3 files changed, 16 insertions, 12 deletions
diff --git a/src/Text/Pandoc/Filter.hs b/src/Text/Pandoc/Filter.hs
index 8fe93089a..1c25a5a6e 100644
--- a/src/Text/Pandoc/Filter.hs
+++ b/src/Text/Pandoc/Filter.hs
@@ -42,20 +42,29 @@ import Text.Pandoc.Definition (Pandoc)
 import Text.Pandoc.Options (ReaderOptions)
 import qualified Text.Pandoc.Filter.JSON as JSONFilter
 import qualified Text.Pandoc.Filter.Lua as LuaFilter
+import qualified Text.Pandoc.Filter.Path as Path
 
+-- | Type of filter and path to filter file.
 data Filter = LuaFilter FilePath
             | JSONFilter FilePath
             deriving (Show)
 
+-- | Modify the given document using a filter.
 applyFilters :: ReaderOptions
              -> [Filter]
              -> [String]
              -> Pandoc
              -> PandocIO Pandoc
-applyFilters ropts filters args d =
-  foldrM ($) d $ map applyFilter filters
+applyFilters ropts filters args d = do
+  expandedFilters <- mapM expandFilterPath filters
+  foldrM ($) d $ map applyFilter expandedFilters
  where
   applyFilter (JSONFilter f) = JSONFilter.apply ropts args f
   applyFilter (LuaFilter f)  = LuaFilter.apply ropts args f
 
+-- | Expand paths of filters, searching the data directory.
+expandFilterPath :: Filter -> PandocIO Filter
+expandFilterPath (LuaFilter fp) = LuaFilter <$> Path.expandFilterPath fp
+expandFilterPath (JSONFilter fp) = JSONFilter <$> Path.expandFilterPath fp
+
 $(deriveJSON defaultOptions ''Filter)
diff --git a/src/Text/Pandoc/Filter/JSON.hs b/src/Text/Pandoc/Filter/JSON.hs
index 97b291603..2846e42e2 100644
--- a/src/Text/Pandoc/Filter/JSON.hs
+++ b/src/Text/Pandoc/Filter/JSON.hs
@@ -44,7 +44,6 @@ 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)
@@ -56,9 +55,7 @@ apply :: ReaderOptions
       -> FilePath
       -> Pandoc
       -> PandocIO Pandoc
-apply ropts args f d = do
-  f' <- expandFilterPath f
-  liftIO $ externalFilter ropts f' args d
+apply ropts args f = liftIO . externalFilter ropts f args
 
 externalFilter :: MonadIO m
                => ReaderOptions -> FilePath -> [String] -> Pandoc -> m Pandoc
diff --git a/src/Text/Pandoc/Filter/Lua.hs b/src/Text/Pandoc/Filter/Lua.hs
index a6dc7b6cc..e5c34c71c 100644
--- a/src/Text/Pandoc/Filter/Lua.hs
+++ b/src/Text/Pandoc/Filter/Lua.hs
@@ -36,7 +36,6 @@ import Control.Monad ((>=>))
 import Text.Pandoc.Class (PandocIO)
 import Text.Pandoc.Definition (Pandoc)
 import Text.Pandoc.Error (PandocError (PandocFilterError))
-import Text.Pandoc.Filter.Path (expandFilterPath)
 import Text.Pandoc.Lua (Global (..), LuaException (..),
                         runLua, runFilterFile, setGlobals)
 import Text.Pandoc.Options (ReaderOptions)
@@ -49,17 +48,16 @@ apply :: ReaderOptions
       -> FilePath
       -> Pandoc
       -> PandocIO Pandoc
-apply ropts args f doc = do
-  filterPath <- expandFilterPath f
+apply ropts args fp doc = do
   let format = case args of
                  (x:_) -> x
                  _     -> error "Format not supplied for Lua filter"
-  runLua >=> forceResult filterPath $ do
+  runLua >=> forceResult fp $ do
     setGlobals [ FORMAT format
                , PANDOC_READER_OPTIONS ropts
-               , PANDOC_SCRIPT_FILE filterPath
+               , PANDOC_SCRIPT_FILE fp
                ]
-    runFilterFile filterPath doc
+    runFilterFile fp doc
 
 forceResult :: FilePath -> Either LuaException Pandoc -> PandocIO Pandoc
 forceResult fp eitherResult = case eitherResult of