Typst reader: allow @refs to become citations...

if there is no corresponding label in the document.

Author: jgm

src/Text/Pandoc/Readers/Typst.hs

@@ -68,10 +68,13 @@ readTypst _opts inp = do
                   currentUTCTime = getCurrentTime,
                   lookupEnvVar = fmap (fmap T.unpack) . lookupEnv . T.pack,
                   checkExistence = fileExists }
-      evaluateTypst ops inputName parsed >>=
-                  either (throwError . PandocParseError . T.pack . show) pure >>=
-                  runParserT pPandoc () inputName . F.toList >>=
-                  either (throwError . PandocParseError . T.pack . show) pure
+      res <- evaluateTypst ops inputName parsed
+      case res of
+        Left e -> throwError $ PandocParseError $ tshow e
+        Right cs -> do
+          let labs = findLabels cs
+          runParserT pPandoc labs inputName (F.toList cs) >>=
+            either (throwError . PandocParseError . T.pack . show) pure
 
 pBlockElt :: PandocMonad m => P m B.Blocks
 pBlockElt = try $ do
@@ -98,13 +101,29 @@ pInline = try $ do
       | "math." `T.isPrefixOf` tname
       , tname /= "math.equation" ->
           B.math . writeTeX <$> pMathMany (Seq.singleton res)
-    Elt name@(Identifier tname) pos fields ->
-      case M.lookup name inlineHandlers of
-        Nothing -> do
-          ignored ("unknown inline element " <> tname <>
-                   " at " <> tshow pos)
-          pure mempty
-        Just handler -> handler Nothing fields
+    Elt name@(Identifier tname) pos fields -> do
+      labs <- getState
+      labelTarget <- (do VLabel t <- getField "target" fields
+                         True <$ guard (t `elem` labs))
+                  <|> pure False
+      if tname == "ref" && not labelTarget
+         then do
+           -- @foo is a citation unless it links to a lab in the doc:
+           let targetToKey (Identifier "target") = Identifier "key"
+               targetToKey k = k
+           case M.lookup "cite" inlineHandlers of
+             Nothing -> do
+               ignored ("unknown inline element " <> tname <>
+                        " at " <> tshow pos)
+               pure mempty
+             Just handler -> handler Nothing (M.mapKeys targetToKey fields)
+         else do
+          case M.lookup name inlineHandlers of
+            Nothing -> do
+              ignored ("unknown inline element " <> tname <>
+                       " at " <> tshow pos)
+              pure mempty
+            Just handler -> handler Nothing fields
 
 pPandoc :: PandocMonad m => P m B.Pandoc
 pPandoc = B.doc <$> pBlocks
@@ -547,3 +566,12 @@ collapseAdjacentCites = B.fromList . foldr go [] . B.toList
 modString :: (Text -> Text) -> B.Inline -> B.Inline
 modString f (B.Str t) = B.Str (f t)
 modString _ x = x
+
+findLabels :: Seq.Seq Content -> [Text]
+findLabels = foldr go []
+ where
+   go (Txt{}) = id
+   go (Lab t) = (t :)
+   go (Elt{ eltFields = fs }) = \ts -> foldr go' ts fs
+   go' (VContent cs) = (findLabels cs ++)
+   go' _ = id

src/Text/Pandoc/Readers/Typst/Parsing.hs

@@ -26,7 +26,8 @@ import Typst.Types
 import Text.Pandoc.Class.PandocMonad ( PandocMonad, report )
 import Text.Pandoc.Logging (LogMessage(..))
 
-type P m a = ParsecT [Content] () m a
+type P m a = ParsecT [Content] [Text] m a
+-- state tracks a list of labels in the document
 
 pTok :: PandocMonad m => (Content -> Bool) -> P m Content
 pTok f = tokenPrim show showPos match