@@ -184,7 +184,16 @@ blockToMarkdown _ (RawHtml str) = return $ text str
184184blockToMarkdown _ HorizontalRule = return $ text "\n* * * * *\n"
185185blockToMarkdown opts (Header level inlines) = do
186186 contents <- inlineListToMarkdown opts inlines
187− return $ text ((replicate level '#') ++ " ") <> contents <> text "\n"
187+ -- use setext style headers if in literate haskell mode.
188+ -- ghc interprets '#' characters in column 1 as line number specifiers.
189+ if writerLiterateHaskell opts
190+ then let len = length $ render contents
191+ in return $ contents <> text "\n" <>
192+ case level of
193+ 1 -> text $ replicate len '=' ++ "\n"
194+ 2 -> text $ replicate len '-' ++ "\n"
195+ _ -> empty
196+ else return $ text ((replicate level '#') ++ " ") <> contents <> text "\n"
188197blockToMarkdown opts (CodeBlock (_,classes,_) str) | "haskell" `elem` classes &&
189198 writerLiterateHaskell opts =
190199 return $ (vcat $ map (text "> " <>) $ map text (lines str)) <> text "\n"