Strongweak.Strengthen

Strengthen class

class Weaken a => Strengthen a where

You may attempt to transform a Weak a to an a.

Laws:

• a === b -> strengthen a === strengthen b

• strengthen (weaken a) === Success a

We take Weaken as a superclass in order to maintain strong/weak type pair consistency. We choose this dependency direction because we treat the strong type as the "canonical" one, so Weaken is the more natural (and straightforward) class to define.

Instances should either handle an invariant, or decompose. See Strongweak for a discussion on this design.

Methods

strengthen :: Weak a -> Validation (NonEmpty StrengthenFail) a

Attempt to transform a weak value to its associated strong one.

Instances

Strengthen Int16

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Int16 -> Validation (NonEmpty StrengthenFail) Int16

Strengthen Int32

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Int32 -> Validation (NonEmpty StrengthenFail) Int32

Strengthen Int64

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Int64 -> Validation (NonEmpty StrengthenFail) Int64

Strengthen Int8

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Int8 -> Validation (NonEmpty StrengthenFail) Int8

Strengthen Word16

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Word16 -> Validation (NonEmpty StrengthenFail) Word16

Strengthen Word32

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Word32 -> Validation (NonEmpty StrengthenFail) Word32

Strengthen Word64

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Word64 -> Validation (NonEmpty StrengthenFail) Word64

Strengthen Word8

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak Word8 -> Validation (NonEmpty StrengthenFail) Word8

Strengthen a => Strengthen (Identity a)

Decomposer.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Identity a) -> Validation (NonEmpty StrengthenFail) (Identity a)

(Typeable a, Show a) => Strengthen (NonEmpty a)

Obtain a non-empty list by asserting non-emptiness of a plain list.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (NonEmpty a) -> Validation (NonEmpty StrengthenFail) (NonEmpty a)

Strengthen a => Strengthen (Maybe a)

Decomposer.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Maybe a) -> Validation (NonEmpty StrengthenFail) (Maybe a)

Strengthen a => Strengthen [a]

Decomposer. Strengthen every element in a list.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak [a] -> Validation (NonEmpty StrengthenFail) [a]

(Strengthen a, Strengthen b) => Strengthen (Either a b)

Decomposer.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Either a b) -> Validation (NonEmpty StrengthenFail) (Either a b)

(KnownNat n, Typeable a, Show a) => Strengthen (Vector n a)

Obtain a sized vector by asserting the size of a plain list.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Vector n a) -> Validation (NonEmpty StrengthenFail) (Vector n a)

(Strengthen a, Strengthen b) => Strengthen (a, b)

Decomposer.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (a, b) -> Validation (NonEmpty StrengthenFail) (a, b)

Strengthen a => Strengthen (Const a b)

Decomposer.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Const a b) -> Validation (NonEmpty StrengthenFail) (Const a b)

(Predicate p a, Typeable k, Typeable a, Show a) => Strengthen (Refined p a)

Obtain a refined type by applying its associated refinement.

Defined in Strongweak.Strengthen

Methods

strengthen :: Weak (Refined p a) -> Validation (NonEmpty StrengthenFail) (Refined p a)

Strengthen failures

data StrengthenFail

Strengthen failure data type. Don't use these constructors directly, use the existing helper functions.

Field indices are from 0 in the respective constructor. Field names are provided if present.

Constructors

StrengthenFailBase

Fields

• String

  weak type

• String

  strong type

• String

  weak value

• String

  msg

StrengthenFailField

Fields

• String

  weak datatype name

• String

  strong datatype name

• String

  weak constructor name

• String

  strong constructor name

• Natural

  weak field index

• (Maybe String)

  weak field name (if present)

• Natural

  strong field index

• (Maybe String)

  strong field name (if present)

• (NonEmpty StrengthenFail)

  failures

Instances

Show StrengthenFail

Defined in Strongweak.Strengthen

Methods

showsPrec :: Int -> StrengthenFail -> ShowS

show :: StrengthenFail -> String

showList :: [StrengthenFail] -> ShowS

Eq StrengthenFail

Defined in Strongweak.Strengthen

Methods

(==) :: StrengthenFail -> StrengthenFail -> Bool

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

Pretty StrengthenFail

Defined in Strongweak.Strengthen

Methods

pretty :: StrengthenFail -> Doc ann

prettyList :: [StrengthenFail] -> Doc ann

strengthenFailPretty :: NonEmpty StrengthenFail -> Doc a

strengthenFailBase :: forall s w. (Typeable w, Show w, Typeable s) => w -> String -> Validation (NonEmpty StrengthenFail) s

Restrengthening

restrengthen :: (Strengthen a, Weaken a) => a -> Validation (NonEmpty StrengthenFail) a

Weaken a strong value, then strengthen it again.

Potentially useful if you have previously used unsafeStrengthen and now wish to check the invariants. For example:

>>> restrengthen $ unsafeStrengthen @(Vector 2 Natural) [0]
Failure ...

Helpers

strengthenBounded :: forall b n. (Integral b, Bounded b, Show b, Typeable b, Integral n, Show n, Typeable n) => n -> Validation (NonEmpty StrengthenFail) b

Re-exports

type family Weak a :: Type

The type to weaken to.

Instances

type Weak Int16

Defined in Strongweak.Weaken

type Weak Int16 = Integer

type Weak Int32

Defined in Strongweak.Weaken

type Weak Int32 = Integer

type Weak Int64

Defined in Strongweak.Weaken

type Weak Int64 = Integer

type Weak Int8

Defined in Strongweak.Weaken

type Weak Int8 = Integer

type Weak Word16

Defined in Strongweak.Weaken

type Weak Word16 = Natural

type Weak Word32

Defined in Strongweak.Weaken

type Weak Word32 = Natural

type Weak Word64

Defined in Strongweak.Weaken

type Weak Word64 = Natural

type Weak Word8

Defined in Strongweak.Weaken

type Weak Word8 = Natural

type Weak (Identity a)

Defined in Strongweak.Weaken

type Weak (Identity a) = Identity (Weak a)

type Weak (NonEmpty a)

Defined in Strongweak.Weaken

type Weak (NonEmpty a) = [a]

type Weak (Maybe a)

Defined in Strongweak.Weaken

type Weak (Maybe a) = Maybe (Weak a)

type Weak [a]

Defined in Strongweak.Weaken

type Weak [a] = [Weak a]

type Weak (Either a b)

Defined in Strongweak.Weaken

type Weak (Either a b) = Either (Weak a) (Weak b)

type Weak (Vector n a)

Defined in Strongweak.Weaken

type Weak (Vector n a) = [a]

type Weak (a, b)

Defined in Strongweak.Weaken

type Weak (a, b) = (Weak a, Weak b)

type Weak (Const a b)

Defined in Strongweak.Weaken

type Weak (Const a b) = Const (Weak a) b

type Weak (Refined p a)

Defined in Strongweak.Weaken

type Weak (Refined p a) = a