Org reader: absolute, relative paths in links

The org reader was to restrictive when parsing links, some relative
links and links to files given as absolute paths were not recognized
correctly.  The org reader's link parsing function was amended to handle
such cases properly.

This fixes #1741

1 files changed, 19 insertions, 14 deletions

diff --git a/src/Text/Pandoc/Readers/Org.hs b/src/Text/Pandoc/Readers/Org.hs
index 1ddfeab87..2f149765e 100644
--- a/src/Text/Pandoc/Readers/Org.hs
+++ b/src/Text/Pandoc/Readers/Org.hs
@@ -1139,27 +1139,32 @@ applyCustomLinkFormat link = do
     formatter <- M.lookup linkType <$> asksF orgStateLinkFormatters
     return $ maybe link ($ drop 1 rest) formatter
 
-
 linkToInlinesF :: String -> Inlines -> F Inlines
-linkToInlinesF s@('#':_) = pure . B.link s ""
-linkToInlinesF s
-    | isImageFilename s = const . pure $ B.image s "" ""
-    | isUri s           = pure . B.link s ""
-    | isRelativeUrl s   = pure . B.link s ""
-linkToInlinesF s = \title -> do
-  anchorB <- (s `elem`) <$> asksF orgStateAnchorIds
-  if anchorB
-    then pure $ B.link ('#':s) "" title
-    else pure $ B.emph title
-
-isRelativeUrl :: String -> Bool
-isRelativeUrl s = (':' `notElem` s) && ("./" `isPrefixOf` s)
+linkToInlinesF s =
+  case s of
+    ('#':_) -> pure . B.link s ""
+    _ | isImageFilename s     -> const . pure $ B.image s "" ""
+    _ | isUri s               -> pure . B.link s ""
+    _ | isRelativeFilePath s  -> pure . B.link s ""
+    _ | isAbsoluteFilePath s  -> pure . B.link ("file://" ++ s) ""
+    _ -> \title -> do
+           anchorB <- (s `elem`) <$> asksF orgStateAnchorIds
+           if anchorB
+             then pure $ B.link ('#':s) "" title
+             else pure $ B.emph title
+
+isRelativeFilePath :: String -> Bool
+isRelativeFilePath s = (("./" `isPrefixOf` s) || ("../" `isPrefixOf` s)) &&
+                       (':' `notElem` s)
 
 isUri :: String -> Bool
 isUri s = let (scheme, path) = break (== ':') s
           in all (\c -> isAlphaNum c || c `elem` ".-") scheme
              && not (null path)
 
+isAbsoluteFilePath :: String -> Bool
+isAbsoluteFilePath = ('/' ==) . head
+
 isImageFilename :: String -> Bool
 isImageFilename filename =
   any (\x -> ('.':x)  `isSuffixOf` filename) imageExtensions &&