Sync with Cabal HEAD

1 files changed, 41 insertions, 0 deletions

diff --git a/src/CabalHelper/Compiletime/Compat/Parsec.hs b/src/CabalHelper/Compiletime/Compat/Parsec.hs
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+++ b/src/CabalHelper/Compiletime/Compat/Parsec.hs
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+-- cabal-helper: Simple interface to Cabal's configuration state
+-- Copyright (C) 2018  Daniel Gröber <cabal-helper@dxld.at>
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation, either version 3 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+-- You should have received a copy of the GNU General Public License
+-- along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+{-# LANGUAGE CPP #-}
+module CabalHelper.Compiletime.Compat.Parsec
+    ( absorbParsecFailure
+    , eitherParsec
+    ) where
+
+#if MIN_VERSION_Cabal(2,5,0)
+import Distribution.Parsec.Class
+#else
+import qualified Distribution.Compat.ReadP as Dist
+import Distribution.Text
+#endif
+
+absorbParsecFailure :: String -> Either String a -> a
+absorbParsecFailure _ (Right x) = x
+absorbParsecFailure ctx (Left err) =
+    error $ "Error parsing in '"++ctx++"': " ++ err
+
+#if !MIN_VERSION_Cabal(2,5,0)
+eitherParsec :: Text t => String -> Either String t
+eitherParsec i =
+  case filter ((=="") . snd) $ Dist.readP_to_S parse i of
+    (a,""):[] -> Right a
+    _ -> Left $ show i
+#endif