Extra #block[ ] when translating column-block to typst

[ihrke]

Bug description

When creating a block with multiple columns using :::{layout-ncol=2}, for example, the Typst output uses the Typst function grid() as expected. However, just before the grid(), the conversion inserts an empty block and that messes up the spacing in the output. See MWE below.

Steps to reproduce

Minimal file that produces the bug:

---
format: 
    typst: 
        keep-typ: true
---

:::{layout-ncol=2}

Test 1

Test 2

:::

translating this file to Typst using quarto render test.md produces this Typst file:

// ... default Typst template stuff

#block[
]
#grid(
columns: (50.0%, 50.0%), gutter: 1em, rows: 1,
  rect(stroke: none, width: 100%)[
Test 1

],
  rect(stroke: none, width: 100%)[
Test 2

],
)

The first block[ ] is erroneous and should not be there (its presence introduces spacing there which messes up the rest of the page).

Expected behavior

The Typst file should look like this:

// ... default Typst template stuff

#grid(
columns: (50.0%, 50.0%), gutter: 1em, rows: 1,
  rect(stroke: none, width: 100%)[
Test 1

],
  rect(stroke: none, width: 100%)[
Test 2

],
)

Actual behavior

As described above, the Typst file looks like

// ... default Typst template stuff

#block[
]
#grid(
columns: (50.0%, 50.0%), gutter: 1em, rows: 1,
  rect(stroke: none, width: 100%)[
Test 1

],
  rect(stroke: none, width: 100%)[
Test 2

],
)

Your environment

• IDE: VSCode (irrelevant)
• Linux (Ubuntu 24) (irrelevant)
• Typst: 0.12.0

Quarto check output

Quarto 1.7.1
[✓] Checking environment information...
      Quarto cache location: /home/mmi041/.cache/quarto
[✓] Checking versions of quarto binary dependencies...
      Pandoc version 3.4.0: OK
      Dart Sass version 1.70.0: OK
      Deno version 1.46.3: OK
      Typst version 0.12.0: OK
[✓] Checking versions of quarto dependencies......OK
[✓] Checking Quarto installation......OK
      Version: 1.7.1
      Path: /opt/quarto/bin

[✓] Checking tools....................OK
      TinyTeX: (not installed)
      Chromium: (not installed)

[✓] Checking LaTeX....................OK
      Using: Installation From Path
      Path: /usr/bin
      Version: 2024

[✓] Checking basic markdown render....OK

[✓] Checking Python 3 installation....OK
      Version: 3.12.2 (Conda)
      Path: /home/mmi041/miniconda3/bin/python
      Jupyter: (None)

      Jupyter is not available in this Python installation.
      Install with conda install jupyter

[✓] Checking R installation...........OK
      Version: 4.4.1
      Path: /usr/lib/R
      LibPaths:
        - /home/mmi041/R/x86_64-pc-linux-gnu-library/4.4
        - /usr/local/lib/R/site-library
        - /usr/lib/R/site-library
        - /usr/lib/R/library
      knitr: 1.48
      rmarkdown: 2.28

[✓] Checking Knitr engine render......OK

[mcanouil]

Thanks for the report.
I can reproduce.

I think the issue lies in how the Panel Layout is built: https://github.com/quarto-dev/quarto-cli/blob/main/src/resources/filters/customnodes/panellayout.lua

The extra block is not there if the layout is a cross-ref float for instance.

[cderv]

If we look at trace for our lua chain we can see an empty Div at the end which is not removed

blocks:
  - t: "Div"
    attr: "('', [], [])"
    content: []
  - t: "RawBlock"
    format: "typst"
    text: "#grid("
  - t: "RawBlock"
    format: "typst"
    text: "columns: (1fr, 1fr), gutter: 1em, rows: 1,"
  - t: "RawBlock"
    format: "typst"
    text: "  rect(stroke: none, width: 100%)["
  - t: "Para"
    content: "Test 1"
  - t: "RawBlock"
    format: "typst"
    text: "],"
  - t: "RawBlock"
    format: "typst"
    text: "  rect(stroke: none, width: 100%)["
  - t: "Para"
    content: "Test 2"
  - t: "RawBlock"
    format: "typst"
    text: "],"
  - t: "RawBlock"
    format: "typst"
    text: ")\n"

This block is the result for panel layout process indeed

This

blocks:
  - t: "Div"
    attr: "('', [], ['layout-ncol,2'])"
    content:
      - t: "Para"
        content: "Test 1"
      - t: "Para"
        content: "Test 2"

is transformed to this custom ast node

blocks:
  - customAST: true
    attributes:
      layout-ncol: "2"
    classes: []
    identifier: ""
    is_float_reftarget: false
    layout:
      - []
    t: "PanelLayout"
    scaffold:
      - t: "Div"
        attr: "('', [], ['__quarto_custom_scaffold,true'])"
        content:
          - t: "Div"
            attr: "('', [], [])"
            content: []
      - t: "Div"
        attr: "('', [], ['__quarto_custom_scaffold,true'])"
        content:
          - t: "Div"
            attr: "('', [], [])"
            content:
              - t: "Div"
                attr: "('', [], [])"
                content:
                  - t: "Div"
                    attr: "('', [], ['width,1fr', 'layout-align,left'])"
                    content:
                      - t: "Para"
                        content: "Test 1"
                  - t: "Div"
                    attr: "('', [], ['width,1fr', 'layout-align,left'])"
                    content:
                      - t: "Para"
                        content: "Test 2"

And see this part

      - t: "Div"
        attr: "('', [], ['__quarto_custom_scaffold,true'])"
        content:
          - t: "Div"
            attr: "('', [], [])"
            content: []

which leads to empty div, not removed.

This should not be produced at all in layout IMO. However, I thought empty div are also supposed to be removed 🤔

but it seems we do it only for LaTex: No class, no id, not attributes on a div means we do like a scaffolded div and we don't return the Div.

quarto-cli/src/resources/filters/quarto-finalize/finalize-combined-1.lua

Lines 34 to 39 in 1dc41fa

	Div = function(el)
	if (quarto.doc.isFormat("latex") and #el.classes == 0 and #el.attributes == 0 and el.identifier == "") or -- coalesce_raw
	el.classes:includes("quarto-scaffold") then -- descaffold
	return el.content
	end
	end,

So there is two ways to deal with that:

• Specifically in Layout Panel to make sure we don't produce empty div
• More generally in our finalizer to make sure we do remove empty div in LaTeX to

I think the latter should done s we don't want empty block generally in typst

[cderv]

Specifically in Layout Panel to make sure we don't produce empty div

I think the problem is that when preamble is empty list

quarto-cli/src/resources/filters/layout/layout.lua

Lines 30 to 36 in 1dc41fa

	local preamble, cells = partition_cells(div)
	local layout = layout_cells(div, cells)
	return quarto.PanelLayout({
	attr = div.attr,
	preamble = preamble,
	layout = layout,
	})

as default are pandoc.List() for both preamble and cell

quarto-cli/src/resources/filters/layout/layout.lua

Lines 74 to 76 in 1dc41fa

	function partition_cells(float)
	local preamble = pandoc.List()
	local cells = pandoc.List()

we do construct a div with it

quarto-cli/src/resources/filters/customnodes/panellayout.lua

Line 79 in 1dc41fa

tbl.preamble = pandoc.Div(tbl.preamble)

but we only do nothing when it is nil not pandoc.Div({})

quarto-cli/src/resources/filters/quarto-pre/panel-layout.lua

Lines 39 to 55 in 1dc41fa

	function panel_insert_preamble(result, preamble)
	if preamble == nil then
	return
	end
	local pt = pandoc.utils.type(preamble)
	if preamble.content and #preamble.content > 0 then
	result:extend(preamble.content)
	elseif pt == "Inline" or pt == "Block" then
	result:insert(preamble)
	elseif pt == "Blocks" then
	result:extend(preamble)
	else
	fail("Don't know what to do with preamble of type " .. pt)
	return nil
	end
	end