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| author | sheaf <sam.derbyshire@gmail.com> | 2022-11-24 23:15:48 +0000 |
|---|---|---|
| committer | Marge Bot <ben+marge-bot@smart-cactus.org> | 2022-11-25 04:38:28 -0500 |
| commit | 1f1b99b86ab2b005604aea08b0614279a8ad1244 (patch) | |
| tree | 102e0c622093933371d3e1b6c90a8277b0de2d18 | |
| parent | 5943e739f8060bcc9867ef048a462f2c465fde00 (diff) | |
| download | haskell-1f1b99b86ab2b005604aea08b0614279a8ad1244.tar.gz | |
Review suggestions for assorted fixes to avoid Data.List.{head,tail}
| -rw-r--r-- | libraries/ghc-boot/GHC/BaseDir.hs | 5 | ||||
| -rw-r--r-- | libraries/ghc-boot/GHC/Data/ShortText.hs | 9 |
2 files changed, 8 insertions, 6 deletions
diff --git a/libraries/ghc-boot/GHC/BaseDir.hs b/libraries/ghc-boot/GHC/BaseDir.hs index 66ed339e32..0001837f75 100644 --- a/libraries/ghc-boot/GHC/BaseDir.hs +++ b/libraries/ghc-boot/GHC/BaseDir.hs @@ -16,7 +16,8 @@ module GHC.BaseDir where import Prelude -- See Note [Why do we import Prelude here?] -import Data.List (stripPrefix, uncons) +import Data.List (stripPrefix) +import Data.Maybe (listToMaybe) import System.FilePath -- Windows @@ -37,7 +38,7 @@ expandTopDir = expandPathVar "topdir" expandPathVar :: String -> FilePath -> String -> String expandPathVar var value str | Just str' <- stripPrefix ('$':var) str - , maybe True (isPathSeparator . fst) (uncons str') + , maybe True isPathSeparator (listToMaybe str') = value ++ expandPathVar var value str' expandPathVar var value (x:xs) = x : expandPathVar var value xs expandPathVar _ _ [] = [] diff --git a/libraries/ghc-boot/GHC/Data/ShortText.hs b/libraries/ghc-boot/GHC/Data/ShortText.hs index 477d2b9a6d..9ea261435f 100644 --- a/libraries/ghc-boot/GHC/Data/ShortText.hs +++ b/libraries/ghc-boot/GHC/Data/ShortText.hs @@ -47,7 +47,6 @@ import Control.DeepSeq as DeepSeq import Data.Binary import qualified Data.ByteString.Char8 as B8 import qualified Data.ByteString.Short.Internal as SBS -import Data.List (uncons) import GHC.Exts import GHC.IO import GHC.Utils.Encoding @@ -101,9 +100,11 @@ splitFilePath st = DeepSeq.force $ map (ShortText . SBS.toShort) $ B8.splitWith -- question, this may or may not be the actual first character in the string due to Unicode -- non-printable characters. head :: ShortText -> Char -head st = case uncons (unpack st) of - Nothing -> error "head: Empty ShortText" - Just (hd, _) -> hd +head st + | hd:_ <- unpack st + = hd + | otherwise + = error "head: Empty ShortText" -- | /O(n)/ The 'stripPrefix' function takes two 'ShortText's and returns 'Just' the remainder of -- the second iff the first is its prefix, and otherwise Nothing. |