| Safe Haskell | Trustworthy |
|---|---|
| Language | Haskell2010 |
GHC.TypeNats
Description
This module is an internal GHC module. It declares the constants used in the implementation of type-level natural numbers. The programmer interface for working with type-level naturals should be defined in a separate library.
Since: 4.10.0.0
- data Nat :: *
- class KnownNat (n :: Nat)
- natVal :: forall n proxy. KnownNat n => proxy n -> Natural
- natVal' :: forall n. KnownNat n => Proxy# n -> Natural
- data SomeNat = KnownNat n => SomeNat (Proxy n)
- someNatVal :: Natural -> SomeNat
- sameNat :: (KnownNat a, KnownNat b) => Proxy a -> Proxy b -> Maybe (a :~: b)
- type (<=) x y = (x <=? y) ~ True
- type family (m :: Nat) <=? (n :: Nat) :: Bool
- type family (m :: Nat) + (n :: Nat) :: Nat
- type family (m :: Nat) * (n :: Nat) :: Nat
- type family (m :: Nat) ^ (n :: Nat) :: Nat
- type family (m :: Nat) - (n :: Nat) :: Nat
- type family CmpNat (m :: Nat) (n :: Nat) :: Ordering
Nat Kind
(Kind) This is the kind of type-level natural numbers.
Linking type and value level
class KnownNat (n :: Nat) Source #
This class gives the integer associated with a type-level natural. There are instances of the class for every concrete literal: 0, 1, 2, etc.
Since: 4.7.0.0
Minimal complete definition
natSing
This type represents unknown type-level natural numbers.
Since: 4.10.0.0
someNatVal :: Natural -> SomeNat Source #
Convert an integer into an unknown type-level natural.
Since: 4.10.0.0
sameNat :: (KnownNat a, KnownNat b) => Proxy a -> Proxy b -> Maybe (a :~: b) Source #
We either get evidence that this function was instantiated with the
same type-level numbers, or Nothing.
Since: 4.7.0.0
Functions on type literals
type (<=) x y = (x <=? y) ~ True infix 4 Source #
Comparison of type-level naturals, as a constraint.
type family (m :: Nat) <=? (n :: Nat) :: Bool infix 4 Source #
Comparison of type-level naturals, as a function.
NOTE: The functionality for this function should be subsumed
by CmpNat, so this might go away in the future.
Please let us know, if you encounter discrepancies between the two.