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34 lines
661 B
Plaintext
34 lines
661 B
Plaintext
data Bool : Type where
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False : Bool
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True : Bool
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not : Bool -> Bool
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not False = True
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not True = False
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data Nat : Type where
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Z : Nat
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S : Nat -> Nat
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plus : Nat -> Nat -> Nat
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plus Z y = y
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plus (S k) y = S (plus k y)
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data Vect : ? -> Type -> Type where
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Nil : Vect Z a
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Cons : a -> Vect k a -> Vect (S k) a
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data Fin : Nat -> Type where
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FZ : Fin (S k)
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FS : Fin k -> Fin (S k)
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lookup : Fin n -> Vect n a -> a
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lookup FZ (Cons x xs) = x
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lookup (FS k) (Cons x xs) = lookup k xs
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append : Vect n a -> Vect m a -> Vect (plus n m) a
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append xs ys
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= case xs of
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Nil => ys
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Cons z zs => Cons z (append zs ys)
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