Convert parsed table caption to HTML to keep formatting (#2583)

* Convert parsed table caption to HTML to keep formatting

* Also apply for PagedHtmlTable

* Correctly handles LaTeX tables

* Add a test for HTML and LaTeX

* Correct regex for testing

* Add changelog

[skip ci]

Author: cderv

news/changelog-1.3.md

@@ -108,6 +108,7 @@
 - the API for shortcode handlers in lua now accepts a fourth parameter `raw_args` which hold the unparsed arguments in a table ([#3833](https://github.com/quarto-dev/quarto-cli/issues/3833)).
 - remove scaffolding div from conditional content in final output ([#3847](https://github.com/quarto-dev/quarto-cli/issues/3847)).
 - ensure proof titles are appended to paragraph nodes ([#3772](https://github.com/quarto-dev/quarto-cli/issues/3772)).
+- Support parsing markdown in table captions in LaTeX and HTML tables ([#2573](https://github.com/quarto-dev/quarto-cli/issues/2573)).
 
 ## Pandoc filter changes
 

src/resources/filters/quarto-pre/table-captions.lua

@@ -167,7 +167,7 @@ function applyTableCaptions(el, tblCaptions, tblLabels)
           -- apply table caption and label
           local beginCaption, captionText, endCaption = raw.text:match(captionPattern)
           if #tblCaptions[idx] > 0 then
-            captionText = pandoc.utils.stringify(tblCaptions[idx])
+            captionText = stringEscape(tblCaptions[idx], "html")
           end
           if #tblLabels[idx] > 0 then
             captionText = captionText .. " {#" .. tblLabels[idx] .. "}"
@@ -182,7 +182,7 @@ function applyTableCaptions(el, tblCaptions, tblLabels)
           end
         elseif hasPagedHtmlTable(raw) then
           if #tblCaptions[idx] > 0 then
-            local captionText = pandoc.utils.stringify(tblCaptions[idx])
+            local captionText = stringEscape(tblCaptions[idx], "html")
             if #tblLabels[idx] > 0 then
               captionText = captionText .. " {#" .. tblLabels[idx] .. "}"
             end
@@ -210,10 +210,8 @@ function applyLatexTableCaption(latex, tblCaption, tblLabel, tablePattern)
   -- apply table caption and label
   local beginCaption, captionText, endCaption = latex:match(latexCaptionPattern)
   if #tblCaption > 0 then
-    captionText = pandoc.utils.stringify(tblCaption)
+    captionText = stringEscape(tblCaption, "latex")
   end
-  -- escape special characters for LaTeX
-  captionText = stringEscape(captionText, "latex")
   if #tblLabel > 0 then
     captionText = captionText .. " {#" .. tblLabel .. "}"
   end

tests/docs/smoke-all/2023/01/16/md-captions.qmd

@@ -0,0 +1,46 @@
+---
+title: markdown in captions
+format:
+  html: default
+  latex: default
+_quarto:
+  tests: 
+    html:
+      ensureHtmlElements:
+        - ["#html caption sup", "#html caption em", "#paged div.table-caption sup", "#paged div.table-caption em", "#md caption sup"]
+    latex:
+      ensureFileRegexMatches:
+        - ["\\\\textsuperscript\\{superscript\\}", "\\\\emph\\{italics\\}"]
+execute: 
+  echo: false
+---
+
+# HTML table {#html}
+```{r}
+#| tbl-cap: Using ^superscript^ or _italics_ in table caption
+#| eval: !expr knitr::is_html_output()
+knitr::kable(head(cars), format = "html")
+```
+
+# Paged table {#paged}
+
+```{r}
+#| tbl-cap: Using ^superscript^ or _italics_ in table caption
+#| eval: !expr knitr::is_html_output()
+rmarkdown::paged_table(head(cars))
+```
+
+# Mardown Table {#md}
+
+```{r}
+#| tbl-cap: Using ^superscript^ in caption
+knitr::kable(head(cars))
+```
+
+# LaTeX table {#latex}
+
+```{r}
+#| tbl-cap: Using _italics_ in caption
+#| eval: !expr knitr::is_latex_output()
+knitr::kable(head(cars), format = "latex")
+```