T.P.Writers.Shared - add toTableOfContents (API change).

This is refactored out from the Markdown writer.
IT can be used in other writers to create a generic TOC.

src/Text/Pandoc/Writers/Markdown.hs

@@ -212,7 +212,8 @@ pandocToMarkdown opts (Pandoc meta blocks) = do
                         Nothing -> empty
   let headerBlocks = filter isHeaderBlock blocks
   toc <- if writerTableOfContents opts
-         then render' <$> tableOfContents opts headerBlocks
+         then render' <$> blockToMarkdown opts
+                            ( toTableOfContents opts $ headerBlocks )
          else return ""
   -- Strip off final 'references' header if markdown citations enabled
   let blocks' = if isEnabled Ext_citations opts
@@ -319,26 +320,6 @@ escapeString opts =
                    _            -> '.':go cs
        _   -> c : go cs
 
--- | Construct table of contents from list of header blocks.
-tableOfContents :: PandocMonad m => WriterOptions -> [Block] -> MD m Doc
-tableOfContents opts headers = do
-  contents <- BulletList <$> mapM (elementToListItem opts) (hierarchicalize headers)
-  blockToMarkdown opts contents
-
--- | Converts an Element to a list item for a table of contents,
-elementToListItem :: PandocMonad m => WriterOptions -> Element -> MD m [Block]
-elementToListItem opts (Sec lev _nums (ident,_,_) headerText subsecs)
-  = do isPlain <- asks envPlain
-       let headerLink = if null ident || isPlain
-                         then walk deNote headerText
-                         else [Link nullAttr (walk deNote headerText)
-                                 ('#':ident, "")]
-       listContents <- if null subsecs || lev >= writerTOCDepth opts
-                          then return []
-                          else mapM (elementToListItem opts) subsecs
-       return [Plain headerLink, BulletList listContents]
-elementToListItem _ (Blk _) = return []
-
 attrsToMarkdown :: Attr -> Doc
 attrsToMarkdown attribs = braces $ hsep [attribId, attribClasses, attribKeys]
         where attribId = case attribs of

src/Text/Pandoc/Writers/Shared.hs

@@ -49,6 +49,7 @@ module Text.Pandoc.Writers.Shared (
                      , stripLeadingTrailingSpace
                      , toSubscript
                      , toSuperscript
+                     , toTableOfContents
                      )
 where
 import Prelude
@@ -66,7 +67,8 @@ import qualified Text.Pandoc.Builder as Builder
 import Text.Pandoc.Definition
 import Text.Pandoc.Options
 import Text.Pandoc.Pretty
-import Text.Pandoc.Shared (stringify)
+import Text.Pandoc.Shared (stringify, hierarchicalize, Element(..), deNote)
+import Text.Pandoc.Walk (walk)
 import Text.Pandoc.UTF8 (toStringLazy)
 import Text.Pandoc.XML (escapeStringForXML)
 
@@ -412,3 +414,23 @@ toSubscript c
                  Just $ chr (0x2080 + (ord c - 48))
   | isSpace c = Just c
   | otherwise = Nothing
+
+-- | Construct table of contents (as a bullet list) from document body.
+toTableOfContents :: WriterOptions
+                  -> [Block]
+                  -> Block
+toTableOfContents opts bs =
+  BulletList $ map (elementToListItem opts) (hierarchicalize bs)
+
+-- | Converts an Element to a list item for a table of contents,
+elementToListItem :: WriterOptions -> Element -> [Block]
+elementToListItem opts (Sec lev _nums (ident,_,_) headerText subsecs)
+  = Plain headerLink : [BulletList listContents | not (null subsecs)
+                                                , lev < writerTOCDepth opts]
+ where
+   headerText' = walk deNote headerText
+   headerLink = if null ident
+                   then headerText'
+                   else [Link nullAttr headerText' ('#':ident, "")]
+   listContents = map (elementToListItem opts) subsecs
+elementToListItem _ (Blk _) = []