Safe Haskell	None
Language	Haskell2010

Language.Haskell.TH.Lift

Contents

Orphan instances

Synopsis

deriveLift :: Name -> Q [Dec]
deriveLiftMany :: [Name] -> Q [Dec]
deriveLift' :: [Role] -> Info -> Q [Dec]
deriveLiftMany' :: [([Role], Info)] -> Q [Dec]
makeLift :: Name -> Q Exp
makeLift' :: Info -> Q Exp
class Lift t where
- lift :: t -> Q Exp

Documentation

deriveLift :: Name -> Q [Dec] Source #

Derive Lift instances for the given datatype.

deriveLiftMany :: [Name] -> Q [Dec] Source #

Derive Lift instances for many datatypes.

deriveLift' :: [Role] -> Info -> Q [Dec] Source #

Obtain Info values through a custom reification function. This is useful when generating instances for datatypes that have not yet been declared.

deriveLiftMany' :: [([Role], Info)] -> Q [Dec] Source #

makeLift :: Name -> Q Exp Source #

Generates a lambda expresson which behaves like lift (without requiring a Lift instance). Example:

newtype Fix f = In { out :: f (Fix f) }

instance Lift (f (Fix f)) => Lift (Fix f) where
  lift = $(makeLift ''Fix)

makeLift' :: Info -> Q Exp Source #

Like makeLift, but using a custom reification function.

class Lift t where #

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 ([| ... |]) but not at the top level. As an example:

add1 :: Int -> Q Exp
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 for all x, where $(...) is a Template Haskell splice.

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

Minimal complete definition

Nothing

Methods

lift :: t -> Q Exp #

Turn a value into a Template Haskell expression, suitable for use in a splice.

Instances

Lift Bool
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Bool -> Q Exp #
Lift Char
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Char -> Q Exp #
Lift Double
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Double -> Q Exp #
Lift Float
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Float -> Q Exp #
Lift Int
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Int -> Q Exp #
Lift Int8
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Int8 -> Q Exp #
Lift Int16
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Int16 -> Q Exp #
Lift Int32
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Int32 -> Q Exp #
Lift Int64
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Int64 -> Q Exp #
Lift Integer
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Integer -> Q Exp #
Lift Natural
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Natural -> Q Exp #
Lift Word
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Word -> Q Exp #
Lift Word8
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Word8 -> Q Exp #
Lift Word16
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Word16 -> Q Exp #
Lift Word32
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Word32 -> Q Exp #
Lift Word64
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Word64 -> Q Exp #
Lift Name Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: Name -> Q Exp #
Lift ()
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: () -> Q Exp #
Lift ModName Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: ModName -> Q Exp #
Lift PkgName Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: PkgName -> Q Exp #
Lift OccName Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: OccName -> Q Exp #
Lift NameFlavour Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: NameFlavour -> Q Exp #
Lift NameSpace Source #
Instance details Defined in Language.Haskell.TH.Lift Methods lift :: NameSpace -> Q Exp #
Lift a => Lift [a]
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: [a] -> Q Exp #
Lift a => Lift (Maybe a)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Maybe a -> Q Exp #
Integral a => Lift (Ratio a)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Ratio a -> Q Exp #
(Lift a, Lift b) => Lift (Either a b)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: Either a b -> Q Exp #
(Lift a, Lift b) => Lift (a, b)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b) -> Q Exp #
(Lift a, Lift b, Lift c) => Lift (a, b, c)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b, c) -> Q Exp #
(Lift a, Lift b, Lift c, Lift d) => Lift (a, b, c, d)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b, c, d) -> Q Exp #
(Lift a, Lift b, Lift c, Lift d, Lift e) => Lift (a, b, c, d, e)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b, c, d, e) -> Q Exp #
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f) => Lift (a, b, c, d, e, f)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b, c, d, e, f) -> Q Exp #
(Lift a, Lift b, Lift c, Lift d, Lift e, Lift f, Lift g) => Lift (a, b, c, d, e, f, g)
Instance details Defined in Language.Haskell.TH.Syntax Methods lift :: (a, b, c, d, e, f, g) -> Q Exp #

Orphan instances

Lift Name Source #
Instance details Methods lift :: Name -> Q Exp #
Lift ModName Source #
Instance details Methods lift :: ModName -> Q Exp #
Lift PkgName Source #
Instance details Methods lift :: PkgName -> Q Exp #
Lift OccName Source #
Instance details Methods lift :: OccName -> Q Exp #
Lift NameFlavour Source #
Instance details Methods lift :: NameFlavour -> Q Exp #
Lift NameSpace Source #
Instance details Methods lift :: NameSpace -> Q Exp #