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Diffstat (limited to 'src/Text/Pandoc/Filter/JSON.hs')
| -rw-r--r-- | src/Text/Pandoc/Filter/JSON.hs | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/src/Text/Pandoc/Filter/JSON.hs b/src/Text/Pandoc/Filter/JSON.hs new file mode 100644 index 000000000..5772c2c41 --- /dev/null +++ b/src/Text/Pandoc/Filter/JSON.hs @@ -0,0 +1,97 @@ +{- +Copyright (C) 2006-2018 John MacFarlane <jgm@berkeley.edu> + +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 2 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, write to the Free Software +Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA +-} + +{- | + Module : Text.Pandoc.Filter + Copyright : Copyright (C) 2006-2018 John MacFarlane + License : GNU GPL, version 2 or above + + Maintainer : John MacFarlane <jgm@berkeley@edu> + Stability : alpha + Portability : portable + +Programmatically modifications of pandoc documents via JSON filters. +-} +module Text.Pandoc.Filter.JSON (apply) where + +import Control.Monad (unless, when) +import Control.Monad.Trans (MonadIO (liftIO)) +import Data.Aeson (eitherDecode', encode) +import Data.Char (toLower) +import Data.Maybe (isNothing) +import System.Directory (executable, doesFileExist, findExecutable, + getPermissions) +import System.Environment (getEnvironment) +import System.Exit (ExitCode (..)) +import System.FilePath ((</>), takeExtension) +import Text.Pandoc.Class (PandocIO) +import Text.Pandoc.Error (PandocError (PandocFilterError)) +import Text.Pandoc.Definition (Pandoc) +import Text.Pandoc.Filter.Path (expandFilterPath) +import Text.Pandoc.Options (ReaderOptions) +import Text.Pandoc.Process (pipeProcess) +import Text.Pandoc.Shared (pandocVersion) +import qualified Control.Exception as E +import qualified Text.Pandoc.UTF8 as UTF8 + +apply :: ReaderOptions + -> [String] + -> FilePath + -> Pandoc + -> PandocIO Pandoc +apply ropts args f d = do + f' <- expandFilterPath f + liftIO $ externalFilter ropts f' args d + +externalFilter :: MonadIO m + => ReaderOptions -> FilePath -> [String] -> Pandoc -> m Pandoc +externalFilter ropts f args' d = liftIO $ do + exists <- doesFileExist f + isExecutable <- if exists + then executable <$> getPermissions f + else return True + let (f', args'') = if exists + then case map toLower (takeExtension f) of + _ | isExecutable -> ("." </> f, args') + ".py" -> ("python", f:args') + ".hs" -> ("runhaskell", f:args') + ".pl" -> ("perl", f:args') + ".rb" -> ("ruby", f:args') + ".php" -> ("php", f:args') + ".js" -> ("node", f:args') + ".r" -> ("Rscript", f:args') + _ -> (f, args') + else (f, args') + unless (exists && isExecutable) $ do + mbExe <- findExecutable f' + when (isNothing mbExe) $ + E.throwIO $ PandocFilterError f ("Could not find executable " ++ f') + env <- getEnvironment + let env' = Just + ( ("PANDOC_VERSION", pandocVersion) + : ("PANDOC_READER_OPTIONS", UTF8.toStringLazy (encode ropts)) + : env ) + (exitcode, outbs) <- E.handle filterException $ + pipeProcess env' f' args'' $ encode d + case exitcode of + ExitSuccess -> either (E.throwIO . PandocFilterError f) + return $ eitherDecode' outbs + ExitFailure ec -> E.throwIO $ PandocFilterError f + ("Filter returned error status " ++ show ec) + where filterException :: E.SomeException -> IO a + filterException e = E.throwIO $ PandocFilterError f (show e) |