Data.Extensible.Inclusion

Inclusion

type (⊆) xs ys = Include ys xs

Unicode alias for Include

type Include ys = Forall (Member ys)

ys contains xs

inclusion :: forall xs ys. Include ys xs => Membership ys :* xs

Reify the inclusion of type level sets.

shrink :: xs ⊆ ys => (h :* ys) -> h :* xs

O(m log n) Select some elements.

spread :: xs ⊆ ys => (h :| xs) -> h :| ys

O(log n) Embed to a larger union.

Key-value

type IncludeAssoc ys = Forall (Associated ys)

Similar to Include, but this focuses on keys.

class Associated xs t

Minimal complete definition

getAssociation

Instances

Associate k k1 k2 v xs => Associated (Assoc k k) xs ((:>) k k k v)

inclusionAssoc :: forall xs ys. IncludeAssoc ys xs => Membership ys :* xs

Reify the inclusion of type level sets.

shrinkAssoc :: IncludeAssoc ys xs => (h :* ys) -> h :* xs

O(m log n) Select some elements.

spreadAssoc :: IncludeAssoc ys xs => (h :| xs) -> h :| ys

O(log n) Embed to a larger union.

Inverse

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.

data Nullable h x

Poly-kinded Maybe

Constructors

Null

Eine (h x)

Instances

Typeable ((k -> *) -> k -> *) (Nullable k)

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

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

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

nullable :: r -> (h x -> r) -> Nullable h x -> r

Destruct Nullable.

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

Apply a function to its content.