Safe Haskell	None
Language	Haskell2010

TypeFun.Data.Maybe

Synopsis

type family MaybeCase (a :: Maybe k) (nothing :: r) (just :: k -> r) :: r where ...
type family NothingToConstr (a :: Maybe k) (c :: Constraint) :: Constraint where ...
type family JustToConstr (a :: Maybe k) (c :: Constraint) :: Constraint where ...
type family CatMaybes (l :: [Maybe k]) :: [k] where ...
type family FromJust (a :: Maybe k) :: k where ...

Documentation

type family MaybeCase (a :: Maybe k) (nothing :: r) (just :: k -> r) :: r where ... Source #

Equations

MaybeCase 'Nothing nothing just = nothing
MaybeCase ('Just k) nothing just = just k

Equations

NothingToConstr 'Nothing c = c
NothingToConstr ('Just a) c = ()

type family JustToConstr (a :: Maybe k) (c :: Constraint) :: Constraint where ... Source #

Equations

JustToConstr 'Nothing c = ()
JustToConstr ('Just a) c = c

type family CatMaybes (l :: [Maybe k]) :: [k] where ... Source #

Like catMaybes for type lists

Equations

CatMaybes '[] = '[]
CatMaybes ('Just a ': as) = a ': CatMaybes as
CatMaybes ('Nothing ': as) = CatMaybes as

type family FromJust (a :: Maybe k) :: k where ... Source #

Equations