base-prelude 0.1.9 → 0.1.10

raw patch · 2 files changed

+31/−2 lines, 2 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• base-prelude.cabal +1/−1
• library/BasePrelude.hs +30/−1

@@ -1,7 +1,7 @@ name:   base-prelude version:-  0.1.9+  0.1.10 synopsis:   The most complete prelude formed from only the "base" package description:

@@ -15,6 +15,9 @@   traceShowM,   -- ** Data.Ord   Down(..),+  -- ** Text.Read+  readEither,+  readMaybe, ) where @@ -66,9 +69,12 @@ import System.Mem as Exports import System.Mem.StableName as Exports import System.Timeout as Exports-import Text.Read as Exports (readMaybe, readEither)+import Text.Read as Exports (Read(..)) import Unsafe.Coerce as Exports +import qualified Text.ParserCombinators.ReadPrec as ReadPrec+import qualified Text.ParserCombinators.ReadP as ReadP+ -- Reimplementations ------------------------- @@ -120,3 +126,26 @@  instance Ord a => Ord (Down a) where   compare (Down x) (Down y) = y `compare` x+++-- | Parse a string using the 'Read' instance.+-- Succeeds if there is exactly one valid result.+-- A 'Left' value indicates a parse error.+readEither :: Read a => String -> Either String a+readEither s =+  case [ x | (x,"") <- ReadPrec.readPrec_to_S read' ReadPrec.minPrec s ] of+    [x] -> Right x+    []  -> Left "Prelude.read: no parse"+    _   -> Left "Prelude.read: ambiguous parse"+  where+    read' =+      do x <- readPrec+         ReadPrec.lift ReadP.skipSpaces+         return x++-- | Parse a string using the 'Read' instance.+-- Succeeds if there is exactly one valid result.+readMaybe :: Read a => String -> Maybe a+readMaybe s = case readEither s of+                Left _  -> Nothing+                Right a -> Just a