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https://github.com/idris-lang/Idris2.git
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dbdf7dab3d
Following a fairly detailed discussion on slack, the feeling is generally that it's better to have a single interface. While precision is nice, it doesn't appear to buy us anything here. If that turns out to be wrong, or limiting somehow, we can revisit it later. Also: - it's easier for backend authors if the type of IO operations is slightly less restrictive. For example, if it's in HasIO, that limits alternative implementations, which might be awkward for some alternative back ends. - it's one less extra detail to learn. This is minor, but there needs to be a clear advantage if there's more detail to learn. - It is difficult to think of an underlying type that can't have a Monad instance (I have personally never encountered one - if they turns out to exist, again, we can revisit!)
81 lines
2.4 KiB
Idris
81 lines
2.4 KiB
Idris
module Data.IOArray
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import Data.IOArray.Prims
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import Data.List
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export
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record IOArray elem where
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constructor MkIOArray
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maxSize : Int
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content : ArrayData (Maybe elem)
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export
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max : IOArray elem -> Int
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max = maxSize
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export
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newArray : HasIO io => Int -> io (IOArray elem)
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newArray size
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= pure (MkIOArray size !(primIO (prim__newArray size Nothing)))
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export
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writeArray : HasIO io => IOArray elem -> Int -> elem -> io ()
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writeArray arr pos el
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= if pos < 0 || pos >= max arr
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then pure ()
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else primIO (prim__arraySet (content arr) pos (Just el))
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export
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readArray : HasIO io => IOArray elem -> Int -> io (Maybe elem)
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readArray arr pos
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= if pos < 0 || pos >= max arr
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then pure Nothing
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else primIO (prim__arrayGet (content arr) pos)
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-- Make a new array of the given size with the elements copied from the
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-- other array
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export
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newArrayCopy : HasIO io =>
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(newsize : Int) -> IOArray elem -> io (IOArray elem)
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newArrayCopy newsize arr
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= do let newsize' = if newsize < max arr then max arr else newsize
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arr' <- newArray newsize'
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copyFrom (content arr) (content arr') (max arr - 1)
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pure arr'
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where
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copyFrom : ArrayData (Maybe elem) ->
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ArrayData (Maybe elem) ->
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Int -> io ()
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copyFrom old new pos
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= if pos < 0
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then pure ()
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else do el <- primIO $ prim__arrayGet old pos
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primIO $ prim__arraySet new pos el
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assert_total (copyFrom old new (pos - 1))
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export
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toList : HasIO io => IOArray elem -> io (List (Maybe elem))
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toList arr = iter 0 (max arr) []
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where
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iter : Int -> Int -> List (Maybe elem) -> io (List (Maybe elem))
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iter pos end acc
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= if pos >= end
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then pure (reverse acc)
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else do el <- readArray arr pos
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assert_total (iter (pos + 1) end (el :: acc))
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export
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fromList : List (Maybe elem) -> IO (IOArray elem)
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fromList ns
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= do arr <- newArray (cast (length ns))
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addToArray 0 ns arr
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pure arr
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where
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addToArray : Int -> List (Maybe elem) -> IOArray elem -> IO ()
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addToArray loc [] arr = pure ()
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addToArray loc (Nothing :: ns) arr
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= assert_total (addToArray (loc + 1) ns arr)
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addToArray loc (Just el :: ns) arr
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= do primIO $ prim__arraySet (content arr) loc (Just el)
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assert_total (addToArray (loc + 1) ns arr)
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