Use new flexible metadata type.

* Depend on pandoc 1.12.
* Added yaml dependency.
* `Text.Pandoc.XML`: Removed `stripTags`.  (API change.)
* `Text.Pandoc.Shared`:  Added `metaToJSON`.
  This will be used in writers to create a JSON object for use
  in the templates from the pandoc metadata.
* Revised readers and writers to use the new Meta type.
* `Text.Pandoc.Options`: Added `Ext_yaml_title_block`.
* Markdown reader:  Added support for YAML metadata block.
  Note that it must come at the beginning of the document.
* `Text.Pandoc.Parsing.ParserState`:  Replace `stateTitle`,
  `stateAuthors`, `stateDate` with `stateMeta`.
* RST reader:  Improved metadata.
  Treat initial field list as metadata when standalone specified.
  Previously ALL fields "title", "author", "date" in field lists
  were treated as metadata, even if not at the beginning.
  Use `subtitle` metadata field for subtitle.
* `Text.Pandoc.Templates`:  Export `renderTemplate'` that takes a string
  instead of a compiled template..
* OPML template:  Use 'for' loop for authors.
* Org template: '#+TITLE:' is inserted before the title.
  Previously the writer did this.

1 files changed, 22 insertions, 27 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index f3f76ce5c..0d4afb2a7 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -65,13 +65,11 @@ parseLaTeX = do
   bs <- blocks
   eof
   st <- getState
-  let title' = stateTitle st
-  let authors' = stateAuthors st
-  let date' = stateDate st
+  let meta = stateMeta st
   refs <- getOption readerReferences
   mbsty <- getOption readerCitationStyle
-  return $ processBiblio mbsty refs
-         $ Pandoc (Meta title' authors' date') $ toList bs
+  let (Pandoc _ bs') = processBiblio mbsty refs $ doc bs
+  return $ Pandoc meta bs'
 
 type LP = Parser [Char] ParserState
 
@@ -249,13 +247,13 @@ ignoreBlocks name = (name, doraw <|> (mempty <$ optargs))
 blockCommands :: M.Map String (LP Blocks)
 blockCommands = M.fromList $
   [ ("par", mempty <$ skipopts)
-  , ("title", mempty <$ (skipopts *> tok >>= addTitle))
-  , ("subtitle", mempty <$ (skipopts *> tok >>= addSubtitle))
+  , ("title", mempty <$ (skipopts *> tok >>= addMeta "title"))
+  , ("subtitle", mempty <$ (skipopts *> tok >>= addMeta "subtitle"))
   , ("author", mempty <$ (skipopts *> authors))
   -- -- in letter class, temp. store address & sig as title, author
-  , ("address", mempty <$ (skipopts *> tok >>= addTitle))
+  , ("address", mempty <$ (skipopts *> tok >>= addMeta "address"))
   , ("signature", mempty <$ (skipopts *> authors))
-  , ("date", mempty <$ (skipopts *> tok >>= addDate))
+  , ("date", mempty <$ (skipopts *> tok >>= addMeta "date"))
   -- sectioning
   , ("chapter", updateState (\s -> s{ stateHasChapters = True })
                       *> section nullAttr 0)
@@ -301,12 +299,8 @@ blockCommands = M.fromList $
   , "hspace", "vspace"
   ]
 
-addTitle :: Inlines -> LP ()
-addTitle tit = updateState (\s -> s{ stateTitle = toList tit })
-
-addSubtitle :: Inlines -> LP ()
-addSubtitle tit = updateState (\s -> s{ stateTitle = stateTitle s ++
-                        toList (str ":" <> linebreak <> tit) })
+addMeta :: ToMetaValue a => String -> a -> LP ()
+addMeta field val = updateState $ setMeta field val
 
 authors :: LP ()
 authors = try $ do
@@ -317,10 +311,7 @@ authors = try $ do
                -- skip e.g. \vspace{10pt}
   auths <- sepBy oneAuthor (controlSeq "and")
   char '}'
-  updateState (\s -> s { stateAuthors = map (normalizeSpaces . toList) auths })
-
-addDate :: Inlines -> LP ()
-addDate dat = updateState (\s -> s{ stateDate = toList dat })
+  addMeta "authors" (map trimInlines auths)
 
 section :: Attr -> Int -> LP Blocks
 section attr lvl = do
@@ -872,20 +863,24 @@ letter_contents = do
   bs <- blocks
   st <- getState
   -- add signature (author) and address (title)
-  let addr = case stateTitle st of
-                  []   -> mempty
-                  x    -> para $ trimInlines $ fromList x
-  updateState $ \s -> s{ stateAuthors = [], stateTitle = [] }
+  let addr = case lookupMeta "address" (stateMeta st) of
+                  Just (MetaBlocks [Plain xs]) ->
+                     para $ trimInlines $ fromList xs
+                  _ -> mempty
   return $ addr <> bs -- sig added by \closing
 
 closing :: LP Blocks
 closing = do
   contents <- tok
   st <- getState
-  let sigs = case stateAuthors st of
-                  []   -> mempty
-                  xs   -> para $ trimInlines $ fromList
-                               $ intercalate [LineBreak] xs
+  let extractInlines (MetaBlocks [Plain ys]) = ys
+      extractInlines (MetaBlocks [Para ys ]) = ys
+      extractInlines _          = []
+  let sigs = case lookupMeta "author" (stateMeta st) of
+                  Just (MetaList xs) ->
+                    para $ trimInlines $ fromList $
+                      intercalate [LineBreak] $ map extractInlines xs
+                  _ -> mempty
   return $ para (trimInlines contents) <> sigs
 
 item :: LP Blocks