fix: ensure back-labels are emitted only once

Author: mcanouil

src/format/typst/format-typst.ts

@@ -210,7 +210,7 @@ function skylightingPostProcessor(brandBgColor?: string) {
     /\/\/ quarto-code-annotations: ([\w-]*) (\([^)]*\))\n(\s*(?:#block\[\s*)*(?:#quarto-code-filename\([^\n]*\)\[\s*)?)#Skylighting\(/g;
 
   return async (output: string) => {
-    let content = Deno.readTextFileSync(output);
+    let content = Deno.readTextFileSync(output).replace(/\r\n/g, "\n");
     let changed = false;
 
     const match = skylightingFnRe.exec(content);
@@ -243,14 +243,27 @@ function skylightingPostProcessor(brandBgColor?: string) {
         "lnum = lnum + 1\n     if number {\n",
       );
 
+      // Initialise a dictionary to track which annotation numbers have
+      // already emitted a back-label (avoids duplicate labels when one
+      // annotation spans multiple lines).
+      fn = fn.replace(
+        /let lnum = start - 1\n/,
+        "let lnum = start - 1\n     let seen-annotes = (:)\n",
+      );
+
       // Add annotation rendering per line (derive circle colour from bgcolor)
       fn = fn.replace(
         "blocks = blocks + ln + EndLine()",
         `let annote-num = annotations.at(str(lnum), default: none)
      if annote-num != none {
        if cell-id != "" {
          let lbl = cell-id + "-annote-" + str(annote-num)
-         blocks = blocks + box(width: 100%)[#ln #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: quarto-annote-color(bgcolor))] #label(lbl + "-back")] + EndLine()
+         if str(annote-num) not in seen-annotes {
+           seen-annotes.insert(str(annote-num), true)
+           blocks = blocks + box(width: 100%)[#ln #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: quarto-annote-color(bgcolor))] #label(lbl + "-back")] + EndLine()
+         } else {
+           blocks = blocks + box(width: 100%)[#ln #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: quarto-annote-color(bgcolor))]] + EndLine()
+         }
        } else {
          blocks = blocks + box(width: 100%)[#ln #h(1fr) #quarto-circled-number(annote-num, color: quarto-annote-color(bgcolor))] + EndLine()
        }

src/resources/filters/quarto-pre/code-annotation.lua

@@ -126,18 +126,16 @@ local function wrapTypstAnnotatedCode(codeBlock, annotations, cellId)
     adjustedAnnotations[annoteId] = adjusted
   end
   local dict = typstAnnotationsDict(adjustedAnnotations)
-  local cellIdParam = ""
-  if cellId and cellId ~= "" then
-    cellIdParam = ", cell-id: \"" .. cellId .. "\""
-  end
   local lang = codeBlock.attr.classes[1] or ""
   local code = codeBlock.text
   local maxBackticks = 2
   for seq in code:gmatch("`+") do
     maxBackticks = math.max(maxBackticks, #seq)
   end
   local fence = string.rep("`", maxBackticks + 1)
-  local raw = "#quarto-code-annotation(" .. dict .. cellIdParam .. ")[" .. fence .. lang .. "\n" .. code .. "\n" .. fence .. "]"
+  local raw = "#quarto-code-annotation(" .. dict
+    .. (cellId and cellId ~= "" and (", cell-id: \"" .. cellId .. "\"") or "")
+    .. ")[" .. fence .. lang .. "\n" .. code .. "\n" .. fence .. "]"
   return pandoc.RawBlock("typst", raw)
 end
 
@@ -568,14 +566,12 @@ function code_annotations()
                 end
               end
 
-              local useSkylighting = param(constants.kSyntaxHighlighting, true)
-
               if pendingCodeCell ~= nil then
                 local resolvedCell = _quarto.ast.walk(pendingCodeCell, {
                   CodeBlock = function(el)
                     if el.attr.classes:find('cell-code') or
                        el.attr.classes:find(constants.kDataCodeAnnonationClz) then
-                      if useSkylighting then
+                      if param(constants.kSyntaxHighlighting, true) then
                         return nil
                       else
                         return wrapTypstAnnotatedCode(el, pendingAnnotations, pendingCellId)
@@ -587,12 +583,12 @@ function code_annotations()
                 local dlDiv = pandoc.Div(annotationBlocks, pandoc.Attr("", {constants.kCellAnnotationClass}))
                 if is_custom_node(resolvedCell) then
                   local custom = _quarto.ast.resolve_custom_data(resolvedCell) or pandoc.Div({})
-                  if useSkylighting then
+                  if param(constants.kSyntaxHighlighting, true) then
                     custom.content:insert(1, typstAnnotationMarker(pendingAnnotations, pendingCellId))
                   end
                   custom.content:insert(dlDiv)
                 else
-                  if useSkylighting then
+                  if param(constants.kSyntaxHighlighting, true) then
                     resolvedCell.content:insert(1, typstAnnotationMarker(pendingAnnotations, pendingCellId))
                   end
                   resolvedCell.content:insert(dlDiv)

src/resources/formats/typst/pandoc/quarto/definitions.typ

@@ -60,13 +60,28 @@
 }
 
 #let quarto-code-annotation(annotations, cell-id: "", color: luma(60), body) = {
+  // Build a set of first-line positions per annotation number so that
+  // back-labels are only emitted once (avoiding duplicate labels when
+  // one annotation spans multiple lines).
+  let first-lines = (:)
+  for (line, num) in annotations {
+    let key = str(num)
+    if key not in first-lines or int(line) < int(first-lines.at(key)) {
+      first-lines.insert(key, line)
+    }
+  }
   show raw.where(block: true): it => it
   show raw.line: it => {
     let annote-num = annotations.at(str(it.number), default: none)
     if annote-num != none {
       if cell-id != "" {
         let lbl = cell-id + "-annote-" + str(annote-num)
-        box(width: 100%)[#it #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: color)] #label(lbl + "-back")]
+        let is-first = first-lines.at(str(annote-num), default: none) == str(it.number)
+        if is-first {
+          box(width: 100%)[#it #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: color)] #label(lbl + "-back")]
+        } else {
+          box(width: 100%)[#it #h(1fr) #link(label(lbl))[#quarto-circled-number(annote-num, color: color)]]
+        }
       } else {
         box(width: 100%)[#it #h(1fr) #quarto-circled-number(annote-num, color: color)]
       }