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24 lines
670 B
Idris
24 lines
670 B
Idris
||| Additional functions about vectors
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module Data.Vect.Extra
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import Data.Vect
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import Data.Fin
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import Data.Vect.Elem
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||| Version of `map` with access to the current position
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public export
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mapWithPos : (f : Fin n -> a -> b) -> Vect n a -> Vect n b
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mapWithPos f [] = []
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mapWithPos f (x :: xs) = f 0 x :: mapWithPos (f . FS) xs
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||| Version of `map` with runtime-irrelevant information that the
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||| argument is an element of the vector
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public export
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mapWithElem : (xs : Vect n a)
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-> (f : (x : a) -> (0 pos : x `Elem` xs) -> b)
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-> Vect n b
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mapWithElem [] f = []
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mapWithElem (x :: xs) f
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= f x Here :: mapWithElem xs
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(\x,pos => f x (There pos))
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