Add suffix to multiple HTML5 footnote section ids

The first (and often only) `<aside id=footnotes>` block remains unchanged, however any additional blocks from `--reference-location` are distinguished as `#footnotes-2`, `#footnotes-3`, and so on. No other existing writer seems to implement per-section IDs, including HTML4.
jgm · Apr 10, 2023 · ad75fa8 · ad75fa8
1 parent 9bcf1ff
commit ad75fa8
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Showing 3 changed files with 808 additions and 4 deletions.
diff --git a/src/Text/Pandoc/Writers/HTML.hs b/src/Text/Pandoc/Writers/HTML.hs
@@ -87,6 +87,7 @@ import Data.String (fromString)
 data WriterState = WriterState
     { stNotes        :: [Html]  -- ^ List of notes
     , stEmittedNotes :: Int     -- ^ How many notes we've already pushed out to the HTML
+    , stEmittedNoteBlocks :: Int  -- ^ How many <div class=footnote> blocks we've already pushed out
     , stMath         :: Bool    -- ^ Math is used in document
     , stQuotes       :: Bool    -- ^ <q> tag is used
     , stHighlighting :: Bool    -- ^ Syntax highlighting is used
@@ -102,7 +103,11 @@ data WriterState = WriterState
     }
 
 defaultWriterState :: WriterState
-defaultWriterState = WriterState {stNotes= [], stEmittedNotes = 0, stMath = False, stQuotes = False,
+defaultWriterState = WriterState {stNotes= [],
+                                  stEmittedNotes = 0,
+                                  stEmittedNoteBlocks = 0,
+                                  stMath = False,
+                                  stQuotes = False,
                                   stHighlighting = False,
                                   stHtml5 = False,
                                   stEPUBVersion = Nothing,
@@ -531,6 +536,16 @@ footnoteSection refLocation startCounter notes = do
   let hrtag = if refLocation /= EndOfBlock
                  then (if html5 then H5.hr else H.hr) <> nl
                  else mempty
+  idName <- do
+    blockCount <- gets stEmittedNoteBlocks
+    modify $ \st -> st{ stEmittedNoteBlocks = blockCount + 1 }
+    return $
+      -- Keep the first note section's id undecorated to maintain a target for
+      -- old links which don't expect numbered sections, or for when the notes
+      -- are rendered all together at the end of the document.
+      if blockCount <= 0
+        then "footnotes"
+        else "footnotes-" <> fromString (show $ blockCount + 1)
   let additionalClassName = case refLocation of
         EndOfBlock -> "footnotes-end-of-block"
         EndOfDocument -> "footnotes-end-of-document"
@@ -540,17 +555,17 @@ footnoteSection refLocation startCounter notes = do
   let container x
         | html5
         , epubVersion == Just EPUB3
-                = H5.section ! A.id "footnotes"
+                = H5.section ! A.id idName
                              ! A.class_ className
                              ! customAttribute "epub:type" "footnotes" $ x
         | html5
         , refLocation == EndOfDocument
         , slideVariant == RevealJsSlides -- need a section for a new slide:
-                = H5.section ! A5.id "footnotes"
+                = H5.section ! A5.id idName
                              ! A5.class_ className
                              ! A5.role "doc-endnotes"
                              $ x
-        | html5 = H5.aside   ! A5.id "footnotes"
+        | html5 = H5.aside   ! A5.id idName
                              ! A5.class_ className
                              ! A5.role "doc-endnotes"
                              $ x

diff --git a/test/Tests/Old.hs b/test/Tests/Old.hs
@@ -67,6 +67,9 @@ tests pandocPath =
       [ extWriterTests' "html4"
       , extWriterTests' "html5"
       , lhsWriterTests' "html"
+      , [ test' "block-footnotes" ["-r", "native", "-w", "html5", "-s", "--reference-location=block"]
+          "writer.native" "writer_blocknotes.html5"
+        ]
       ]
     , test' "reader" ["-r", "html", "-w", "native", "-s"]
       "html-reader.html" "html-reader.native"