Typst reader: don't include metadata from document element.

The problem is that typst doesn't print this metadata; it is only
used in PDF properties. The title, authors, and so on are represented
in the typst document (and there is no standardized method like
LaTeX's `\maketitle`).  So if we parse this as metadata then converting
a typst document will likely lead to a double title.

1 files changed, 33 insertions, 27 deletions

diff --git a/src/Text/Pandoc/Readers/Typst.hs b/src/Text/Pandoc/Readers/Typst.hs
index 3b9d5b7cb..b0be897da 100644
--- a/src/Text/Pandoc/Readers/Typst.hs
+++ b/src/Text/Pandoc/Readers/Typst.hs
@@ -131,33 +131,39 @@ pPandoc :: PandocMonad m => P m B.Pandoc
 pPandoc = do
   Elt "document" _ fields <- pTok isDocument
   bs <- getField "body" fields >>= pWithContents pBlocks
-  title <- (getField "title" fields >>= pWithContents pInlines) <|>
-              pure mempty
-  authors <- (getField "author" fields >>=
-                          mapM (pWithContents pInlines) . V.toList) <|>
-             ((:[]) <$> (getField "author" fields >>=
-                           (\x -> guard (not (null x)) *>
-                             pWithContents pInlines x))) <|>
-              pure []
-  date <- (getField "date" fields >>= pWithContents pInlines) <|>
-              pure mempty
-  keywords <- (getField "keywords" fields >>=
-                 mapM (pWithContents pInlines) . V.toList)
-                <|> pure []
-  pure $
-    (if title == mempty
-        then id
-        else B.setMeta "title" title) .
-    (if null authors
-        then id
-        else B.setMeta "author" authors) .
-    (if null date
-        then id
-        else B.setMeta "date" date) .
-    (if null keywords
-        then id
-        else B.setMeta "keywords" keywords) $
-    B.doc bs
+  pure $ B.doc bs
+  -- The following alternative code would add metadata from the
+  -- fields on the document element. It is commented out because
+  -- the typst metadata doesn't print anything by default, in contrast
+  -- to pandoc with its usual templates.  Hence, with this code,
+  -- converting a typst document might yield a double title, author, etc.
+  --
+  -- title <- (getField "title" fields >>= pWithContents pInlines) <|>
+  --             pure mempty
+  -- authors <- (getField "author" fields >>=
+  --                         mapM (pWithContents pInlines) . V.toList) <|>
+  --            ((:[]) <$> (getField "author" fields >>=
+  --                          (\x -> guard (not (null x)) *>
+  --                            pWithContents pInlines x))) <|>
+  --             pure []
+  -- date <- (getField "date" fields >>= pWithContents pInlines) <|>
+  --             pure mempty
+  -- keywords <- (getField "keywords" fields >>=
+  --                mapM (pWithContents pInlines) . V.toList)
+  --               <|> pure []
+  -- pure $
+  --   (if title == mempty
+  --       then id
+  --       else B.setMeta "title" title) .
+  --   (if null authors
+  --       then id
+  --       else B.setMeta "author" authors) .
+  --   (if null date
+  --       then id
+  --       else B.setMeta "date" date) .
+  --   (if null keywords
+  --       then id
+  --       else B.setMeta "keywords" keywords) $ B.doc bs
 
 pBlocks :: PandocMonad m => P m B.Blocks
 pBlocks = mconcat <$> many pBlock