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-rw-r--r--src/Text/Pandoc/Class.hs88
1 files changed, 21 insertions, 67 deletions
diff --git a/src/Text/Pandoc/Class.hs b/src/Text/Pandoc/Class.hs
index 25d6d2927..aebe617b1 100644
--- a/src/Text/Pandoc/Class.hs
+++ b/src/Text/Pandoc/Class.hs
@@ -4,6 +4,7 @@
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE UndecidableInstances #-}
{-
Copyright (C) 2016-17 Jesse Rosenthal <jrosenthal@jhu.edu>
@@ -123,11 +124,9 @@ import System.FilePath ((</>), (<.>), takeDirectory,
import qualified System.FilePath.Glob as IO (glob)
import qualified System.Directory as IO (getModificationTime)
import Control.Monad as M (fail)
-import Control.Monad.Reader (ReaderT)
import Control.Monad.State.Strict
import Control.Monad.Except
-import Control.Monad.Writer (WriterT)
-import Control.Monad.RWS (RWST)
+import Control.Monad.Trans (MonadTrans)
import Data.Word (Word8)
import Data.Default
import System.IO.Error
@@ -841,53 +840,13 @@ instance PandocMonad PandocPure where
logOutput _msg = return ()
-instance PandocMonad m => PandocMonad (ParsecT s st m) where
- lookupEnv = lift . lookupEnv
- getCurrentTime = lift getCurrentTime
- getCurrentTimeZone = lift getCurrentTimeZone
- newStdGen = lift newStdGen
- newUniqueHash = lift newUniqueHash
- openURL = lift . openURL
- readFileLazy = lift . readFileLazy
- readFileStrict = lift . readFileStrict
- glob = lift . glob
- fileExists = lift . fileExists
- getDataFileName = lift . getDataFileName
- getModificationTime = lift . getModificationTime
- getCommonState = lift getCommonState
- putCommonState = lift . putCommonState
- trace msg = do
- tracing <- getsCommonState stTrace
- when tracing $ do
- pos <- getPosition
- Debug.Trace.trace
- ("[trace] Parsed " ++ msg ++ " at line " ++
- show (sourceLine pos) ++
- if sourceName pos == "chunk"
- then " of chunk"
- else "")
- (return ())
- logOutput = lift . logOutput
-
-
-instance PandocMonad m => PandocMonad (ReaderT r m) where
- lookupEnv = lift . lookupEnv
- getCurrentTime = lift getCurrentTime
- getCurrentTimeZone = lift getCurrentTimeZone
- newStdGen = lift newStdGen
- newUniqueHash = lift newUniqueHash
- openURL = lift . openURL
- readFileLazy = lift . readFileLazy
- readFileStrict = lift . readFileStrict
- glob = lift . glob
- fileExists = lift . fileExists
- getDataFileName = lift . getDataFileName
- getModificationTime = lift . getModificationTime
- getCommonState = lift getCommonState
- putCommonState = lift . putCommonState
- logOutput = lift . logOutput
-
-instance (PandocMonad m, Monoid w) => PandocMonad (WriterT w m) where
+-- This requires UndecidableInstances. We could avoid that
+-- by repeating the definitions below for every monad transformer
+-- we use: ReaderT, WriterT, StateT, RWST. But this seems to
+-- be harmless.
+instance (MonadTrans t, PandocMonad m, Functor (t m),
+ MonadError PandocError (t m), Monad (t m),
+ Applicative (t m)) => PandocMonad (t m) where
lookupEnv = lift . lookupEnv
getCurrentTime = lift getCurrentTime
getCurrentTimeZone = lift getCurrentTimeZone
@@ -904,7 +863,7 @@ instance (PandocMonad m, Monoid w) => PandocMonad (WriterT w m) where
putCommonState = lift . putCommonState
logOutput = lift . logOutput
-instance (PandocMonad m, Monoid w) => PandocMonad (RWST r w st m) where
+instance {-# OVERLAPS #-} PandocMonad m => PandocMonad (ParsecT s st m) where
lookupEnv = lift . lookupEnv
getCurrentTime = lift getCurrentTime
getCurrentTimeZone = lift getCurrentTimeZone
@@ -919,21 +878,16 @@ instance (PandocMonad m, Monoid w) => PandocMonad (RWST r w st m) where
getModificationTime = lift . getModificationTime
getCommonState = lift getCommonState
putCommonState = lift . putCommonState
+ trace msg = do
+ tracing <- getsCommonState stTrace
+ when tracing $ do
+ pos <- getPosition
+ Debug.Trace.trace
+ ("[trace] Parsed " ++ msg ++ " at line " ++
+ show (sourceLine pos) ++
+ if sourceName pos == "chunk"
+ then " of chunk"
+ else "")
+ (return ())
logOutput = lift . logOutput
-instance PandocMonad m => PandocMonad (StateT st m) where
- lookupEnv = lift . lookupEnv
- getCurrentTime = lift getCurrentTime
- getCurrentTimeZone = lift getCurrentTimeZone
- newStdGen = lift newStdGen
- newUniqueHash = lift newUniqueHash
- openURL = lift . openURL
- readFileLazy = lift . readFileLazy
- readFileStrict = lift . readFileStrict
- glob = lift . glob
- fileExists = lift . fileExists
- getDataFileName = lift . getDataFileName
- getModificationTime = lift . getModificationTime
- getCommonState = lift getCommonState
- putCommonState = lift . putCommonState
- logOutput = lift . logOutput