Markdown reader: Better handle quote characters in inline links.

This was previously failing to be recognized as a link:

    [Test](http://en.wikipedia.org/wiki/Ward's_method)

Closes #1534.

src/Text/Pandoc/Readers/Markdown.hs

@@ -1635,8 +1635,10 @@ source :: MarkdownParser (String, String)
 source = do
   char '('
   skipSpaces
-  let urlChunk = try $ notFollowedBy (oneOf "\"')") >>
-                          (parenthesizedChars <|> count 1 litChar)
+  let urlChunk =
+            try parenthesizedChars
+        <|> (notFollowedBy (oneOf " )") >> (count 1 litChar))
+        <|> try (many1 spaceChar <* notFollowedBy (oneOf "\"')"))
   let sourceURL = (unwords . words . concat) <$> many urlChunk
   let betweenAngles = try $
          char '<' >> manyTill litChar (char '>')

tests/markdown-reader-more.native

@@ -5,9 +5,10 @@
 ,Plain [RawInline (Format "tex") "\\placeformula "]
 ,RawBlock (Format "context") "\\startformula\n   L_{1} = L_{2}\n   \\stopformula"
 ,RawBlock (Format "context") "\\start[a2]\n\\start[a2]\n\\stop[a2]\n\\stop[a2]"
-,Header 2 ("urls-with-spaces",[],[]) [Str "URLs",Space,Str "with",Space,Str "spaces"]
+,Header 2 ("urls-with-spaces-and-punctuation",[],[]) [Str "URLs",Space,Str "with",Space,Str "spaces",Space,Str "and",Space,Str "punctuation"]
 ,Para [Link [Str "foo"] ("/bar%20and%20baz",""),Space,Link [Str "foo"] ("/bar%20and%20baz",""),Space,Link [Str "foo"] ("/bar%20and%20baz",""),Space,Link [Str "foo"] ("bar%20baz","title")]
 ,Para [Link [Str "baz"] ("/foo%20foo",""),Space,Link [Str "bam"] ("/foo%20fee",""),Space,Link [Str "bork"] ("/foo/zee%20zob","title")]
+,Para [Link [Str "Ward\8217s",Space,Str "method."] ("http://en.wikipedia.org/wiki/Ward's_method","")]
 ,Header 2 ("horizontal-rules-with-spaces-at-end",[],[]) [Str "Horizontal",Space,Str "rules",Space,Str "with",Space,Str "spaces",Space,Str "at",Space,Str "end"]
 ,HorizontalRule
 ,HorizontalRule

tests/markdown-reader-more.txt

@@ -28,7 +28,7 @@
 \stop[a2]
 \stop[a2]
 
-## URLs with spaces
+## URLs with spaces and punctuation
 
 [foo](/bar and baz)
 [foo](/bar
@@ -42,6 +42,8 @@
 [bam]:  /foo fee   
 [bork]:  /foo/zee zob   (title)
 
+[Ward's method.](http://en.wikipedia.org/wiki/Ward's_method)
+
 ## Horizontal rules with spaces at end
 
 * * * * *