
- data Overlap
- data DerivClause = DerivClause (Maybe DerivStrategy) Cxt
- data DerivStrategy
- newtype Code m (a :: TYPE (r :: RuntimeRep)) = Code {
- examineCode :: m (TExp a)
- newtype ModName = ModName String
- addCorePlugin :: String -> Q ()
- addDependentFile :: FilePath -> Q ()
- addForeignFile :: ForeignSrcLang -> String -> Q ()
- addForeignFilePath :: ForeignSrcLang -> FilePath -> Q ()
- addForeignSource :: ForeignSrcLang -> String -> Q ()
- addModFinalizer :: Q () -> Q ()
- addTempFile :: String -> Q FilePath
- addTopDecls :: [Dec] -> Q ()
- badIO :: String -> IO a
- bindCode :: forall m a (r :: RuntimeRep) (b :: TYPE r). Monad m => m a -> (a -> Code m b) -> Code m b
- bindCode_ :: forall m a (r :: RuntimeRep) (b :: TYPE r). Monad m => m a -> Code m b -> Code m b
- cmpEq :: Ordering -> Bool
- compareBytes :: Bytes -> Bytes -> Ordering
- counter :: IORef Uniq
- dataToExpQ :: (Quote m, Data a) => (forall b. Data b => b -> Maybe (m Exp)) -> a -> m Exp
- dataToPatQ :: (Quote m, Data a) => (forall b. Data b => b -> Maybe (m Pat)) -> a -> m Pat
- dataToQa :: forall m a k q. (Quote m, Data a) => (Name -> k) -> (Lit -> m q) -> (k -> [m q] -> m q) -> (forall b. Data b => b -> Maybe (m q)) -> a -> m q
- defaultFixity :: Fixity
- eqBytes :: Bytes -> Bytes -> Bool
- extsEnabled :: Q [Extension]
- falseName :: Name
- getDoc :: DocLoc -> Q (Maybe String)
- getQ :: Typeable a => Q (Maybe a)
- hoistCode :: forall m n (r :: RuntimeRep) (a :: TYPE r). Monad m => (forall x. m x -> n x) -> Code m a -> Code n a
- isExtEnabled :: Extension -> Q Bool
- isInstance :: Name -> [Type] -> Q Bool
- joinCode :: forall m (r :: RuntimeRep) (a :: TYPE r). Monad m => m (Code m a) -> Code m a
- justName :: Name
- leftName :: Name
- liftCode :: forall (r :: RuntimeRep) (a :: TYPE r) m. m (TExp a) -> Code m a
- liftData :: (Quote m, Data a) => a -> m Exp
- location :: Q Loc
- lookupName :: Bool -> String -> Q (Maybe Name)
- lookupTypeName :: String -> Q (Maybe Name)
- lookupValueName :: String -> Q (Maybe Name)
- manyName :: Name
- maxPrecedence :: Int
- memcmp :: Ptr a -> Ptr b -> CSize -> IO CInt
- mkNameG :: NameSpace -> String -> String -> String -> Name
- mkNameU :: String -> Uniq -> Name
- mkOccName :: String -> OccName
- mkPkgName :: String -> PkgName
- mk_tup_name :: Int -> NameSpace -> Bool -> Name
- modString :: ModName -> String
- nameBase :: Name -> String
- nameModule :: Name -> Maybe String
- namePackage :: Name -> Maybe String
- nameSpace :: Name -> Maybe NameSpace
- newNameIO :: String -> IO Name
- nonemptyName :: Name
- nothingName :: Name
- occString :: OccName -> String
- oneName :: Name
- pkgString :: PkgName -> String
- putDoc :: DocLoc -> String -> Q ()
- putQ :: Typeable a => a -> Q ()
- recover :: Q a -> Q a -> Q a
- reify :: Name -> Q Info
- reifyAnnotations :: Data a => AnnLookup -> Q [a]
- reifyConStrictness :: Name -> Q [DecidedStrictness]
- reifyFixity :: Name -> Q (Maybe Fixity)
- reifyInstances :: Name -> [Type] -> Q [InstanceDec]
- reifyModule :: Module -> Q ModuleInfo
- reifyRoles :: Name -> Q [Role]
- reifyType :: Name -> Q Type
- report :: Bool -> String -> Q ()
- reportError :: String -> Q ()
- reportWarning :: String -> Q ()
- rightName :: Name
- runIO :: IO a -> Q a
- runQ :: Quasi m => Q a -> m a
- showName :: Name -> String
- showName' :: NameIs -> Name -> String
- thenCmp :: Ordering -> Ordering -> Ordering
- trueName :: Name
- tupleDataName :: Int -> Name
- tupleTypeName :: Int -> Name
- unTypeQ :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m (TExp a) -> m Exp
- unboxedSumDataName :: SumAlt -> SumArity -> Name
- unboxedSumTypeName :: SumArity -> Name
- unboxedTupleDataName :: Int -> Name
- unboxedTupleTypeName :: Int -> Name
- unsafeTExpCoerce :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m Exp -> m (TExp a)
- data AnnLookup
- data AnnTarget
- type Arity = Int
- data Bang = Bang SourceUnpackedness SourceStrictness
- data Body
- data Bytes = Bytes {
- bytesPtr :: ForeignPtr Word8
- bytesOffset :: Word
- bytesSize :: Word
- data Callconv
- = CCall
- | StdCall
- | CApi
- | Prim
- | JavaScript
- type CharPos = (Int, Int)
- type Cxt = [Pred]
- data DecidedStrictness
- data DocLoc
- data FamilyResultSig
- data Fixity = Fixity Int FixityDirection
- data FixityDirection
- data Foreign
- data Guard
- data Info
- data Inline
- type InstanceDec = Dec
- data Lit
- data Loc = Loc {}
- data Module = Module PkgName ModName
- data ModuleInfo = ModuleInfo [Module]
- data NameFlavour
- data NameIs
- data NameSpace
- newtype OccName = OccName String
- type ParentName = Name
- data PatSynArgs
- = PrefixPatSyn [Name]
- | InfixPatSyn Name Name
- | RecordPatSyn [Name]
- data PatSynDir
- type PatSynType = Type
- data Phases
- newtype PkgName = PkgName String
- data Pragma
- class (MonadIO m, MonadFail m) => Quasi m where
- qNewName :: String -> m Name
- qReport :: Bool -> String -> m ()
- qRecover :: m a -> m a -> m a
- qLookupName :: Bool -> String -> m (Maybe Name)
- qReify :: Name -> m Info
- qReifyFixity :: Name -> m (Maybe Fixity)
- qReifyType :: Name -> m Type
- qReifyInstances :: Name -> [Type] -> m [Dec]
- qReifyRoles :: Name -> m [Role]
- qReifyAnnotations :: Data a => AnnLookup -> m [a]
- qReifyModule :: Module -> m ModuleInfo
- qReifyConStrictness :: Name -> m [DecidedStrictness]
- qLocation :: m Loc
- qRunIO :: IO a -> m a
- qAddDependentFile :: FilePath -> m ()
- qAddTempFile :: String -> m FilePath
- qAddTopDecls :: [Dec] -> m ()
- qAddForeignFilePath :: ForeignSrcLang -> String -> m ()
- qAddModFinalizer :: Q () -> m ()
- qAddCorePlugin :: String -> m ()
- qGetQ :: Typeable a => m (Maybe a)
- qPutQ :: Typeable a => a -> m ()
- qIsExtEnabled :: Extension -> m Bool
- qExtsEnabled :: m [Extension]
- qPutDoc :: DocLoc -> String -> m ()
- qGetDoc :: DocLoc -> m (Maybe String)
- data Range
- data Role
- data RuleMatch
- data Safety
- = Unsafe
- | Safe
- | Interruptible
- data SourceStrictness
- data SourceUnpackedness
- data Specificity
- type Strict = Bang
- type StrictType = BangType
- type SumAlt = Int
- type SumArity = Int
- newtype TExp (a :: TYPE (r :: RuntimeRep)) = TExp {}
- data TyLit
- data TyVarBndr flag
- data TypeFamilyHead = TypeFamilyHead Name [TyVarBndr ()] FamilyResultSig (Maybe InjectivityAnn)
- type Uniq = Integer
- type Unlifted = Bool
- type VarStrictType = VarBangType
- module Language.Haskell.TH.LanguageExtensions
- data ForeignSrcLang
Documentation
mkName :: String -> Name Source #
Generate a capturable name. Occurrences of such names will be resolved according to the Haskell scoping rules at the occurrence site.
For example:
f = [| pi + $(varE (mkName "pi")) |] ... g = let pi = 3 in $f
In this case, g
is desugared to
g = Prelude.pi + 3
Note that mkName
may be used with qualified names:
mkName "Prelude.pi"
See also dyn
for a useful combinator. The above example could
be rewritten using dyn
as
f = [| pi + $(dyn "pi") |]
unTypeCode :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => Code m a -> m Exp Source #
Extract the untyped representation from the typed representation
unsafeCodeCoerce :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m Exp -> Code m a Source #
Unsafely convert an untyped code representation into a typed code representation.
class Lift (t :: TYPE r) where Source #
A Lift
instance can have any of its values turned into a Template
Haskell expression. This is needed when a value used within a Template
Haskell quotation is bound outside the Oxford brackets ([| ... |]
or
[|| ... ||]
) but not at the top level. As an example:
add1 :: Int -> Q (TExp Int) add1 x = [|| x + 1 ||]
Template Haskell has no way of knowing what value x
will take on at
splice-time, so it requires the type of x
to be an instance of Lift
.
A Lift
instance must satisfy $(lift x) ≡ x
and $$(liftTyped x) ≡ x
for all x
, where $(...)
and $$(...)
are Template Haskell splices.
It is additionally expected that
.lift
x ≡ unTypeQ
(liftTyped
x)
Lift
instances can be derived automatically by use of the -XDeriveLift
GHC language extension:
{-# LANGUAGE DeriveLift #-} module Foo where import Language.Haskell.TH.Syntax data Bar a = Bar1 a (Bar a) | Bar2 String deriving Lift
Levity-polymorphic since template-haskell-2.16.0.0.
lift :: Quote m => t -> m Exp Source #
Turn a value into a Template Haskell expression, suitable for use in a splice.
liftTyped :: Quote m => t -> Code m t Source #
Turn a value into a Template Haskell typed expression, suitable for use in a typed splice.
Since: template-haskell-2.16.0.0
Instances
Lift Addr# Source # | Produces an Since: template-haskell-2.16.0.0 |
Lift Double# Source # | Since: template-haskell-2.16.0.0 |
Lift Float# Source # | Since: template-haskell-2.16.0.0 |
Lift Int# Source # | Since: template-haskell-2.16.0.0 |
Lift Void Source # | Since: template-haskell-2.15.0.0 |
Lift Int16 Source # | |
Lift Int32 Source # | |
Lift Int64 Source # | |
Lift Int8 Source # | |
Lift Word16 Source # | |
Lift Word32 Source # | |
Lift Word64 Source # | |
Lift Word8 Source # | |
Lift Integer Source # | |
Lift Natural Source # | |
Lift () Source # | |
Lift Bool Source # | |
Lift Char Source # | |
Lift Double Source # | |
Lift Float Source # | |
Lift Int Source # | |
Lift Word Source # | |
Lift Char# Source # | Since: template-haskell-2.16.0.0 |
Lift Word# Source # | Since: template-haskell-2.16.0.0 |
Integral a => Lift (Ratio a :: Type) Source # | |
Lift a => Lift (NonEmpty a :: Type) Source # | Since: template-haskell-2.15.0.0 |
Lift a => Lift (Maybe a :: Type) Source # | |
Lift a => Lift ([a] :: Type) Source # | |
(Lift a, Lift b) => Lift (Either a b :: Type) Source # | |
(Lift a, Lift b) => Lift ((a, b) :: Type) Source # | |
(Lift a, Lift b, Lift c) => Lift ((a, b, c) :: Type) Source # | |
(Lift a, Lift b, Lift c, Lift d) => Lift ((a, b, c, d) :: Type) Source # | |
(Lift a, Lift b, Lift c, Lift d, Lift e) => Lift ((a, b, c, d, e) :: Type) Source # | |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f) => Lift ((a, b, c, d, e, f) :: Type) Source # | |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f, Lift g) => Lift ((a, b, c, d, e, f, g) :: Type) Source # | |
Lift (# #) Source # | Since: template-haskell-2.16.0.0 |
Lift a => Lift ((# a #) :: TYPE ('TupleRep '['BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b) => Lift ((# a | b #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b) => Lift ((# a, b #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c) => Lift ((# a | b | c #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c) => Lift ((# a, b, c #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d) => Lift ((# a | b | c | d #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d) => Lift ((# a, b, c, d #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e) => Lift ((# a | b | c | d | e #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e) => Lift ((# a, b, c, d, e #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f) => Lift ((# a | b | c | d | e | f #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f) => Lift ((# a, b, c, d, e, f #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f, Lift g) => Lift ((# a | b | c | d | e | f | g #) :: TYPE ('SumRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f, Lift g) => Lift ((# a, b, c, d, e, f, g #) :: TYPE ('TupleRep '['BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted, 'BoxedRep 'Lifted])) Source # | Since: template-haskell-2.16.0.0 |
class Monad m => Quote m where Source #
The Quote
class implements the minimal interface which is necessary for
desugaring quotations.
- The
Monad m
superclass is needed to stitch together the different AST fragments. newName
is used when desugaring binding structures such as lambdas to generate fresh names.
Therefore the type of an untyped quotation in GHC is `Quote m => m Exp`
For many years the type of a quotation was fixed to be `Q Exp` but by
more precisely specifying the minimal interface it enables the Exp
to
be extracted purely from the quotation without interacting with Q
.
newName :: String -> m Name Source #
Generate a fresh name, which cannot be captured.
For example, this:
f = $(do nm1 <- newName "x" let nm2 =mkName
"x" return (LamE
[VarP
nm1] (LamE [VarP nm2] (VarE
nm1))) )
will produce the splice
f = \x0 -> \x -> x0
In particular, the occurrence VarE nm1
refers to the binding VarP nm1
,
and is not captured by the binding VarP nm2
.
Although names generated by newName
cannot be captured, they can
capture other names. For example, this:
g = $(do nm1 <- newName "x" let nm2 = mkName "x" return (LamE [VarP nm2] (LamE [VarP nm1] (VarE nm2))) )
will produce the splice
g = \x -> \x0 -> x0
since the occurrence VarE nm2
is captured by the innermost binding
of x
, namely VarP nm1
.
VarE Name | { x } |
ConE Name | data T1 = C1 t1 t2; p = {C1} e1 e2 |
LitE Lit | { 5 or 'c'} |
AppE Exp Exp | { f x } |
AppTypeE Exp Type | { f @Int } |
InfixE (Maybe Exp) Exp (Maybe Exp) | {x + y} or {(x+)} or {(+ x)} or {(+)} |
UInfixE Exp Exp Exp | {x + y} |
ParensE Exp | { (e) } |
LamE [Pat] Exp | { \ p1 p2 -> e } |
LamCaseE [Match] | { \case m1; m2 } |
TupE [Maybe Exp] | { (e1,e2) } The (1,) translates to TupE [Just (LitE (IntegerL 1)),Nothing] |
UnboxedTupE [Maybe Exp] | { (# e1,e2 #) } The (# 'c', #) translates to UnboxedTupE [Just (LitE (CharL 'c')),Nothing] |
UnboxedSumE Exp SumAlt SumArity | { (#|e|#) } |
CondE Exp Exp Exp | { if e1 then e2 else e3 } |
MultiIfE [(Guard, Exp)] | { if | g1 -> e1 | g2 -> e2 } |
LetE [Dec] Exp | { let { x=e1; y=e2 } in e3 } |
CaseE Exp [Match] | { case e of m1; m2 } |
DoE (Maybe ModName) [Stmt] |
|
MDoE (Maybe ModName) [Stmt] |
|
CompE [Stmt] | { [ (x,y) | x <- xs, y <- ys ] } The result expression of the comprehension is
the last of the E.g. translation: [ f x | x <- xs ] CompE [BindS (VarP x) (VarE xs), NoBindS (AppE (VarE f) (VarE x))] |
ArithSeqE Range | { [ 1 ,2 .. 10 ] } |
ListE [Exp] | { [1,2,3] } |
SigE Exp Type | { e :: t } |
RecConE Name [FieldExp] | { T { x = y, z = w } } |
RecUpdE Exp [FieldExp] | { (f x) { z = w } } |
StaticE Exp | { static e } |
UnboundVarE Name | { _x } This is used for holes or unresolved identifiers in AST quotes. Note that it could either have a variable name or constructor name. |
LabelE String |
|
ImplicitParamVarE String |
|
GetFieldE Exp String |
|
ProjectionE (NonEmpty String) |
|
Instances
Instances
Data Match Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Match -> c Match Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Match Source # toConstr :: Match -> Constr Source # dataTypeOf :: Match -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Match) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Match) Source # gmapT :: (forall b. Data b => b -> b) -> Match -> Match Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Match -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Match -> r Source # gmapQ :: (forall d. Data d => d -> u) -> Match -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> Match -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Match -> m Match Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Match -> m Match Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Match -> m Match Source # | |
Generic Match Source # | |
Show Match Source # | |
Eq Match Source # | |
Ord Match Source # | |
Defined in Language.Haskell.TH.Syntax | |
Ppr Match Source # | |
type Rep Match Source # | |
Defined in Language.Haskell.TH.Syntax type Rep Match = D1 ('MetaData "Match" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "Match" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Pat) :*: (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Body) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Dec])))) |
Instances
Data Clause Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Clause -> c Clause Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Clause Source # toConstr :: Clause -> Constr Source # dataTypeOf :: Clause -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Clause) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Clause) Source # gmapT :: (forall b. Data b => b -> b) -> Clause -> Clause Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Clause -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Clause -> r Source # gmapQ :: (forall d. Data d => d -> u) -> Clause -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> Clause -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Clause -> m Clause Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Clause -> m Clause Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Clause -> m Clause Source # | |
Generic Clause Source # | |
Show Clause Source # | |
Eq Clause Source # | |
Ord Clause Source # | |
Defined in Language.Haskell.TH.Syntax | |
Ppr Clause Source # | |
type Rep Clause Source # | |
Defined in Language.Haskell.TH.Syntax type Rep Clause = D1 ('MetaData "Clause" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "Clause" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Pat]) :*: (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Body) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Dec])))) |
Instances
Pattern in Haskell given in {}
LitP Lit | { 5 or 'c' } |
VarP Name | { x } |
TupP [Pat] | { (p1,p2) } |
UnboxedTupP [Pat] | { (# p1,p2 #) } |
UnboxedSumP Pat SumAlt SumArity | { (#|p|#) } |
ConP Name [Type] [Pat] | data T1 = C1 t1 t2; {C1 @ty1 p1 p2} = e |
InfixP Pat Name Pat | foo ({x :+ y}) = e |
UInfixP Pat Name Pat | foo ({x :+ y}) = e |
ParensP Pat | {(p)} |
TildeP Pat | { ~p } |
BangP Pat | { !p } |
AsP Name Pat | { x @ p } |
WildP | { _ } |
RecP Name [FieldPat] | f (Pt { pointx = x }) = g x |
ListP [Pat] | { [1,2,3] } |
SigP Pat Type | { p :: t } |
ViewP Exp Pat | { e -> p } |
Instances
BindS Pat Exp | p <- e |
LetS [Dec] | { let { x=e1; y=e2 } } |
NoBindS Exp | e |
ParS [[Stmt]] |
|
RecS [Stmt] | rec { s1; s2 } |
Instances
A single data constructor.
The constructors for Con
can roughly be divided up into two categories:
those for constructors with "vanilla" syntax (NormalC
, RecC
, and
InfixC
), and those for constructors with GADT syntax (GadtC
and
RecGadtC
). The ForallC
constructor, which quantifies additional type
variables and class contexts, can surround either variety of constructor.
However, the type variables that it quantifies are different depending
on what constructor syntax is used:
- If a
ForallC
surrounds a constructor with vanilla syntax, then theForallC
will only quantify existential type variables. For example:
data Foo a = forall b. MkFoo a b
In MkFoo
, ForallC
will quantify b
, but not a
.
- If a
ForallC
surrounds a constructor with GADT syntax, then theForallC
will quantify all type variables used in the constructor. For example:
data Bar a b where MkBar :: (a ~ b) => c -> MkBar a b
In MkBar
, ForallC
will quantify a
, b
, and c
.
NormalC Name [BangType] | C Int a |
RecC Name [VarBangType] | C { v :: Int, w :: a } |
InfixC BangType Name BangType | Int :+ a |
ForallC [TyVarBndr Specificity] Cxt Con | forall a. Eq a => C [a] |
GadtC [Name] [BangType] Type | C :: a -> b -> T b Int |
RecGadtC [Name] [VarBangType] Type | C :: { v :: Int } -> T b Int |
Instances
ForallT [TyVarBndr Specificity] Cxt Type | forall <vars>. <ctxt> => <type> |
ForallVisT [TyVarBndr ()] Type | forall <vars> -> <type> |
AppT Type Type | T a b |
AppKindT Type Kind | T @k t |
SigT Type Kind | t :: k |
VarT Name | a |
ConT Name | T |
PromotedT Name | 'T |
InfixT Type Name Type | T + T |
UInfixT Type Name Type | T + T |
ParensT Type | (T) |
TupleT Int | (,), (,,), etc. |
UnboxedTupleT Int | (#,#), (#,,#), etc. |
UnboxedSumT SumArity | (#|#), (#||#), etc. |
ArrowT | -> |
MulArrowT | FUN |
EqualityT | ~ |
ListT | [] |
PromotedTupleT Int | '(), '(,), '(,,), etc. |
PromotedNilT | '[] |
PromotedConsT | (':) |
StarT | * |
ConstraintT | Constraint |
LitT TyLit | 0,1,2, etc. |
WildCardT | _ |
ImplicitParamT String Type | ?x :: t |
Instances
FunD Name [Clause] | { f p1 p2 = b where decs } |
ValD Pat Body [Dec] | { p = b where decs } |
DataD Cxt Name [TyVarBndr ()] (Maybe Kind) [Con] [DerivClause] | { data Cxt x => T x = A x | B (T x) deriving (Z,W) deriving stock Eq } |
NewtypeD Cxt Name [TyVarBndr ()] (Maybe Kind) Con [DerivClause] | { newtype Cxt x => T x = A (B x) deriving (Z,W Q) deriving stock Eq } |
TySynD Name [TyVarBndr ()] Type | { type T x = (x,x) } |
ClassD Cxt Name [TyVarBndr ()] [FunDep] [Dec] | { class Eq a => Ord a where ds } |
InstanceD (Maybe Overlap) Cxt Type [Dec] | { instance {-# OVERLAPS #-} Show w => Show [w] where ds } |
SigD Name Type | { length :: [a] -> Int } |
KiSigD Name Kind | { type TypeRep :: k -> Type } |
ForeignD Foreign | { foreign import ... } { foreign export ... } |
InfixD Fixity Name | { infix 3 foo } |
PragmaD | pragmas |
| |
DataFamilyD | data families (may also appear in [Dec] of |
DataInstD Cxt (Maybe [TyVarBndr ()]) Type (Maybe Kind) [Con] [DerivClause] | { data instance Cxt x => T [x] = A x | B (T x) deriving (Z,W) deriving stock Eq } |
NewtypeInstD Cxt (Maybe [TyVarBndr ()]) Type (Maybe Kind) Con [DerivClause] | { newtype instance Cxt x => T [x] = A (B x) deriving (Z,W) deriving stock Eq } |
TySynInstD TySynEqn | { type instance ... } |
OpenTypeFamilyD | open type families (may also appear in [Dec] of |
| |
ClosedTypeFamilyD TypeFamilyHead [TySynEqn] | { type family F a b = (r :: *) | r -> a where ... } |
RoleAnnotD Name [Role] | { type role T nominal representational } |
StandaloneDerivD (Maybe DerivStrategy) Cxt Type | { deriving stock instance Ord a => Ord (Foo a) } |
DefaultSigD Name Type | { default size :: Data a => a -> Int } |
PatSynD | Pattern Synonyms |
| |
PatSynSigD Name PatSynType | A pattern synonym's type signature. |
ImplicitParamBindD String Exp | { ?x = expr } Implicit parameter binding declaration. Can only be used in let and where clauses which consist entirely of implicit bindings. |
Instances
An abstract type representing names in the syntax tree.
Name
s can be constructed in several ways, which come with different
name-capture guarantees (see Language.Haskell.TH.Syntax for
an explanation of name capture):
- the built-in syntax
'f
and''T
can be used to construct names, The expression'f
gives aName
which refers to the valuef
currently in scope, and''T
gives aName
which refers to the typeT
currently in scope. These names can never be captured. lookupValueName
andlookupTypeName
are similar to'f
and''T
respectively, but theName
s are looked up at the point where the current splice is being run. These names can never be captured.newName
monadically generates a new name, which can never be captured.mkName
generates a capturable name.
Names constructed using newName
and mkName
may be used in bindings
(such as let x = ...
or x -> ...
), but names constructed using
lookupValueName
, lookupTypeName
, 'f
, ''T
may not.
Instances
Data Name Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Name -> c Name Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Name Source # toConstr :: Name -> Constr Source # dataTypeOf :: Name -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Name) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Name) Source # gmapT :: (forall b. Data b => b -> b) -> Name -> Name Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Name -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Name -> r Source # gmapQ :: (forall d. Data d => d -> u) -> Name -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> Name -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Name -> m Name Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Name -> m Name Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Name -> m Name Source # | |
Generic Name Source # | |
Show Name Source # | |
Eq Name Source # | |
Ord Name Source # | |
Defined in Language.Haskell.TH.Syntax | |
Ppr Name Source # | |
type Rep Name Source # | |
Defined in Language.Haskell.TH.Syntax type Rep Name = D1 ('MetaData "Name" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "Name" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 OccName) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 NameFlavour))) |
Instances
Data FunDep Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> FunDep -> c FunDep Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c FunDep Source # toConstr :: FunDep -> Constr Source # dataTypeOf :: FunDep -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c FunDep) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c FunDep) Source # gmapT :: (forall b. Data b => b -> b) -> FunDep -> FunDep Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> FunDep -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> FunDep -> r Source # gmapQ :: (forall d. Data d => d -> u) -> FunDep -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> FunDep -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> FunDep -> m FunDep Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> FunDep -> m FunDep Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> FunDep -> m FunDep Source # | |
Generic FunDep Source # | |
Show FunDep Source # | |
Eq FunDep Source # | |
Ord FunDep Source # | |
Defined in Language.Haskell.TH.Syntax | |
Ppr FunDep Source # | |
type Rep FunDep Source # | |
Defined in Language.Haskell.TH.Syntax type Rep FunDep = D1 ('MetaData "FunDep" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "FunDep" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Name]) :*: S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 [Name]))) |
Since the advent of ConstraintKinds
, constraints are really just types.
Equality constraints use the EqualityT
constructor. Constraints may also
be tuples of other constraints.
Instances
One equation of a type family instance or closed type family. The arguments are the left-hand-side type and the right-hand-side result.
For instance, if you had the following type family:
type family Foo (a :: k) :: k where forall k (a :: k). Foo @k a = a
The Foo @k a = a
equation would be represented as follows:
TySynEqn
(Just
[PlainTV
k,KindedTV
a (VarT
k)]) (AppT
(AppKindT
(ConT
''Foo) (VarT
k)) (VarT
a)) (VarT
a)
Instances
data InjectivityAnn Source #
Injectivity annotation
Instances
To avoid duplication between kinds and types, they
are defined to be the same. Naturally, you would never
have a type be StarT
and you would never have a kind
be SigT
, but many of the other constructors are shared.
Note that the kind Bool
is denoted with ConT
, not
PromotedT
. Similarly, tuple kinds are made with TupleT
,
not PromotedTupleT
.
Varieties of allowed instance overlap.
Overlappable | May be overlapped by more specific instances |
Overlapping | May overlap a more general instance |
Overlaps | Both |
Incoherent | Both |
Instances
Data Overlap Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> Overlap -> c Overlap Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c Overlap Source # toConstr :: Overlap -> Constr Source # dataTypeOf :: Overlap -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c Overlap) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c Overlap) Source # gmapT :: (forall b. Data b => b -> b) -> Overlap -> Overlap Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Overlap -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Overlap -> r Source # gmapQ :: (forall d. Data d => d -> u) -> Overlap -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> Overlap -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Overlap -> m Overlap Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Overlap -> m Overlap Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Overlap -> m Overlap Source # | |
Generic Overlap Source # | |
Show Overlap Source # | |
Eq Overlap Source # | |
Ord Overlap Source # | |
Defined in Language.Haskell.TH.Syntax | |
type Rep Overlap Source # | |
Defined in Language.Haskell.TH.Syntax type Rep Overlap = D1 ('MetaData "Overlap" "Language.Haskell.TH.Syntax" "template-haskell" 'False) ((C1 ('MetaCons "Overlappable" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Overlapping" 'PrefixI 'False) (U1 :: Type -> Type)) :+: (C1 ('MetaCons "Overlaps" 'PrefixI 'False) (U1 :: Type -> Type) :+: C1 ('MetaCons "Incoherent" 'PrefixI 'False) (U1 :: Type -> Type))) |
data DerivClause Source #
A single deriving
clause at the end of a datatype.
DerivClause (Maybe DerivStrategy) Cxt | { deriving stock (Eq, Ord) } |
Instances
data DerivStrategy Source #
What the user explicitly requests when deriving an instance.
StockStrategy | A "standard" derived instance |
AnyclassStrategy | -XDeriveAnyClass |
NewtypeStrategy | -XGeneralizedNewtypeDeriving |
ViaStrategy Type | -XDerivingVia |
Instances
newtype Code m (a :: TYPE (r :: RuntimeRep)) Source #
Code | |
|
Instances
Data ModName Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ModName -> c ModName Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ModName Source # toConstr :: ModName -> Constr Source # dataTypeOf :: ModName -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ModName) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ModName) Source # gmapT :: (forall b. Data b => b -> b) -> ModName -> ModName Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ModName -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ModName -> r Source # gmapQ :: (forall d. Data d => d -> u) -> ModName -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> ModName -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> ModName -> m ModName Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ModName -> m ModName Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ModName -> m ModName Source # | |
Generic ModName Source # | |
Show ModName Source # | |
Eq ModName Source # | |
Ord ModName Source # | |
Defined in Language.Haskell.TH.Syntax | |
type Rep ModName Source # | |
Defined in Language.Haskell.TH.Syntax |
addCorePlugin :: String -> Q () Source #
Adds a core plugin to the compilation pipeline.
addCorePlugin m
has almost the same effect as passing -fplugin=m
to ghc
in the command line. The major difference is that the plugin module m
must not belong to the current package. When TH executes, it is too late
to tell the compiler that we needed to compile first a plugin module in the
current package.
addDependentFile :: FilePath -> Q () Source #
Record external files that runIO is using (dependent upon). The compiler can then recognize that it should re-compile the Haskell file when an external file changes.
Expects an absolute file path.
Notes:
- ghc -M does not know about these dependencies - it does not execute TH.
- The dependency is based on file content, not a modification time
addForeignFile :: ForeignSrcLang -> String -> Q () Source #
Deprecated: Use addForeignSource
instead
addForeignFilePath :: ForeignSrcLang -> FilePath -> Q () Source #
Same as addForeignSource
, but expects to receive a path pointing to the
foreign file instead of a String
of its contents. Consider using this in
conjunction with addTempFile
.
This is a good alternative to addForeignSource
when you are trying to
directly link in an object file.
addForeignSource :: ForeignSrcLang -> String -> Q () Source #
Emit a foreign file which will be compiled and linked to the object for the current module. Currently only languages that can be compiled with the C compiler are supported, and the flags passed as part of -optc will be also applied to the C compiler invocation that will compile them.
Note that for non-C languages (for example C++) extern C
directives
must be used to get symbols that we can access from Haskell.
To get better errors, it is recommended to use #line pragmas when emitting C files, e.g.
{-# LANGUAGE CPP #-} ... addForeignSource LangC $ unlines [ "#line " ++ show (691 + 1) ++ " " ++ show "libraries/template-haskell/./Language/Haskell/TH/Syntax.hs" , ... ]
addModFinalizer :: Q () -> Q () Source #
Add a finalizer that will run in the Q monad after the current module has been type checked. This only makes sense when run within a top-level splice.
The finalizer is given the local type environment at the splice point. Thus
reify
is able to find the local definitions when executed inside the
finalizer.
addTempFile :: String -> Q FilePath Source #
Obtain a temporary file path with the given suffix. The compiler will delete this file after compilation.
addTopDecls :: [Dec] -> Q () Source #
Add additional top-level declarations. The added declarations will be type checked along with the current declaration group.
bindCode :: forall m a (r :: RuntimeRep) (b :: TYPE r). Monad m => m a -> (a -> Code m b) -> Code m b Source #
Variant of (>>=) which allows effectful computations to be injected into code generation.
bindCode_ :: forall m a (r :: RuntimeRep) (b :: TYPE r). Monad m => m a -> Code m b -> Code m b Source #
Variant of (>>) which allows effectful computations to be injected into code generation.
dataToExpQ :: (Quote m, Data a) => (forall b. Data b => b -> Maybe (m Exp)) -> a -> m Exp Source #
dataToExpQ
converts a value to a Exp
representation of the
same value, in the SYB style. It is generalized to take a function
override type-specific cases; see liftData
for a more commonly
used variant.
dataToPatQ :: (Quote m, Data a) => (forall b. Data b => b -> Maybe (m Pat)) -> a -> m Pat Source #
dataToPatQ
converts a value to a Pat
representation of the same
value, in the SYB style. It takes a function to handle type-specific cases,
alternatively, pass const Nothing
to get default behavior.
dataToQa :: forall m a k q. (Quote m, Data a) => (Name -> k) -> (Lit -> m q) -> (k -> [m q] -> m q) -> (forall b. Data b => b -> Maybe (m q)) -> a -> m q Source #
dataToQa
is an internal utility function for constructing generic
conversion functions from types with Data
instances to various
quasi-quoting representations. See the source of dataToExpQ
and
dataToPatQ
for two example usages: mkCon
, mkLit
and appQ
are overloadable to account for different syntax for
expressions and patterns; antiQ
allows you to override type-specific
cases, a common usage is just const Nothing
, which results in
no overloading.
defaultFixity :: Fixity Source #
Default fixity: infixl 9
extsEnabled :: Q [Extension] Source #
List all enabled language extensions.
getDoc :: DocLoc -> Q (Maybe String) Source #
Retreives the Haddock documentation at the specified location, if one
exists.
It can be used to read documentation on things defined outside of the current
module, provided that those modules were compiled with the -haddock
flag.
getQ :: Typeable a => Q (Maybe a) Source #
Get state from the Q
monad. Note that the state is local to the
Haskell module in which the Template Haskell expression is executed.
hoistCode :: forall m n (r :: RuntimeRep) (a :: TYPE r). Monad m => (forall x. m x -> n x) -> Code m a -> Code n a Source #
Modify the ambient monad used during code generation. For example, you
can use hoistCode
to handle a state effect:
handleState :: Code (StateT Int Q) a -> Code Q a
handleState = hoistCode (flip runState 0)
isExtEnabled :: Extension -> Q Bool Source #
Determine whether the given language extension is enabled in the Q
monad.
isInstance :: Name -> [Type] -> Q Bool Source #
Is the list of instances returned by reifyInstances
nonempty?
joinCode :: forall m (r :: RuntimeRep) (a :: TYPE r). Monad m => m (Code m a) -> Code m a Source #
A useful combinator for embedding monadic actions into Code
myCode :: ... => Code m a
myCode = joinCode $ do
x <- someSideEffect
return (makeCodeWith x)
liftCode :: forall (r :: RuntimeRep) (a :: TYPE r) m. m (TExp a) -> Code m a Source #
Lift a monadic action producing code into the typed Code
representation
lookupTypeName :: String -> Q (Maybe Name) Source #
Look up the given name in the (type namespace of the) current splice's scope. See Language.Haskell.TH.Syntax for more details.
lookupValueName :: String -> Q (Maybe Name) Source #
Look up the given name in the (value namespace of the) current splice's scope. See Language.Haskell.TH.Syntax for more details.
maxPrecedence :: Int Source #
Highest allowed operator precedence for Fixity
constructor (answer: 9)
mkNameG :: NameSpace -> String -> String -> String -> Name Source #
Used for 'x etc, but not available to the programmer
nameBase :: Name -> String Source #
The name without its module prefix.
Examples
>>>
nameBase ''Data.Either.Either
"Either">>>
nameBase (mkName "foo")
"foo">>>
nameBase (mkName "Module.foo")
"foo"
nameModule :: Name -> Maybe String Source #
Module prefix of a name, if it exists.
Examples
>>>
nameModule ''Data.Either.Either
Just "Data.Either">>>
nameModule (mkName "foo")
Nothing>>>
nameModule (mkName "Module.foo")
Just "Module"
namePackage :: Name -> Maybe String Source #
A name's package, if it exists.
Examples
>>>
namePackage ''Data.Either.Either
Just "base">>>
namePackage (mkName "foo")
Nothing>>>
namePackage (mkName "Module.foo")
Nothing
nameSpace :: Name -> Maybe NameSpace Source #
Returns whether a name represents an occurrence of a top-level variable
(VarName
), data constructor (DataName
), type constructor, or type class
(TcClsName
). If we can't be sure, it returns Nothing
.
Examples
>>>
nameSpace 'Prelude.id
Just VarName>>>
nameSpace (mkName "id")
Nothing -- only works for top-level variable names>>>
nameSpace 'Data.Maybe.Just
Just DataName>>>
nameSpace ''Data.Maybe.Maybe
Just TcClsName>>>
nameSpace ''Data.Ord.Ord
Just TcClsName
nonemptyName :: Name Source #
nothingName :: Name Source #
putDoc :: DocLoc -> String -> Q () Source #
Add Haddock documentation to the specified location. This will overwrite
any documentation at the location if it already exists. This will reify the
specified name, so it must be in scope when you call it. If you want to add
documentation to something that you are currently splicing, you can use
addModFinalizer
e.g.
do let nm = mkName "x" addModFinalizer $ putDoc (DeclDoc nm) "Hello" [d| $(varP nm) = 42 |]
The helper functions withDecDoc
and withDecsDoc
will do this for you, as
will the funD_doc
and other _doc
combinators.
You most likely want to have the -haddock
flag turned on when using this.
Adding documentation to anything outside of the current module will cause an
error.
putQ :: Typeable a => a -> Q () Source #
Replace the state in the Q
monad. Note that the state is local to the
Haskell module in which the Template Haskell expression is executed.
Recover from errors raised by reportError
or fail
.
reify :: Name -> Q Info Source #
reify
looks up information about the Name
.
It is sometimes useful to construct the argument name using lookupTypeName
or lookupValueName
to ensure that we are reifying from the right namespace. For instance, in this context:
data D = D
which D
does reify (mkName "D")
return information about? (Answer: D
-the-type, but don't rely on it.)
To ensure we get information about D
-the-value, use lookupValueName
:
do Just nm <- lookupValueName "D" reify nm
and to get information about D
-the-type, use lookupTypeName
.
reifyAnnotations :: Data a => AnnLookup -> Q [a] Source #
reifyAnnotations target
returns the list of annotations
associated with target
. Only the annotations that are
appropriately typed is returned. So if you have Int
and String
annotations for the same target, you have to call this function twice.
reifyConStrictness :: Name -> Q [DecidedStrictness] Source #
reifyConStrictness nm
looks up the strictness information for the fields
of the constructor with the name nm
. Note that the strictness information
that reifyConStrictness
returns may not correspond to what is written in
the source code. For example, in the following data declaration:
data Pair a = Pair a a
reifyConStrictness
would return [
under most
circumstances, but it would return DecidedLazy
, DecidedLazy][
if the
DecidedStrict
, DecidedStrict]-XStrictData
language extension was enabled.
reifyFixity :: Name -> Q (Maybe Fixity) Source #
reifyFixity nm
attempts to find a fixity declaration for nm
. For
example, if the function foo
has the fixity declaration infixr 7 foo
, then
reifyFixity 'foo
would return
. If the function
Just
(Fixity
7 InfixR
)bar
does not have a fixity declaration, then reifyFixity 'bar
returns
Nothing
, so you may assume bar
has defaultFixity
.
reifyInstances :: Name -> [Type] -> Q [InstanceDec] Source #
reifyInstances nm tys
returns a list of visible instances of nm tys
. That is,
if nm
is the name of a type class, then all instances of this class at the types tys
are returned. Alternatively, if nm
is the name of a data family or type family,
all instances of this family at the types tys
are returned.
Note that this is a "shallow" test; the declarations returned merely have
instance heads which unify with nm tys
, they need not actually be satisfiable.
reifyInstances ''Eq [
contains theTupleT
2 `AppT
`ConT
''A `AppT
`ConT
''B ]instance (Eq a, Eq b) => Eq (a, b)
regardless of whetherA
andB
themselves implementEq
reifyInstances ''Show [
produces every available instance ofVarT
(mkName
"a") ]Eq
There is one edge case: reifyInstances ''Typeable tys
currently always
produces an empty list (no matter what tys
are given).
reifyModule :: Module -> Q ModuleInfo Source #
reifyModule mod
looks up information about module mod
. To
look up the current module, call this function with the return
value of thisModule
.
reifyRoles :: Name -> Q [Role] Source #
reifyRoles nm
returns the list of roles associated with the parameters of
the tycon nm
. Fails if nm
cannot be found or is not a tycon.
The returned list should never contain InferR
.
reifyType :: Name -> Q Type Source #
reifyType nm
attempts to find the type or kind of nm
. For example,
reifyType 'not
returns Bool -> Bool
, and
reifyType ''Bool
returns Type
.
This works even if there's no explicit signature and the type or kind is inferred.
report :: Bool -> String -> Q () Source #
Deprecated: Use reportError or reportWarning instead
Report an error (True) or warning (False),
but carry on; use fail
to stop.
reportError :: String -> Q () Source #
Report an error to the user, but allow the current splice's computation to carry on. To abort the computation, use fail
.
reportWarning :: String -> Q () Source #
Report a warning to the user, and carry on.
The runIO
function lets you run an I/O computation in the Q
monad.
Take care: you are guaranteed the ordering of calls to runIO
within
a single Q
computation, but not about the order in which splices are run.
Note: for various murky reasons, stdout and stderr handles are not necessarily flushed when the compiler finishes running, so you should flush them yourself.
tupleDataName :: Int -> Name Source #
Tuple data constructor
tupleTypeName :: Int -> Name Source #
Tuple type constructor
unTypeQ :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m (TExp a) -> m Exp Source #
Discard the type annotation and produce a plain Template Haskell expression
Levity-polymorphic since template-haskell-2.16.0.0.
unboxedSumTypeName :: SumArity -> Name Source #
Unboxed sum type constructor
unboxedTupleDataName :: Int -> Name Source #
Unboxed tuple data constructor
unboxedTupleTypeName :: Int -> Name Source #
Unboxed tuple type constructor
unsafeTExpCoerce :: forall (r :: RuntimeRep) (a :: TYPE r) m. Quote m => m Exp -> m (TExp a) Source #
Annotate the Template Haskell expression with a type
This is unsafe because GHC cannot check for you that the expression really does have the type you claim it has.
Levity-polymorphic since template-haskell-2.16.0.0.
Annotation target for reifyAnnotations
Instances
Data AnnLookup Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AnnLookup -> c AnnLookup Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AnnLookup Source # toConstr :: AnnLookup -> Constr Source # dataTypeOf :: AnnLookup -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AnnLookup) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AnnLookup) Source # gmapT :: (forall b. Data b => b -> b) -> AnnLookup -> AnnLookup Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AnnLookup -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AnnLookup -> r Source # gmapQ :: (forall d. Data d => d -> u) -> AnnLookup -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> AnnLookup -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> AnnLookup -> m AnnLookup Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> AnnLookup -> m AnnLookup Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> AnnLookup -> m AnnLookup Source # | |
Generic AnnLookup Source # | |
Show AnnLookup Source # | |
Eq AnnLookup Source # | |
Ord AnnLookup Source # | |
Defined in Language.Haskell.TH.Syntax | |
type Rep AnnLookup Source # | |
Defined in Language.Haskell.TH.Syntax type Rep AnnLookup = D1 ('MetaData "AnnLookup" "Language.Haskell.TH.Syntax" "template-haskell" 'False) (C1 ('MetaCons "AnnLookupModule" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Module)) :+: C1 ('MetaCons "AnnLookupName" 'PrefixI 'False) (S1 ('MetaSel ('Nothing :: Maybe Symbol) 'NoSourceUnpackedness 'NoSourceStrictness 'DecidedLazy) (Rec0 Name))) |
Instances
Data AnnTarget Source # | |
Defined in Language.Haskell.TH.Syntax gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> AnnTarget -> c AnnTarget Source # gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c AnnTarget Source # toConstr :: AnnTarget -> Constr Source # dataTypeOf :: AnnTarget -> DataType Source # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c AnnTarget) Source # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c AnnTarget) Source # gmapT :: (forall b. Data b => b -> b) -> AnnTarget -> AnnTarget Source # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> AnnTarget -> r Source # gmapQr :: forall r r'. (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> AnnTarget -> r Source # gmapQ :: (forall d. Data d => d -> u) -> AnnTarget -> [u] Source # gmapQi :: Int -> (forall d. Data d => d -> u) -> AnnTarget -> u Source # gmapM :: Monad m => (forall d. Data d => d -> m d) -> AnnTarget -> m AnnTarget Source # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> AnnTarget -> m AnnTarget Source # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> AnnTarget -> m AnnTarget Source # | |
Generic AnnTarget Source # | |