diff options
Diffstat (limited to 'src/Text/Pandoc/Class.hs')
| -rw-r--r-- | src/Text/Pandoc/Class.hs | 49 |
1 files changed, 39 insertions, 10 deletions
diff --git a/src/Text/Pandoc/Class.hs b/src/Text/Pandoc/Class.hs index f83683d4c..46e300953 100644 --- a/src/Text/Pandoc/Class.hs +++ b/src/Text/Pandoc/Class.hs @@ -5,7 +5,8 @@ {-# LANGUAGE FlexibleContexts #-} {- -Copyright (C) 2016 Jesse Rosenthal <jrosenthal@jhu.edu> +Copyright (C) 2016-17 Jesse Rosenthal <jrosenthal@jhu.edu> +and John MacFarlane. 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 @@ -24,7 +25,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA {- | Module : Text.Pandoc.Class - Copyright : Copyright (C) 2016 Jesse Rosenthal + Copyright : Copyright (C) 2016-17 Jesse Rosenthal, John MacFarlane License : GNU GPL, version 2 or above Maintainer : Jesse Rosenthal <jrosenthal@jhu.edu> @@ -122,36 +123,64 @@ import qualified Data.Map as M import Text.Pandoc.Error import qualified Debug.Trace +-- | The PandocMonad typeclass contains all the potentially +-- IO-related functions used in pandoc's readers and writers. +-- Instances of this typeclass may implement these functions +-- in IO (as in 'PandocIO') or using an internal state that +-- represents a file system, time, and so on (as in 'PandocPure'). class (Functor m, Applicative m, Monad m, MonadError PandocError m) => PandocMonad m where + -- | Lookup an environment variable. lookupEnv :: String -> m (Maybe String) + -- | Get the current (UTC) time. getCurrentTime :: m UTCTime + -- | Get the locale's time zone. getCurrentTimeZone :: m TimeZone + -- | Return a new generator for random numbers. newStdGen :: m StdGen + -- | Return a new unique integer. newUniqueHash :: m Int + -- | Retrieve contents and mime type from a URL, raising + -- an error on failure. openURL :: String -> m (B.ByteString, Maybe MimeType) + -- | Read the lazy ByteString contents from a file path, + -- raising an error on failure. readFileLazy :: FilePath -> m BL.ByteString + -- | Read the strict ByteString contents from a file path, + -- raising an error on failure. readFileStrict :: FilePath -> m B.ByteString + -- | Read file from specified user data directory or, + -- if not found there, from Cabal data directory. readDataFile :: Maybe FilePath -> FilePath -> m B.ByteString + -- | Return a list of paths that match a glob, relative to + -- the working directory. See 'System.FilePath.Glob' for + -- the glob syntax. glob :: String -> m [FilePath] + -- | Return the modification time of a file. getModificationTime :: FilePath -> m UTCTime + -- | Get the value of the 'CommonState' used by all instances + -- of 'PandocMonad'. getCommonState :: m CommonState + -- | Set the value of the 'CommonState' used by all instances + -- of 'PandocMonad'. + -- | Get the value of a specific field of 'CommonState'. putCommonState :: CommonState -> m () - + -- | Get the value of a specific field of 'CommonState'. getsCommonState :: (CommonState -> a) -> m a getsCommonState f = f <$> getCommonState - + -- | Modify the 'CommonState'. modifyCommonState :: (CommonState -> CommonState) -> m () modifyCommonState f = getCommonState >>= putCommonState . f - + -- Output a log message. + logOutput :: LogMessage -> m () + -- Output a debug message to sterr, using 'Debug.Trace.trace'. + -- Note: this writes to stderr even in pure instances. trace :: String -> m () trace msg = do tracing <- getsCommonState stTrace when tracing $ Debug.Trace.trace ("[trace] " ++ msg) (return ()) - logOutput :: LogMessage -> m () - --- Functions defined for all PandocMonad instances +-- * Functions defined for all PandocMonad instances setVerbosity :: PandocMonad m => Verbosity -> m () setVerbosity verbosity = @@ -194,10 +223,10 @@ setResourcePath ps = modifyCommonState $ \st -> st{stResourcePath = ps} getResourcePath :: PandocMonad m => m [FilePath] getResourcePath = getsCommonState stResourcePath -getPOSIXTime :: (PandocMonad m) => m POSIXTime +getPOSIXTime :: PandocMonad m => m POSIXTime getPOSIXTime = utcTimeToPOSIXSeconds <$> getCurrentTime -getZonedTime :: (PandocMonad m) => m ZonedTime +getZonedTime :: PandocMonad m => m ZonedTime getZonedTime = do t <- getCurrentTime tz <- getCurrentTimeZone |