Data.Extensible.Nullable

Documentation

coinclusion :: (Include ys xs, Generate ys) => Nullable (Membership xs) :* ys

The inverse of inclusion.

wrench :: (Generate ys, xs ⊆ ys) => (h :* xs) -> Nullable h :* ys

Extend a product and fill missing fields by Null.

retrench :: (Generate ys, xs ⊆ ys) => (h :| ys) -> Nullable ((:|) h) xs

Narrow the range of the sum, if possible.

newtype Nullable h x

Poly-kinded Maybe

Constructors

Nullable

Fields

getNullable :: Maybe (h x)

Instances

Wrapper k h => Wrapper k (Nullable k h)

Eq (h x) => Eq (Nullable k h x)

Ord (h x) => Ord (Nullable k h x)

Show (h x) => Show (Nullable k h x)

type Repr k (Nullable k h) x = Maybe (Repr k h x)

mapNullable :: (g x -> h y) -> Nullable g x -> Nullable h y

Apply a function to its content.