Added Attr field to Header.

Previously header ids were autogenerated by the writers.
Now they are generated (unless supplied explicitly) in the
markdown parser, if the `header_identifiers` extension is
selected.

In addition, the textile reader now supports id attributes on
headers.

17 files changed, 59 insertions, 51 deletions

diff --git a/src/Text/Pandoc/Writers/AsciiDoc.hs b/src/Text/Pandoc/Writers/AsciiDoc.hs
index b03bc77a8..30da6ac1a 100644
--- a/src/Text/Pandoc/Writers/AsciiDoc.hs
+++ b/src/Text/Pandoc/Writers/AsciiDoc.hs
@@ -126,10 +126,10 @@ blockToAsciiDoc opts (Para inlines) = do
 blockToAsciiDoc _ (RawBlock _ _) = return empty
 blockToAsciiDoc _ HorizontalRule =
   return $ blankline <> text "'''''" <> blankline
-blockToAsciiDoc opts (Header level inlines) = do
+blockToAsciiDoc opts (Header level (ident,_,_) inlines) = do
   contents <- inlineListToAsciiDoc opts inlines
   let len = offset contents
-  return $ contents <> cr <>
+  return $ ("[[" <> text ident <> "]]") $$ contents $$
          (case level of
                1  -> text $ replicate len '-'
                2  -> text $ replicate len '~'
diff --git a/src/Text/Pandoc/Writers/ConTeXt.hs b/src/Text/Pandoc/Writers/ConTeXt.hs
index 0663d537c..b9dcf0c71 100644
--- a/src/Text/Pandoc/Writers/ConTeXt.hs
+++ b/src/Text/Pandoc/Writers/ConTeXt.hs
@@ -190,7 +190,7 @@ blockToConTeXt (DefinitionList lst) =
   liftM vcat $ mapM defListItemToConTeXt lst
 blockToConTeXt HorizontalRule = return $ "\\thinrule" <> blankline
 -- If this is ever executed, provide a default for the reference identifier.
-blockToConTeXt (Header level lst) = sectionHeader "" level lst
+blockToConTeXt (Header level (ident,_,_) lst) = sectionHeader ident level lst
 blockToConTeXt (Table caption aligns widths heads rows) = do
     let colDescriptor colWidth alignment = (case alignment of
                                                AlignLeft    -> 'l'
diff --git a/src/Text/Pandoc/Writers/Docbook.hs b/src/Text/Pandoc/Writers/Docbook.hs
index fe768efc5..890feacbf 100644
--- a/src/Text/Pandoc/Writers/Docbook.hs
+++ b/src/Text/Pandoc/Writers/Docbook.hs
@@ -142,7 +142,7 @@ listItemToDocbook opts item =
 -- | Convert a Pandoc block element to Docbook.
 blockToDocbook :: WriterOptions -> Block -> Doc
 blockToDocbook _ Null = empty
-blockToDocbook _ (Header _ _) = empty -- should not occur after hierarchicalize
+blockToDocbook _ (Header _ _ _) = empty -- should not occur after hierarchicalize
 blockToDocbook opts (Plain lst) = inlinesToDocbook opts lst
 blockToDocbook opts (Para [Image txt (src,_)]) =
   let alt  = inlinesToDocbook opts txt
diff --git a/src/Text/Pandoc/Writers/Docx.hs b/src/Text/Pandoc/Writers/Docx.hs
index 069a5f6eb..839bb16d4 100644
--- a/src/Text/Pandoc/Writers/Docx.hs
+++ b/src/Text/Pandoc/Writers/Docx.hs
@@ -337,11 +337,13 @@ getUniqueId = liftIO $ (show . (+ 20) . hashUnique) `fmap` newUnique
 -- | Convert a Pandoc block element to OpenXML.
 blockToOpenXML :: WriterOptions -> Block -> WS [Element]
 blockToOpenXML _ Null = return []
-blockToOpenXML opts (Header lev lst) = do
+blockToOpenXML opts (Header lev (ident,_,_) lst) = do
   contents <- withParaProp (pStyle $ "Heading" ++ show lev) $
                blockToOpenXML opts (Para lst)
   usedIdents <- gets stSectionIds
-  let bookmarkName = uniqueIdent lst usedIdents
+  let bookmarkName = if null ident
+                        then uniqueIdent lst usedIdents
+                        else ident
   modify $ \s -> s{ stSectionIds = bookmarkName : stSectionIds s }
   id' <- getUniqueId
   let bookmarkStart = mknode "w:bookmarkStart" [("w:id", id')
diff --git a/src/Text/Pandoc/Writers/EPUB.hs b/src/Text/Pandoc/Writers/EPUB.hs
index b8a4bf1c6..493b762ac 100644
--- a/src/Text/Pandoc/Writers/EPUB.hs
+++ b/src/Text/Pandoc/Writers/EPUB.hs
@@ -119,18 +119,17 @@ writeEPUB opts doc@(Pandoc meta _) = do
 
   -- add level 1 header to beginning if none there
   let blocks' = case blocks of
-                      (Header 1 _ : _) -> blocks
-                      _                -> Header 1 (docTitle meta) : blocks
+                      (Header 1 _ _ : _) -> blocks
+                      _                  -> Header 1 ("",[],[]) (docTitle meta) : blocks
 
   let chapterHeaderLevel = writerEpubChapterLevel opts
-
   -- internal reference IDs change when we chunk the file,
   -- so that '#my-header-1' might turn into 'chap004.xhtml#my-header'.
   -- the next two lines fix that:
   let reftable = correlateRefs chapterHeaderLevel blocks'
   let blocks'' = replaceRefs reftable blocks'
 
-  let isChapterHeader (Header n _) = n <= chapterHeaderLevel
+  let isChapterHeader (Header n _ _) = n <= chapterHeaderLevel
       isChapterHeader _ = False
 
   let toChunks :: [Block] -> [[Block]]
@@ -145,8 +144,8 @@ writeEPUB opts doc@(Pandoc meta _) = do
         $ renderHtml
         $ writeHtml opts'
         $ case bs of
-              (Header _ xs : _) -> Pandoc (Meta xs [] []) bs
-              _                 -> Pandoc (Meta [] [] []) bs
+              (Header _ _ xs : _) -> Pandoc (Meta xs [] []) bs
+              _                   -> Pandoc (Meta [] [] []) bs
 
   let chapterEntries = zipWith chapToEntry [1..] chunks
 
@@ -444,7 +443,7 @@ correlateRefs chapterHeaderLevel bs =
               , chapterIdents = []
               , identTable = [] }
  where go :: Block -> State IdentState ()
-       go (Header n ils) = do
+       go (Header n _ ils) = do
           when (n <= chapterHeaderLevel) $
               modify $ \s -> s{ chapterNumber = chapterNumber s + 1
                               , chapterIdents = [] }
diff --git a/src/Text/Pandoc/Writers/FB2.hs b/src/Text/Pandoc/Writers/FB2.hs
index 301d80c54..eeb4616b4 100644
--- a/src/Text/Pandoc/Writers/FB2.hs
+++ b/src/Text/Pandoc/Writers/FB2.hs
@@ -158,7 +158,7 @@ renderSection level (ttl, body) = do
     return $ el "section" (title ++ content)
   where
     hasSubsections = any isHeader
-    isHeader (Header _ _) = True
+    isHeader (Header _ _ _) = True
     isHeader _ = False
 
 -- | Only <p> and <empty-line> are allowed within <title> in FB2.
@@ -186,13 +186,13 @@ splitSections level blocks = reverse $ revSplit (reverse blocks)
     let (lastsec, before) = break sameLevel rblocks
         (header, prevblocks) =
             case before of
-              ((Header n title):prevblocks') ->
+              ((Header n _ title):prevblocks') ->
                   if n == level
                      then (title, prevblocks')
                      else ([], before)
               _ -> ([], before)
     in (header, reverse lastsec) : revSplit prevblocks
-  sameLevel (Header n _) = n == level
+  sameLevel (Header n _ _) = n == level
   sameLevel _ = False
 
 -- | Make another FictionBook body with footnotes.
@@ -361,7 +361,7 @@ blockToXml (DefinitionList defs) =
       needsBreak (Para _) = False
       needsBreak (Plain ins) = LineBreak `notElem` ins
       needsBreak _ = True
-blockToXml (Header _ _) = -- should never happen, see renderSections
+blockToXml (Header _ _ _) = -- should never happen, see renderSections
                           error "unexpected header in section text"
 blockToXml HorizontalRule = return
                             [ el "empty-line" ()
@@ -413,7 +413,7 @@ indent = indentBlock
     let s' = unlines . map (spacer++) . lines $ s
     in  CodeBlock a s'
   indentBlock (BlockQuote bs) = BlockQuote (map indent bs)
-  indentBlock (Header l ins) = Header l (indentLines ins)
+  indentBlock (Header l attr' ins) = Header l attr' (indentLines ins)
   indentBlock everythingElse = everythingElse
   -- indent every (explicit) line
   indentLines :: [Inline] -> [Inline]
@@ -613,4 +613,4 @@ cMap = concatMap
 
 -- | Monadic equivalent of 'concatMap'.
 cMapM :: (Monad m) => (a -> m [b]) -> [a] -> m [b]
-cMapM f xs = concat `liftM` mapM f xs
\ No newline at end of file
+cMapM f xs = concat `liftM` mapM f xs
diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
index 68a8a1e09..2d42dd24e 100644
--- a/src/Text/Pandoc/Writers/HTML.hs
+++ b/src/Text/Pandoc/Writers/HTML.hs
@@ -219,7 +219,10 @@ inTemplate opts tit auths authsMeta date toc body' newvars =
 
 -- | Like Text.XHtml's identifier, but adds the writerIdentifierPrefix
 prefixedId :: WriterOptions -> String -> Attribute
-prefixedId opts s = A.id $ toValue $ writerIdentifierPrefix opts ++ s
+prefixedId opts s =
+  case s of
+    ""       -> mempty
+    _        -> A.id $ toValue $ writerIdentifierPrefix opts ++ s
 
 -- | Replacement for Text.XHtml's unordList.
 unordList :: WriterOptions -> ([Html] -> Html)
@@ -258,7 +261,10 @@ elementToListItem opts (Sec lev num id' headerText subsecs)
   let subList = if null subHeads
                    then mempty
                    else unordList opts subHeads
-  return $ Just $ (H.a ! A.href (toValue $ "#" ++ writerIdentifierPrefix opts ++ id')
+  return $ Just
+         $ if null id'
+              then (H.a $ toHtml txt) >> subList
+              else (H.a ! A.href (toValue $ "#" ++ writerIdentifierPrefix opts ++ id')
                        $ toHtml txt) >> subList
 elementToListItem _ _ = return Nothing
 
@@ -273,7 +279,7 @@ elementToHtml slideLevel opts (Sec level num id' title' elements) = do
   let titleSlide = slide && level < slideLevel
   header' <- if title' == [Str "\0"]  -- marker for hrule
                 then return mempty
-                else blockToHtml opts (Header level' title')
+                else blockToHtml opts (Header level' (id',[],[]) title')
   let isSec (Sec _ _ _ _ _) = True
       isSec (Blk _)         = False
   innerContents <- mapM (elementToHtml slideLevel opts)
@@ -283,8 +289,7 @@ elementToHtml slideLevel opts (Sec level num id' title' elements) = do
                         else elements
   let header'' = if (writerSectionDivs opts ||
                      writerSlideVariant opts == S5Slides ||
-                     slide ||
-                     not (isEnabled Ext_header_identifiers opts))
+                     slide)
                     then header'
                     else header' ! prefixedId opts id'
   let inNl x = mconcat $ nl opts : intersperse (nl opts) x ++ [nl opts]
@@ -442,15 +447,16 @@ blockToHtml opts (BlockQuote blocks) =
      else do
        contents <- blockListToHtml opts blocks
        return $ H.blockquote $ nl opts >> contents >> nl opts
-blockToHtml opts (Header level lst) = do
+blockToHtml opts (Header level (ident,_,_) lst) = do
   contents <- inlineListToHtml opts lst
   secnum <- liftM stSecNum get
   let contents' = if writerNumberSections opts
                      then (H.span ! A.class_ "header-section-number" $ toHtml $ showSecNum secnum) >>
                             strToHtml " " >> contents
                      else contents
-  let contents''  = if writerTableOfContents opts
-                       then H.a ! A.href (toValue $ "#" ++ writerIdentifierPrefix opts ++ "TOC") $ contents'
+  let contents''  = if writerTableOfContents opts && not (null ident)
+                       then H.a ! A.href (toValue $
+                              '#' : writerIdentifierPrefix opts ++ ident) $ contents'
                        else contents'
   return $ (case level of
               1 -> H.h1 contents''
diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index f86eb079a..f01ddac78 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -109,8 +109,8 @@ pandocToLaTeX options (Pandoc (Meta title authors date) blocks) = do
   let (blocks', lastHeader) = if writerCiteMethod options == Citeproc then
                                 (blocks, [])
                               else case last blocks of
-                                Header 1 il -> (init blocks, il)
-                                _           -> (blocks, [])
+                                Header 1 _ il -> (init blocks, il)
+                                _             -> (blocks, [])
   blocks'' <- if writerBeamer options
                  then toSlides blocks'
                  else return blocks'
@@ -227,7 +227,7 @@ toSlides bs = do
 
 elementToBeamer :: Int -> Element -> State WriterState [Block]
 elementToBeamer _slideLevel (Blk b) = return [b]
-elementToBeamer slideLevel  (Sec lvl _num _ident tit elts)
+elementToBeamer slideLevel  (Sec lvl _num ident tit elts)
   | lvl >  slideLevel = do
       bs <- concat `fmap` mapM (elementToBeamer slideLevel) elts
       return $ Para ( RawInline "latex" "\\begin{block}{"
@@ -235,7 +235,7 @@ elementToBeamer slideLevel  (Sec lvl _num _ident tit elts)
              : bs ++ [RawBlock "latex" "\\end{block}"]
   | lvl <  slideLevel = do
       bs <- concat `fmap` mapM (elementToBeamer slideLevel) elts
-      return $ (Header lvl tit) : bs
+      return $ (Header lvl (ident,[],[]) tit) : bs
   | otherwise = do -- lvl == slideLevel
       -- note: [fragile] is required or verbatim breaks
       let hasCodeBlock (CodeBlock _ _) = [True]
@@ -404,7 +404,7 @@ blockToLaTeX (DefinitionList lst) = do
                "\\end{description}"
 blockToLaTeX HorizontalRule = return $
   "\\begin{center}\\rule{3in}{0.4pt}\\end{center}"
-blockToLaTeX (Header level lst) = sectionHeader "" level lst
+blockToLaTeX (Header level (id',_,_) lst) = sectionHeader id' level lst
 blockToLaTeX (Table caption aligns widths heads rows) = do
   modify $ \s -> s{ stInTable = True, stTableNotes = [] }
   headers <- if all null heads
diff --git a/src/Text/Pandoc/Writers/Man.hs b/src/Text/Pandoc/Writers/Man.hs
index 10ca961f8..d5e44e71a 100644
--- a/src/Text/Pandoc/Writers/Man.hs
+++ b/src/Text/Pandoc/Writers/Man.hs
@@ -161,7 +161,7 @@ blockToMan opts (Para inlines) = do
 blockToMan _ (RawBlock "man" str) = return $ text str
 blockToMan _ (RawBlock _ _) = return empty
 blockToMan _ HorizontalRule = return $ text ".PP" $$ text "   *   *   *   *   *"
-blockToMan opts (Header level inlines) = do
+blockToMan opts (Header level _ inlines) = do
   contents <- inlineListToMan opts inlines
   let heading = case level of
                   1 -> ".SH "
diff --git a/src/Text/Pandoc/Writers/Markdown.hs b/src/Text/Pandoc/Writers/Markdown.hs
index 384851c91..adefbb2b5 100644
--- a/src/Text/Pandoc/Writers/Markdown.hs
+++ b/src/Text/Pandoc/Writers/Markdown.hs
@@ -274,7 +274,7 @@ blockToMarkdown opts (RawBlock f str)
 blockToMarkdown _ (RawBlock _ _) = return empty
 blockToMarkdown _ HorizontalRule =
   return $ blankline <> text "* * * * *" <> blankline
-blockToMarkdown opts (Header level inlines) = do
+blockToMarkdown opts (Header level attr inlines) = do
   contents <- inlineListToMarkdown opts inlines
   st <- get
   let setext = writerSetextHeaders opts
diff --git a/src/Text/Pandoc/Writers/MediaWiki.hs b/src/Text/Pandoc/Writers/MediaWiki.hs
index 01fc49a10..a71d7ee7e 100644
--- a/src/Text/Pandoc/Writers/MediaWiki.hs
+++ b/src/Text/Pandoc/Writers/MediaWiki.hs
@@ -104,7 +104,7 @@ blockToMediaWiki _ (RawBlock _ _) = return ""
 
 blockToMediaWiki _ HorizontalRule = return "\n-----\n"
 
-blockToMediaWiki opts (Header level inlines) = do
+blockToMediaWiki opts (Header level _ inlines) = do
   contents <- inlineListToMediaWiki opts inlines
   let eqs = replicate level '='
   return $ eqs ++ " " ++ contents ++ " " ++ eqs ++ "\n"
diff --git a/src/Text/Pandoc/Writers/OpenDocument.hs b/src/Text/Pandoc/Writers/OpenDocument.hs
index 027ddfda1..b59e096c9 100644
--- a/src/Text/Pandoc/Writers/OpenDocument.hs
+++ b/src/Text/Pandoc/Writers/OpenDocument.hs
@@ -287,7 +287,7 @@ blockToOpenDocument :: WriterOptions -> Block -> State WriterState Doc
 blockToOpenDocument o bs
     | Plain          b <- bs = inParagraphTags =<< inlinesToOpenDocument o b
     | Para           b <- bs = inParagraphTags =<< inlinesToOpenDocument o b
-    | Header       i b <- bs = setFirstPara >>
+    | Header     i _ b <- bs = setFirstPara >>
                                (inHeaderTags  i =<< inlinesToOpenDocument o b)
     | BlockQuote     b <- bs = setFirstPara >> mkBlockQuote b
     | DefinitionList b <- bs = setFirstPara >> defList b
diff --git a/src/Text/Pandoc/Writers/Org.hs b/src/Text/Pandoc/Writers/Org.hs
index 86b570c30..894d4afa0 100644
--- a/src/Text/Pandoc/Writers/Org.hs
+++ b/src/Text/Pandoc/Writers/Org.hs
@@ -131,7 +131,7 @@ blockToOrg (RawBlock f str) | f == "org" || f == "latex" || f == "tex" =
   return $ text str
 blockToOrg (RawBlock _ _) = return empty
 blockToOrg HorizontalRule = return $ blankline $$ "--------------" $$ blankline
-blockToOrg (Header level inlines) = do
+blockToOrg (Header level _ inlines) = do
   contents <- inlineListToOrg inlines
   let headerStr = text $ if level > 999 then " " else replicate level '*'
   return $ headerStr <> " " <> contents <> blankline
diff --git a/src/Text/Pandoc/Writers/RST.hs b/src/Text/Pandoc/Writers/RST.hs
index 40939c6b7..85ca98f5a 100644
--- a/src/Text/Pandoc/Writers/RST.hs
+++ b/src/Text/Pandoc/Writers/RST.hs
@@ -161,7 +161,7 @@ blockToRST (RawBlock f str) =
            (nest 3 $ text str) $$ blankline
 blockToRST HorizontalRule =
   return $ blankline $$ "--------------" $$ blankline
-blockToRST (Header level inlines) = do
+blockToRST (Header level _ inlines) = do
   contents <- inlineListToRST inlines
   let headerChar = if level > 5 then ' ' else "=-~^'" !! (level - 1)
   let border = text $ replicate (offset contents) headerChar
diff --git a/src/Text/Pandoc/Writers/RTF.hs b/src/Text/Pandoc/Writers/RTF.hs
index 619e7086f..f2a271c1d 100644
--- a/src/Text/Pandoc/Writers/RTF.hs
+++ b/src/Text/Pandoc/Writers/RTF.hs
@@ -72,7 +72,7 @@ writeRTF options (Pandoc (Meta title authors date) blocks) =
       datetext = inlineListToRTF date
       spacer = not $ all null $ titletext : datetext : authorstext
       body = concatMap (blockToRTF 0 AlignDefault) blocks
-      isTOCHeader (Header lev _) = lev <= writerTOCDepth options
+      isTOCHeader (Header lev _ _) = lev <= writerTOCDepth options
       isTOCHeader _ = False
       context = writerVariables options ++
                 [ ("body", body)
@@ -91,7 +91,7 @@ tableOfContents :: [Block] -> String
 tableOfContents headers =
   let contentsTree = hierarchicalize headers
   in  concatMap (blockToRTF 0 AlignDefault) $
-      [Header 1 [Str "Contents"],
+      [Header 1 nullAttr [Str "Contents"],
        BulletList (map elementToListItem contentsTree)]
 
 elementToListItem :: Element -> [Block]
@@ -208,7 +208,7 @@ blockToRTF indent alignment (DefinitionList lst) = spaceAtEnd $
   concatMap (definitionListItemToRTF alignment indent) lst
 blockToRTF indent _ HorizontalRule =
   rtfPar indent 0 AlignCenter "\\emdash\\emdash\\emdash\\emdash\\emdash"
-blockToRTF indent alignment (Header level lst) = rtfPar indent 0 alignment $
+blockToRTF indent alignment (Header level _ lst) = rtfPar indent 0 alignment $
   "\\b \\fs" ++ (show (40 - (level * 4))) ++ " " ++ inlineListToRTF lst
 blockToRTF indent alignment (Table caption aligns sizes headers rows) =
   (if all null headers
diff --git a/src/Text/Pandoc/Writers/Texinfo.hs b/src/Text/Pandoc/Writers/Texinfo.hs
index 4c29b410d..03e08c463 100644
--- a/src/Text/Pandoc/Writers/Texinfo.hs
+++ b/src/Text/Pandoc/Writers/Texinfo.hs
@@ -64,7 +64,7 @@ writeTexinfo options document =
 -- | Add a "Top" node around the document, needed by Texinfo.
 wrapTop :: Pandoc -> Pandoc
 wrapTop (Pandoc (Meta title authors date) blocks) =
-  Pandoc (Meta title authors date) (Header 0 title : blocks)
+  Pandoc (Meta title authors date) (Header 0 nullAttr title : blocks)
 
 pandocToTexinfo :: WriterOptions -> Pandoc -> State WriterState String
 pandocToTexinfo options (Pandoc (Meta title authors date) blocks) = do
@@ -195,14 +195,14 @@ blockToTexinfo HorizontalRule =
 	     text (take 72 $ repeat '-') $$
              text "@end ifnottex"
 
-blockToTexinfo (Header 0 lst) = do
+blockToTexinfo (Header 0 _ lst) = do
   txt <- if null lst
             then return $ text "Top"
             else inlineListToTexinfo lst
   return $ text "@node Top" $$
            text "@top " <> txt <> blankline
 
-blockToTexinfo (Header level lst) = do
+blockToTexinfo (Header level _ lst) = do
   node <- inlineListForNode lst
   txt <- inlineListToTexinfo lst
   idsUsed <- gets stIdentifiers
@@ -286,7 +286,7 @@ blockListToTexinfo [] = return empty
 blockListToTexinfo (x:xs) = do
   x' <- blockToTexinfo x
   case x of
-    Header level _ -> do
+    Header level _ _ -> do
       -- We need need to insert a menu for this node.
       let (before, after) = break isHeader xs
       before' <- blockListToTexinfo before
@@ -311,14 +311,14 @@ blockListToTexinfo (x:xs) = do
       return $ x' $$ xs'
 
 isHeader :: Block -> Bool
-isHeader (Header _ _) = True
-isHeader _            = False
+isHeader (Header _ _ _) = True
+isHeader _              = False
 
 collectNodes :: Int -> [Block] -> [Block]
 collectNodes _ [] = []
 collectNodes level (x:xs) =
   case x of
-    (Header hl _) ->
+    (Header hl _ _) ->
       if hl < level
          then []
          else if hl == level
@@ -329,7 +329,7 @@ collectNodes level (x:xs) =
 
 makeMenuLine :: Block
              -> State WriterState Doc
-makeMenuLine (Header _ lst) = do
+makeMenuLine (Header _ _ lst) = do
   txt <- inlineListForNode lst
   return $ text "* " <> txt <> text "::"
 makeMenuLine _ = error "makeMenuLine called with non-Header block"
diff --git a/src/Text/Pandoc/Writers/Textile.hs b/src/Text/Pandoc/Writers/Textile.hs
index 44fdc7efb..1f5d3e79d 100644
--- a/src/Text/Pandoc/Writers/Textile.hs
+++ b/src/Text/Pandoc/Writers/Textile.hs
@@ -121,9 +121,10 @@ blockToTextile _ (RawBlock f str) =
 
 blockToTextile _ HorizontalRule = return "<hr />\n"
 
-blockToTextile opts (Header level inlines) = do
+blockToTextile opts (Header level (ident,_,_) inlines) = do
   contents <- inlineListToTextile opts inlines
-  let prefix = 'h' : (show level ++ ". ")
+  let attribs = if null ident then "" else "(#" ++ ident ++ ")"
+  let prefix = 'h' : show level ++ attribs ++ ". "
   return $ prefix ++ contents ++ "\n"
 
 blockToTextile _ (CodeBlock (_,classes,_) str) | any (all isSpace) (lines str) =