AST processing changes in v1.4

In Quarto v1.3, we added support for parsing HTML tables as native Pandoc elements, so that sophisticated table layouts are available in more formats. Quarto v1.4 extends this in a few ways.

Finer control over table processing

In v1.3, this HTML processing could be disabled only by specifying an option in the HTML table itself, using quarto-disable-processing="true".

In v1.4, this behavior can be controlled by document- and project-level metadata, using the html-table-processing: none YAML option:

---
html-table-processing: none
---

No HTML tables in this document will be processed.

```{r}
library(huxtable)
# your huxtable tables won't be processed by quarto
```

In addition, you can disable the processing selectively in parts of the document, by surrounding the elements with a fenced div having the attribute {html-table-processing="none"}:

---
html-table-processing: none
---

No HTML tables in this document will be processed.

::: {html-table-processing="none"}

```{r}
library(huxtable)
# your huxtable tables won't be processed by quarto because of
# the surrounding div
```

:::

```{r}
library(gt)
# your gt tables will be processed as in 1.3
```

Include Quarto markdown in LaTeX Raw Blocks

In Quarto v1.3, HTML rawblocks can contain the syntax <span data-qmd="<<markdown-content>>"/> of <span data-qmd-base64="<<base64-encoded-markdown-content>>" to allow libraries that emit raw blocks to benefit from Quarto features such as crossref resolution and shortcodes.

In Quarto v1.4, this feature is also available in LaTeX formats. If the syntax \QuartoMarkdownBase64{<<base64-encoded-markdown-content>>} is detected by Quarto, the contents will be decoded, processed in Quarto (including user filters), and then inserted back into the LaTeX raw block.

This is useful for third-party libraries that seek to emit LaTeX content that nevertheless can have “quarto content”. Note that, unlike the HTML feature, Quarto currently only supports base-64 encoded content in LaTeX blocks.

Note that, unlike the HTML table parsing feature, this LaTeX feature cannot currently be disabled. We expect this to not be necessary because QuartoMarkdownBase64 is unlikely to conflict with existing LaTeX environments.