LaTeX reader: Handle `\label` and `\ref` for footnotes.

Closes #7930.

3 files changed, 117 insertions, 1 deletions

diff --git a/src/Text/Pandoc/Readers/LaTeX.hs b/src/Text/Pandoc/Readers/LaTeX.hs
index e2b283cf2..32fae9021 100644
--- a/src/Text/Pandoc/Readers/LaTeX.hs
+++ b/src/Text/Pandoc/Readers/LaTeX.hs
@@ -383,7 +383,7 @@ inlineCommands = M.unions
     , ("MakeTextLowercase", makeLowercase <$> tok)
     , ("lowercase", makeLowercase <$> tok)
     , ("thanks", skipopts >> note <$> grouped block)
-    , ("footnote", skipopts >> note <$> grouped block)
+    , ("footnote", skipopts >> footnote)
     , ("passthrough", tok) -- \passthrough macro used by latex writer
                            -- for listings
     , ("includegraphics", do options <- option [] keyvals
@@ -431,6 +431,22 @@ today =
   text . T.pack . showGregorian . localDay . zonedTimeToLocalTime
     <$> getZonedTime
 
+footnote :: PandocMonad m => LP m Inlines
+footnote = do
+  updateState $ \st -> st{ sLastNoteNum = sLastNoteNum st + 1 }
+  contents <- grouped block >>= walkM resolveNoteLabel
+  return $ note contents
+
+resolveNoteLabel :: PandocMonad m => Inline -> LP m Inline
+resolveNoteLabel (Span (_,cls,kvs) _)
+  | Just lab <- lookup "label" kvs = do
+      updateState $ \st -> st{
+        sLabels = M.insert lab (toList . text . tshow $ sLastNoteNum st)
+                      $ sLabels st }
+      return $ Span (lab,cls,kvs) []
+resolveNoteLabel il = return il
+
+
 lettrine :: PandocMonad m => LP m Inlines
 lettrine = do
   optional rawopt
diff --git a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
index 4807c817f..431da1a1f 100644
--- a/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
+++ b/src/Text/Pandoc/Readers/LaTeX/Parsing.hs
@@ -162,6 +162,7 @@ data LaTeXState = LaTeXState{ sOptions       :: ReaderOptions
                             , sLastHeaderNum :: DottedNum
                             , sLastFigureNum :: DottedNum
                             , sLastTableNum  :: DottedNum
+                            , sLastNoteNum   :: Int
                             , sTheoremMap    :: M.Map Text TheoremSpec
                             , sLastTheoremStyle :: TheoremStyle
                             , sLastLabel     :: Maybe Text
@@ -189,6 +190,7 @@ defaultLaTeXState = LaTeXState{ sOptions       = def
                               , sLastHeaderNum = DottedNum []
                               , sLastFigureNum = DottedNum []
                               , sLastTableNum  = DottedNum []
+                              , sLastNoteNum   = 0
                               , sTheoremMap    = M.empty
                               , sLastTheoremStyle = PlainStyle
                               , sLastLabel     = Nothing
diff --git a/test/command/7930.md b/test/command/7930.md
new file mode 100644
index 000000000..5e3625419
--- /dev/null
+++ b/test/command/7930.md
@@ -0,0 +1,98 @@
+```
+% pandoc -f latex -t native
+We discuss foobar in notes \ref{note:X} and \ref{note:Y}.
+
+Foo.\footnote{\label{note:X}A note. See also note~\ref{note:Y}.}
+
+Bar.\footnote{\label{note:Y}Another note. See also
+note~\ref{note:X}}
+^D
+[ Para
+    [ Str "We"
+    , Space
+    , Str "discuss"
+    , Space
+    , Str "foobar"
+    , Space
+    , Str "in"
+    , Space
+    , Str "notes"
+    , Space
+    , Link
+        ( ""
+        , []
+        , [ ( "reference-type" , "ref" )
+          , ( "reference" , "note:X" )
+          ]
+        )
+        [ Str "1" ]
+        ( "#note:X" , "" )
+    , Space
+    , Str "and"
+    , Space
+    , Link
+        ( ""
+        , []
+        , [ ( "reference-type" , "ref" )
+          , ( "reference" , "note:Y" )
+          ]
+        )
+        [ Str "2" ]
+        ( "#note:Y" , "" )
+    , Str "."
+    ]
+, Para
+    [ Str "Foo."
+    , Note
+        [ Para
+            [ Span ( "note:X" , [] , [ ( "label" , "note:X" ) ] ) []
+            , Str "A"
+            , Space
+            , Str "note."
+            , Space
+            , Str "See"
+            , Space
+            , Str "also"
+            , Space
+            , Str "note\160"
+            , Link
+                ( ""
+                , []
+                , [ ( "reference-type" , "ref" )
+                  , ( "reference" , "note:Y" )
+                  ]
+                )
+                [ Str "2" ]
+                ( "#note:Y" , "" )
+            , Str "."
+            ]
+        ]
+    ]
+, Para
+    [ Str "Bar."
+    , Note
+        [ Para
+            [ Span ( "note:Y" , [] , [ ( "label" , "note:Y" ) ] ) []
+            , Str "Another"
+            , Space
+            , Str "note."
+            , Space
+            , Str "See"
+            , Space
+            , Str "also"
+            , SoftBreak
+            , Str "note\160"
+            , Link
+                ( ""
+                , []
+                , [ ( "reference-type" , "ref" )
+                  , ( "reference" , "note:X" )
+                  ]
+                )
+                [ Str "1" ]
+                ( "#note:X" , "" )
+            ]
+        ]
+    ]
+]
+```