Fix definition lists with internal links in terms (closes #1032).

This fix puts braces around a term that contains an internal
link, to avoid problems with square brackets.

src/Text/Pandoc/Writers/LaTeX.hs

@@ -513,8 +513,15 @@ listItemToLaTeX lst = blockListToLaTeX lst >>= return .  (text "\\item" $$) .
 defListItemToLaTeX :: ([Inline], [[Block]]) -> State WriterState Doc
 defListItemToLaTeX (term, defs) = do
     term' <- inlineListToLaTeX term
+    -- put braces around term if it contains an internal link,
+    -- since otherwise we get bad bracket interactions: \item[\hyperref[..]
+    let isInternalLink (Link _ ('#':_,_)) = True
+        isInternalLink _                  = False
+    let term'' = if any isInternalLink term
+                    then braces term'
+                    else term'
     def'  <- liftM vsep $ mapM blockListToLaTeX defs
-    return $ "\\item" <> brackets term' $$ def'
+    return $ "\\item" <> brackets term'' $$ def'
 
 -- | Craft the section header, inserting the secton reference, if supplied.
 sectionHeader :: Bool    -- True for unnumbered

tests/Tests/Writers/LaTeX.hs

@@ -39,6 +39,11 @@ tests = [ testGroup "code blocks"
           , test latexListing "no identifier" $ codeBlock "hi" =?>
             ("\\begin{lstlisting}\nhi\n\\end{lstlisting}" :: String)
           ]
+        , testGroup "definition lists"
+          [ "with internal link" =: definitionList [(link "#go" "" (str "testing"),
+             [plain (text "hi there")])] =?>
+            "\\begin{description}\n\\itemsep1pt\\parskip0pt\\parsep0pt\n\\item[{\\hyperref[go]{testing}}]\nhi there\n\\end{description}"
+          ]
         , testGroup "math"
           [ "escape |" =: para (math "\\sigma|_{\\{x\\}}") =?>
             "$\\sigma|_{\\{x\\}}$"