Safe Haskell | None |
---|---|
Language | Haskell2010 |
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: 4.6.0.0
- data Nat
- data Symbol
- class KnownNat n
- natVal ∷ ∀ n proxy. KnownNat n ⇒ proxy n → Integer
- class KnownSymbol n
- symbolVal ∷ ∀ n proxy. KnownSymbol n ⇒ proxy n → String
- data SomeNat = ∀ n . KnownNat n ⇒ SomeNat (Proxy n)
- data SomeSymbol = ∀ n . KnownSymbol n ⇒ SomeSymbol (Proxy n)
- someNatVal ∷ Integer → Maybe SomeNat
- someSymbolVal ∷ String → SomeSymbol
- sameNat ∷ (KnownNat a, KnownNat b) ⇒ Proxy a → Proxy b → Maybe (a :~: b)
- sameSymbol ∷ (KnownSymbol a, KnownSymbol b) ⇒ Proxy a → Proxy b → Maybe (a :~: b)
- type (<=) x y = (x <=? y) ~ True
- type family m <=? n ∷ Bool
- type family m + n ∷ Nat
- type family m * n ∷ Nat
- type family m ^ n ∷ Nat
- type family m - n ∷ Nat
- type family CmpNat m n ∷ Ordering
- type family CmpSymbol m n ∷ Ordering
Kinds
Linking type and value level
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
natSing
class KnownSymbol n Source
This class gives the integer associated with a type-level symbol. There are instances of the class for every concrete literal: "hello", etc.
Since: 4.7.0.0
symbolSing
symbolVal ∷ ∀ n proxy. KnownSymbol n ⇒ proxy n → String Source
Since: 4.7.0.0
This type represents unknown type-level natural numbers.
data SomeSymbol Source
This type represents unknown type-level symbols.
∀ n . KnownSymbol n ⇒ SomeSymbol (Proxy n) | Since: 4.7.0.0 |
someNatVal ∷ Integer → Maybe SomeNat Source
Convert an integer into an unknown type-level natural.
Since: 4.7.0.0
someSymbolVal ∷ String → SomeSymbol Source
Convert a string into an unknown type-level symbol.
Since: 4.7.0.0
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
sameSymbol ∷ (KnownSymbol a, KnownSymbol b) ⇒ Proxy a → Proxy b → Maybe (a :~: b) Source
We either get evidence that this function was instantiated with the
same type-level symbols, or Nothing
.
Since: 4.7.0.0
Functions on type literals
type family m <=? n ∷ 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.