Fcf.Utils

Miscellaneous families.

Documentation

data Error :: Symbol -> Exp a

Type-level error.

Instances

type Eval (Error msg :: a -> Type)

Defined in Fcf.Utils

type Eval (Error msg :: a -> Type) = (TypeError (Text msg) :: a)

data TError :: ErrorMessage -> Exp a

TypeError as a fcf.

Instances

type Eval (TError msg :: a -> Type)

Defined in Fcf.Utils

type Eval (TError msg :: a -> Type) = (TypeError msg :: a)

data Constraints :: [Constraint] -> Exp Constraint

Conjunction of a list of constraints.

Instances

type Eval (Constraints (a ': as) :: Constraint -> Type)

Defined in Fcf.Utils

type Eval (Constraints (a ': as) :: Constraint -> Type) = (a, Eval (Constraints as))

type Eval (Constraints ([] :: [Constraint]))

Defined in Fcf.Utils

type Eval (Constraints ([] :: [Constraint])) = ()

data TyEq :: a -> b -> Exp Bool

Type equality.

Instances

type Eval (TyEq a b :: Bool -> Type)

Defined in Fcf.Utils

type Eval (TyEq a b :: Bool -> Type)

type family Stuck :: a

A stuck type that can be used like a type-level undefined.

class IsBool (b :: Bool) where

Methods

_If :: (b ~ True => r) -> (b ~ False => r) -> r

Instances

IsBool False

Defined in Fcf.Utils

Methods

_If :: ((False ~ True) -> r) -> ((False ~ False) -> r) -> r

IsBool True

Defined in Fcf.Utils

Methods

_If :: ((True ~ True) -> r) -> ((True ~ False) -> r) -> r

From Data.Type.Bool.

type family If (cond :: Bool) (tru :: k) (fls :: k) :: k where ...

Type-level If. If True a b ==> a; If False a b ==> b

Equations

If True (tru :: k) (fls :: k) = tru

If False (tru :: k) (fls :: k) = fls