Idris2-boot/tests/idris2/interface001/IFace.idr
2019-06-24 17:36:55 +01:00

80 lines
1.6 KiB
Idris

module IFace
import Stuff
infixl 5 ==, /=
interface Eq b where
(==) : b -> b -> Bool
(/=) : b -> b -> Bool
Eq Nat where
(==) Z Z = True
(==) (S j) (S k) = j == k
(==) _ _ = False
(/=) x y = not (x == y)
[silly] Eq Nat where
(==) Z Z = False
(==) (S j) (S k) = j == k
(==) _ _ = True
(/=) x y = not (x == y)
Eq a => Eq (List a) where
(==) [] [] = True
(==) (x :: xs) (y :: ys) = x == y && xs == ys
(==) _ _ = False
(/=) x y = not (x == y)
(Eq a, Eq b) => Eq (a, b) where
(==) (x, y) (x', y') = x == x' && y == y'
[alsoSilly] Eq a => Eq (List a) where
(==) [] [] = False
(==) (x :: xs) (y :: ys) = x == y && xs == ys
(==) _ _ = True
(/=) x y = not (x == y)
test : ((Eq b, Eq b, Eq a), Eq b) => a -> a -> Bool
test x y = x == y
interface DecEq a where
decEq : (x : a) -> (y : a) -> Dec (x = y)
-- partial!
eqNat : (x : Nat) -> (y : Nat) -> Dec (x = y)
eqNat (S x) (S y)
= case eqNat x y of
Yes Refl => Yes Refl
eqNat Z Z = Yes Refl
DecEq Nat where
decEq = eqNat
data Vect : _ -> Type -> Type where
Nil : Vect Z a
(::) : a -> Vect k a -> Vect (S k) a
Eq a => Eq (Vect n a) where
(==) [] [] = True
(==) (x :: xs) (y :: ys) = x == y && xs == ys
(==) _ _ = False
(/=) xs ys = not (xs == ys)
v1 : DPair Nat (\n => Vect n Nat)
v1 = MkDPair _ [Z, S Z]
v2 : DPair Nat (\n => Vect n Nat)
v2 = MkDPair _ [Z, Z]
(DecEq a, {t : a} -> Eq (p t)) => Eq (DPair a p) where
(==) (MkDPair l r) (MkDPair l' r')
= case decEq l l' of
Yes Refl => r == r'
No _ => False