Safe Haskell | Safe-Infered |
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Darcs.Witnesses.Sealed
- data Sealed a where
- seal :: a x -> Sealed a
- unseal :: (forall x. a x -> b) -> Sealed a -> b
- mapSeal :: (forall x. a x -> b x) -> Sealed a -> Sealed b
- unsafeUnseal :: Sealed a -> a x
- unsafeUnsealFlipped :: FlippedSeal a y -> a x y
- unsafeUnseal2 :: Sealed2 a -> a x y
- data Sealed2 a where
- seal2 :: a x y -> Sealed2 a
- unseal2 :: (forall x y. a x y -> b) -> Sealed2 a -> b
- mapSeal2 :: (forall x y. a x y -> b x y) -> Sealed2 a -> Sealed2 b
- data FlippedSeal a y where
- FlippedSeal :: !(a x y) -> FlippedSeal a y
- flipSeal :: a x y -> FlippedSeal a y
- unsealFlipped :: (forall x y. a x y -> b) -> FlippedSeal a z -> b
- mapFlipped :: (forall x. a x y -> b x z) -> FlippedSeal a y -> FlippedSeal b z
- unsealM :: Monad m => m (Sealed a) -> (forall x. a x -> m b) -> m b
- liftSM :: Monad m => (forall x. a x -> b) -> m (Sealed a) -> m b
- class Gap w where
- data FreeLeft p
- unFreeLeft :: FreeLeft p -> Sealed (p x)
- data FreeRight p
- unFreeRight :: FreeRight p -> FlippedSeal p x
Documentation
data Sealed a where
unsafeUnseal :: Sealed a -> a x
unsafeUnsealFlipped :: FlippedSeal a y -> a x y
unsafeUnseal2 :: Sealed2 a -> a x y
data Sealed2 a where
data FlippedSeal a y where
Constructors
FlippedSeal :: !(a x y) -> FlippedSeal a y |
flipSeal :: a x y -> FlippedSeal a y
unsealFlipped :: (forall x y. a x y -> b) -> FlippedSeal a z -> b
mapFlipped :: (forall x. a x y -> b x z) -> FlippedSeal a y -> FlippedSeal b z
class Gap w where
Methods
emptyGap :: (forall x. p x x) -> w p
An empty Gap
, e.g. NilFL
or NilRL
freeGap :: (forall x y. p x y) -> w p
A Gap
constructed from a completely polymorphic value, for example the constructors
for primitive patches
joinGap :: (forall x y z. p x y -> q y z -> r x z) -> w p -> w q -> w r
Compose two Gap
values together in series, e.g. 'joinGap (+>+)' or 'joinGap (:>:)'
data FreeLeft p
'FreeLeft p' is 'forall x . exists y . p x y'
In other words the caller is free to specify the left witness,
and then the right witness is an existential.
Note that the order of the type constructors is important for ensuring
that y
is dependent on the x
that is supplied.
This is why Stepped
is needed, rather than writing the more obvious
'Sealed (Poly p)' which would notionally have the same quantification
of the type witnesses.
unFreeLeft :: FreeLeft p -> Sealed (p x)
Unwrap a FreeLeft
value
data FreeRight p
'FreeLeft p' is 'forall y . exists x . p x y'
In other words the caller is free to specify the right witness,
and then the left witness is an existential.
Note that the order of the type constructors is important for ensuring
that x
is dependent on the y
that is supplied.
unFreeRight :: FreeRight p -> FlippedSeal p x
Unwrap a FreeRight
value