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20 lines
515 B
Idris
20 lines
515 B
Idris
import Data.Vect
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%unbound_implicits off
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append : forall n, m, a . Vect n a -> Vect m a -> Vect (n + m) a
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append [] ys = ys
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append (x :: xs) ys = x :: append xs ys
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data Env : forall n . Vect n Type -> Type where
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ENil : Env []
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ECons : forall t, ts . t -> Env ts -> Env (t :: ts)
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-- fine because the only name used in bound, and it'll infer types for
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-- xs and its indices
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len : forall xs . Env xs -> Nat
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-- neither of these are fine
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len': Env xs -> Nat
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append' : Vect n a -> Vect m a -> Vect (n + m) a
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