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Diffstat (limited to 'Haskell-book/09/src/EnumFromTo.purs')
| -rw-r--r-- | Haskell-book/09/src/EnumFromTo.purs | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/Haskell-book/09/src/EnumFromTo.purs b/Haskell-book/09/src/EnumFromTo.purs new file mode 100644 index 0000000..f389c31 --- /dev/null +++ b/Haskell-book/09/src/EnumFromTo.purs @@ -0,0 +1,15 @@ +module EnumFromTo where + +import Data.Array ((:), reverse) +import Data.Enum (class Enum, succ) +import Data.Maybe (Maybe(..)) +import Prelude + +enumFromTo :: forall a. Enum a => a -> a -> Array a +enumFromTo start end = reverse $ enumFromTo' [] (Just start) + where enumFromTo' :: Array a -> Maybe a -> Array a + enumFromTo' acc (Just start') + | start' > end = acc + | start' == end = start' : acc + | otherwise = enumFromTo' (start' : acc) (succ start') + enumFromTo' acc Nothing = acc |
