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https://github.com/idris-lang/Idris2.git
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49 lines
1.3 KiB
Idris
49 lines
1.3 KiB
Idris
import System
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import Data.Nat
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data ArrayData : Type -> Type where [external]
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-- We use `Integer` for indexing here instead of `Int` as in `Data.IOArray.Prims`
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%extern prim__newArray : forall a . Integer -> a -> PrimIO (ArrayData a)
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%extern prim__arrayGet : forall a . ArrayData a -> Integer -> PrimIO a
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%extern prim__arraySet : forall a . ArrayData a -> Integer -> a -> PrimIO ()
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record IOArray (n : Nat) a where
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constructor MkIOArray
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content : ArrayData a
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newArray : HasIO io => (n : Nat) -> a -> io (IOArray n a)
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newArray size v = pure (MkIOArray !(primIO (prim__newArray (cast size) v)))
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writeArray :
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HasIO io
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=> IOArray n a
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-> (m : Nat)
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-> {auto 0 lt : LT m n}
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-> a
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-> io ()
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writeArray arr pos el = primIO (prim__arraySet (content arr) (cast pos) el)
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readArray :
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HasIO io
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=> IOArray n a
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-> (m : Nat)
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-> {auto 0 lt : LT m n}
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-> io a
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readArray arr pos = primIO (prim__arrayGet (content arr) (cast pos))
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toList : {n : _} -> HasIO io => IOArray n a -> io (List a)
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toList arr = iter n reflexive []
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where
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iter : (m : Nat) -> (0 lte : LTE m n) -> List a -> io (List a)
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iter 0 _ acc = pure acc
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iter (S k) p acc = readArray arr k >>= \el => iter k (lteSuccLeft p) (el :: acc)
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main : IO ()
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main = do
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x <- newArray 20 ""
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writeArray x 11 "World"
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writeArray x 10 "Hello"
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printLn !(toList x)
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