A suggestion to turn defaultUserDataDir :: IO FilePath into defaultUserDataDirs :: IO [FilePath]

src/Text/Pandoc/Shared.hs

@@ -92,7 +92,7 @@ module Text.Pandoc.Shared (
                      safeRead,
                      safeStrRead,
                      -- * User data directory
-                     defaultUserDataDir,
+                     defaultUserDataDirs,
                      -- * Version
                      pandocVersion
                     ) where
@@ -1017,13 +1017,15 @@ safeStrRead s = case reads s of
 -- is present, we return the XDG data directory.  If the XDG data directory
 -- is not defined (e.g. because we are in an environment where $HOME is
 -- not defined), we return the empty string.
-defaultUserDataDir :: IO FilePath
+defaultUserDataDirs :: IO [FilePath]
-defaultUserDataDir = do
+defaultUserDataDirs = do
   xdgDir <- E.catch (getXdgDirectory XdgData "pandoc")
                (\(_ :: E.SomeException) -> return mempty)
   legacyDir <- getAppUserDataDirectory "pandoc"
   xdgExists <- doesDirectoryExist xdgDir
   legacyDirExists <- doesDirectoryExist legacyDir
-  if not xdgExists && legacyDirExists
+  let mainDir = if not xdgExists && legacyDirExists then legacyDir else xdgDir
-     then return legacyDir
+  xdgDirs <- E.catch (getXdgDirectoryList XdgDataDirs)
-     else return xdgDir
+               (\(_ :: E.SomeException) -> return mempty)
+  return (mainDir:xdgDirs)
+