Add option for top-level division type

The `--chapters` option is replaced with `--top-level-division` which allows
users to specify the type as which top-level headers should be output. Possible
values are `section` (the default), `chapter`, or `part`.

The formats LaTeX, ConTeXt, and Docbook allow `part` as top-level division, TEI
only allows to set the `type` attribute on `div` containers.  The writers are
altered to respect this option in a sensible way.

5 files changed, 71 insertions, 48 deletions

diff --git a/src/Text/Pandoc/Options.hs b/src/Text/Pandoc/Options.hs
index 856fa259f..575250b9e 100644
--- a/src/Text/Pandoc/Options.hs
+++ b/src/Text/Pandoc/Options.hs
@@ -43,6 +43,7 @@ module Text.Pandoc.Options ( Extension(..)
                            , HTMLSlideVariant (..)
                            , EPUBVersion (..)
                            , WrapOption (..)
+                           , Division (..)
                            , WriterOptions (..)
                            , TrackChanges (..)
                            , ReferenceLocation (..)
@@ -337,6 +338,12 @@ data WrapOption = WrapAuto        -- ^ Automatically wrap to width
                 | WrapPreserve    -- ^ Preserve wrapping of input source
                 deriving (Show, Read, Eq, Data, Typeable, Generic)
 
+-- | Options defining the type of top-level headers.
+data Division = Part              -- ^ Top-level headers become parts
+              | Chapter           -- ^ Top-level headers become chapters
+              | Section           -- ^ Top-level headers become sections
+              deriving (Show, Read, Eq, Ord, Data, Typeable, Generic)
+
 -- | Locations for footnotes and references in markdown output
 data ReferenceLocation = EndOfBlock    -- ^ End of block
                        | EndOfSection  -- ^ prior to next section header (or end of document)
@@ -373,8 +380,7 @@ data WriterOptions = WriterOptions
   , writerHtmlQTags        :: Bool       -- ^ Use @<q>@ tags for quotes in HTML
   , writerBeamer           :: Bool       -- ^ Produce beamer LaTeX slide show
   , writerSlideLevel       :: Maybe Int  -- ^ Force header level of slides
-  , writerChapters         :: Bool       -- ^ Use "chapter" for top-level sects
-  , writerParts            :: Bool       -- ^ Use "part" for top-level sects in LaTeX
+  , writerTopLevelDivision :: Division   -- ^ Type of top-level divisions
   , writerListings         :: Bool       -- ^ Use listings package for code
   , writerHighlight        :: Bool       -- ^ Highlight source code
   , writerHighlightStyle   :: Style      -- ^ Style to use for highlighting
@@ -422,8 +428,7 @@ instance Default WriterOptions where
                       , writerHtmlQTags        = False
                       , writerBeamer           = False
                       , writerSlideLevel       = Nothing
-                      , writerChapters         = False
-                      , writerParts            = False
+                      , writerTopLevelDivision = Section
                       , writerListings         = False
                       , writerHighlight        = False
                       , writerHighlightStyle   = pygments
diff --git a/src/Text/Pandoc/Writers/ConTeXt.hs b/src/Text/Pandoc/Writers/ConTeXt.hs
index 398d4170f..6d66ce48c 100644
--- a/src/Text/Pandoc/Writers/ConTeXt.hs
+++ b/src/Text/Pandoc/Writers/ConTeXt.hs
@@ -83,9 +83,10 @@ pandocToConTeXt options (Pandoc meta blocks) = do
                               ]
   let context =   defField "toc" (writerTableOfContents options)
                 $ defField "placelist" (intercalate ("," :: String) $
-                     take (writerTOCDepth options + if writerChapters options
-                                                       then 0
-                                                       else 1)
+                     take (writerTOCDepth options +
+                           if writerTopLevelDivision options < Section
+                           then 0
+                           else 1)
                        ["chapter","section","subsection","subsubsection",
                         "subsubsubsection","subsubsubsubsection"])
                 $ defField "body" main
@@ -412,7 +413,7 @@ inlineToConTeXt (Span (_,_,kvs) ils) = do
                        Nothing -> txt
   fmap (wrapLang . wrapDir) $ inlineListToConTeXt ils
 
--- | Craft the section header, inserting the secton reference, if supplied.
+-- | Craft the section header, inserting the section reference, if supplied.
 sectionHeader :: Attr
               -> Int
               -> [Inline]
@@ -421,21 +422,26 @@ sectionHeader (ident,classes,_) hdrLevel lst = do
   contents <- inlineListToConTeXt lst
   st <- get
   let opts = stOptions st
-  let level' = if writerChapters opts then hdrLevel - 1 else hdrLevel
+  let level' = case writerTopLevelDivision opts of
+                 Part    -> hdrLevel - 2
+                 Chapter -> hdrLevel - 1
+                 Section -> hdrLevel
   let ident' = toLabel ident
   let (section, chapter) = if "unnumbered" `elem` classes
                               then (text "subject", text "title")
                               else (text "section", text "chapter")
-  return $ if level' >= 1 && level' <= 5
-               then char '\\'
-                    <> text (concat (replicate (level' - 1) "sub"))
-                    <> section
-                    <> (if (not . null) ident' then brackets (text ident') else empty)
-                    <> braces contents
-                    <> blankline
-               else if level' == 0
-                       then char '\\' <> chapter <> braces contents
-                       else contents <> blankline
+  return $ case level' of
+             -1                   -> text "\\part" <> braces contents
+             0                    -> char '\\' <> chapter <> braces contents
+             n | n >= 1 && n <= 5 -> char '\\'
+                                     <> text (concat (replicate (n - 1) "sub"))
+                                     <> section
+                                     <> (if (not . null) ident'
+                                         then brackets (text ident')
+                                         else empty)
+                                     <> braces contents
+                                     <> blankline
+             _                    -> contents <> blankline
 
 fromBcp47' :: String -> String
 fromBcp47' = fromBcp47 . splitBy (=='-')
diff --git a/src/Text/Pandoc/Writers/Docbook.hs b/src/Text/Pandoc/Writers/Docbook.hs
index e19b4666b..c28056153 100644
--- a/src/Text/Pandoc/Writers/Docbook.hs
+++ b/src/Text/Pandoc/Writers/Docbook.hs
@@ -79,12 +79,16 @@ writeDocbook opts (Pandoc meta blocks) =
       colwidth = if writerWrapText opts == WrapAuto
                     then Just $ writerColumns opts
                     else Nothing
-      render' = render colwidth
-      opts' = if "/book>" `isSuffixOf`
-                      (trimr $ writerTemplate opts)
-                 then opts{ writerChapters = True }
-                 else opts
-      startLvl = if writerChapters opts' then 0 else 1
+      render'  = render colwidth
+      opts'    = if ("/book>" `isSuffixOf` (trimr $ writerTemplate opts) &&
+                     writerTopLevelDivision opts >= Section)
+                    then opts{ writerTopLevelDivision = Chapter }
+                    else opts
+      -- The numbering here follows LaTeX's internal numbering
+      startLvl = case writerTopLevelDivision opts' of
+                   Part    -> -1
+                   Chapter -> 0
+                   Section -> 1
       auths'   = map (authorToDocbook opts) $ docAuthors meta
       meta'    = B.setMeta "author" auths' meta
       Just metadata = metaToJSON opts
@@ -111,11 +115,12 @@ elementToDocbook opts lvl (Sec _ _num (id',_,_) title elements) =
                     then [Blk (Para [])]
                     else elements
       tag = case lvl of
-                 n | n == 0           -> "chapter"
-                   | n >= 1 && n <= 5 -> if writerDocbook5 opts
+                 -1                   -> "part"
+                 0                    -> "chapter"
+                 n | n >= 1 && n <= 5 -> if writerDocbook5 opts
                                               then "section"
                                               else "sect" ++ show n
-                   | otherwise        -> "simplesect"
+                 _                    -> "simplesect"
       idAttr = [("id", writerIdentifierPrefix opts ++ id') | not (null id')]
       nsAttr = if writerDocbook5 opts && lvl == 0 then [("xmlns", "http://docbook.org/ns/docbook"),("xmlns:xlink", "http://www.w3.org/1999/xlink")]
                                       else []
diff --git a/src/Text/Pandoc/Writers/LaTeX.hs b/src/Text/Pandoc/Writers/LaTeX.hs
index 33e4ffbb1..0fd8cdd8c 100644
--- a/src/Text/Pandoc/Writers/LaTeX.hs
+++ b/src/Text/Pandoc/Writers/LaTeX.hs
@@ -87,7 +87,8 @@ writeLaTeX options document =
                 stOptions = options, stVerbInNote = False,
                 stTable = False, stStrikeout = False,
                 stUrl = False, stGraphics = False,
-                stLHS = False, stBook = writerChapters options,
+                stLHS = False,
+                stBook = writerTopLevelDivision options < Section,
                 stCsquotes = False, stHighlighting = False,
                 stIncremental = writerIncremental options,
                 stInternalLinks = [], stUsesEuro = False }
@@ -750,25 +751,26 @@ sectionHeader unnumbered ident level lst = do
                          <> braces (text plain))
   book <- gets stBook
   opts <- gets stOptions
-  let level' = case level of
-                 1 | writerParts opts            -> 0
-                   | writerBeamer opts           -> 0
-                   | book || writerChapters opts -> 1
-                   | otherwise                   -> 2
-                 _ | writerParts opts            -> level - 1
-                   | book || writerChapters opts -> level
-                   | otherwise                   -> level + 1
+  let topLevelDivision = min (if book then Chapter else Section)
+                             (writerTopLevelDivision opts)
+  let level' = if writerBeamer opts && topLevelDivision < Section
+               -- beamer has parts but no chapters
+               then if level == 1 then -1 else level - 1
+               else case topLevelDivision of
+                 Part    -> level - 2
+                 Chapter -> level - 1
+                 Section -> level
   let sectionType = case level' of
-                          0  -> "part"
-                          1  -> "chapter"
-                          2  -> "section"
-                          3  -> "subsection"
-                          4  -> "subsubsection"
-                          5  -> "paragraph"
-                          6  -> "subparagraph"
+                          -1 -> "part"
+                          0  -> "chapter"
+                          1  -> "section"
+                          2  -> "subsection"
+                          3  -> "subsubsection"
+                          4  -> "paragraph"
+                          5  -> "subparagraph"
                           _  -> ""
   inQuote <- gets stInQuote
-  let prefix = if inQuote && level' >= 5
+  let prefix = if inQuote && level' >= 4
                   then text "\\mbox{}%"
                   -- needed for \paragraph, \subparagraph in quote environment
                   -- see http://tex.stackexchange.com/questions/169830/
@@ -777,7 +779,7 @@ sectionHeader unnumbered ident level lst = do
   let star = if unnumbered && level < 4 then text "*" else empty
   let stuffing = star <> optional <> contents
   stuffing' <- hypertarget ident $ text ('\\':sectionType) <> stuffing <> lab
-  return $ if level' > 6
+  return $ if level' > 5
               then txt
               else prefix $$ stuffing'
                    $$ if unnumbered
diff --git a/src/Text/Pandoc/Writers/TEI.hs b/src/Text/Pandoc/Writers/TEI.hs
index 076c1ae3a..6120330ca 100644
--- a/src/Text/Pandoc/Writers/TEI.hs
+++ b/src/Text/Pandoc/Writers/TEI.hs
@@ -60,7 +60,10 @@ writeTEI opts (Pandoc meta blocks) =
                     then Just $ writerColumns opts
                     else Nothing
       render' = render colwidth
-      startLvl = if writerChapters opts then 0 else 1
+      startLvl = case writerTopLevelDivision opts of
+                   Part    -> -1
+                   Chapter -> 0
+                   Section -> 1
       auths'   = map (authorToTEI opts) $ docAuthors meta
       meta'    = B.setMeta "author" auths' meta
       Just metadata = metaToJSON opts
@@ -86,8 +89,10 @@ elementToTEI opts lvl (Sec _ _num (id',_,_) title elements) =
   let elements' = if null elements
                     then [Blk (Para [])]
                     else elements
+      -- level numbering correspond to LaTeX internals
       divType = case lvl of
-                 n | n == 0           -> "chapter"
+                 n | n == -1          -> "part"
+                   | n == 0           -> "chapter"
                    | n >= 1 && n <= 5 -> "level" ++ show n
                    | otherwise        -> "section"
   in inTags True "div" [("type", divType) | not (null id')] $