Markdown reader: don't lose parentheses in URLs.

Added tests.  This fixes a regression from 1.10.x.  Closes #786.

src/Text/Pandoc/Readers/Markdown.hs

@@ -287,8 +287,7 @@ referenceKey = try $ do
 referenceTitle :: MarkdownParser String
 referenceTitle = try $ do
   skipSpaces >> optional newline >> skipSpaces
-  let parenTit = charsInBalanced '(' ')' litChar
-  quotedTitle '"' <|> quotedTitle '\'' <|> parenTit
+  quotedTitle '"' <|> quotedTitle '\'' <|> charsInBalanced '(' ')' litChar
 
 -- A link title in quotes
 quotedTitle :: Char -> MarkdownParser String
@@ -1494,13 +1493,18 @@ reference :: MarkdownParser (F Inlines, String)
 reference = do notFollowedBy' (string "[^")   -- footnote reference
                withRaw $ trimInlinesF <$> inlinesInBalancedBrackets
 
+parenthesizedChars :: MarkdownParser [Char]
+parenthesizedChars = do
+  result <- charsInBalanced '(' ')' litChar
+  return $ '(' : result ++ ")"
+
 -- source for a link, with optional title
 source :: MarkdownParser (String, String)
 source = do
   char '('
   skipSpaces
   let urlChunk = try $ notFollowedBy (oneOf "\"')") >>
-                          (charsInBalanced '(' ')' litChar <|> count 1 litChar)
+                          (parenthesizedChars <|> count 1 litChar)
   let sourceURL = (unwords . words . concat) <$> many urlChunk
   let betweenAngles = try $
          char '<' >> manyTill litChar (char '>')

tests/markdown-reader-more.native

@@ -130,4 +130,8 @@
 ,Para [Link [Str "link"] ("/\252rl","\246\246!")]
 ,Para [Link [Str "http://g\246\246gle.com"] ("http://g\246\246gle.com","")]
 ,Para [Link [Str "me@ex\228mple.com"] ("mailto:me@ex\228mple.com","")]
-,Para [Link [Str "foobar"] ("/\252rl","\246\246!")]]
+,Para [Link [Str "foobar"] ("/\252rl","\246\246!")]
+,Header 2 ("parentheses-in-urls",[],[]) [Str "Parentheses",Space,Str "in",Space,Str "URLs"]
+,Para [Link [Str "link"] ("/hi(there)","")]
+,Para [Link [Str "link"] ("/hithere)","")]
+,Para [Link [Str "linky"] ("hi_(there_(nested))","")]]

tests/markdown-reader-more.txt

@@ -221,3 +221,13 @@ Empty cells
 [foobar]
 
 [foobar]: /ürl "öö!"
+
+## Parentheses in URLs
+
+[link](/hi(there))
+
+[link](/hithere\))
+
+[linky]
+
+[linky]: hi_(there_(nested))