Data.Constraint.Deriving.ToInstance

Documentation

newtype ToInstance

A marker to tell the core plugin to convert a top-level Dict binding into an instance declaration.

Example:

type family FooFam a where
  FooFam Int = Int
  FooFam a   = Double

data FooSing a where
  FooInt   :: FooSing Int
  FooNoInt :: FooSing a

class FooClass a where
  fooSing :: FooSing a

newtype Bar a = Bar (FooFam a)

{-# ANN fooNum (ToInstance NoOverlap) #-}
fooNum :: forall a . Dict (Num (Bar a))
fooNum = mapDict (unsafeDerive Bar) $ case fooSing @a of
  FooInt   -> Dict
  FooNoInt -> Dict

Note:

• fooNum should be exported by the module (otherwise, it may be optimized-out before the core plugin pass);
• Constraints of the function become constraints of the new instance;
• The argument of Dict must be a single class (no constraint tuples or equality constraints);
• The instance is created in a core-to-core pass, so it does not exist for the type checker in the current module.

Constructors

ToInstance

Fields

• overlapMode :: OverlapMode

Instances

Eq ToInstance

Defined in Data.Constraint.Deriving.ToInstance

Methods

(==) :: ToInstance -> ToInstance -> Bool

(/=) :: ToInstance -> ToInstance -> Bool

Data ToInstance

Defined in Data.Constraint.Deriving.ToInstance

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> ToInstance -> c ToInstance

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c ToInstance

toConstr :: ToInstance -> Constr

dataTypeOf :: ToInstance -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c ToInstance)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c ToInstance)

gmapT :: (forall b. Data b => b -> b) -> ToInstance -> ToInstance

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> ToInstance -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> ToInstance -> r

gmapQ :: (forall d. Data d => d -> u) -> ToInstance -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> ToInstance -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> ToInstance -> m ToInstance

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> ToInstance -> m ToInstance

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> ToInstance -> m ToInstance

Read ToInstance

Defined in Data.Constraint.Deriving.ToInstance

Methods

readsPrec :: Int -> ReadS ToInstance

readList :: ReadS [ToInstance]

readPrec :: ReadPrec ToInstance

readListPrec :: ReadPrec [ToInstance]

Show ToInstance

Defined in Data.Constraint.Deriving.ToInstance

Methods

showsPrec :: Int -> ToInstance -> ShowS

show :: ToInstance -> String

showList :: [ToInstance] -> ShowS

data OverlapMode

Define the behavior for the instance selection. Mirrors OverlapMode, but does not have a SourceText field.

Constructors

NoOverlap

This instance must not overlap another NoOverlap instance. However, it may be overlapped by Overlapping instances, and it may overlap Overlappable instances.

Overlappable

Silently ignore this instance if you find a more specific one that matches the constraint you are trying to resolve

Overlapping

Silently ignore any more general instances that may be used to solve the constraint.

Overlaps

Equivalent to having both Overlapping and Overlappable flags.

Incoherent

Behave like Overlappable and Overlapping, and in addition pick an an arbitrary one if there are multiple matching candidates, and don't worry about later instantiation

Instances

Eq OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

(==) :: OverlapMode -> OverlapMode -> Bool

(/=) :: OverlapMode -> OverlapMode -> Bool

Data OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

gfoldl :: (forall d b. Data d => c (d -> b) -> d -> c b) -> (forall g. g -> c g) -> OverlapMode -> c OverlapMode

gunfold :: (forall b r. Data b => c (b -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c OverlapMode

toConstr :: OverlapMode -> Constr

dataTypeOf :: OverlapMode -> DataType

dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c OverlapMode)

dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c OverlapMode)

gmapT :: (forall b. Data b => b -> b) -> OverlapMode -> OverlapMode

gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> OverlapMode -> r

gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> OverlapMode -> r

gmapQ :: (forall d. Data d => d -> u) -> OverlapMode -> [u]

gmapQi :: Int -> (forall d. Data d => d -> u) -> OverlapMode -> u

gmapM :: Monad m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode

gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode

gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> OverlapMode -> m OverlapMode

Read OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

readsPrec :: Int -> ReadS OverlapMode

readList :: ReadS [OverlapMode]

readPrec :: ReadPrec OverlapMode

readListPrec :: ReadPrec [OverlapMode]

Show OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

showsPrec :: Int -> OverlapMode -> ShowS

show :: OverlapMode -> String

showList :: [OverlapMode] -> ShowS

Semigroup OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

(<>) :: OverlapMode -> OverlapMode -> OverlapMode

sconcat :: NonEmpty OverlapMode -> OverlapMode

stimes :: Integral b => b -> OverlapMode -> OverlapMode

Monoid OverlapMode

Defined in Data.Constraint.Deriving.CorePluginM

Methods

mempty :: OverlapMode

mappend :: OverlapMode -> OverlapMode -> OverlapMode

mconcat :: [OverlapMode] -> OverlapMode

toInstancePass :: CorePluginEnvRef -> CoreToDo

Run ToInstance plugin pass

type CorePluginEnvRef = IORef CorePluginEnv

Reference to the plugin environment variables.

initCorePluginEnv :: CoreM (IORef CorePluginEnv)

Init the CorePluginM environment and save it to IORef.