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Typst property output

Pandoc Typst property output

In addition to the output of structural properties built into Pandoc’s Typst Writer, the Writer can also output non-structural Typst properties. This is enabled by setting attributes with keys of the form typst:prop or typst:text:prop on supported elements.

Typst properties

Typst allows specification of visual and layout properties as parameters to elements

#block(fill=orange)[Hello]

and set-rules

#set text(fill=blue); Hello

The parameter values are Typst code that can use any features of the Typst language.

Pandoc Typst property output

For the set of supported Pandoc elements, the Pandoc Typst Writer will output attributes as parameters to corresponding Typst elements or set-text rules.

The Typst Writer looks for attributes with keys of the form typst:prop or typst:text:prop and assumes the values are raw Typst code.

prop is the name of the property to set.

For example, pandoc -f html -t typst with HTML input

<div typst:inset="10pt">foo</div>

produces Typst output

#block(inset: 10pt)[
foo
]

and with HTML input

<div typst:text:fill="purple">foo</div>

it produces Typst output

#block[
#set text(fill: purple); foo
]

The Typst Writer does not check the validity of prop or the value. Since Typst is a statically typed language, improper property names or values usually result in compilation failure.

Supported elements

The following Pandoc AST elements are currently supported. More may be supported in the future.

  • Span

    typst:text:prop

    The content is wrapped in a Typst text element with the specified properties set.

  • Div

    typst:prop

    The prop is output as a parameter to the Typst block element.

    typst:text:prop

    The prop is output as a parameter to a set-text rule at the start of the block content.

  • Table

    typst:prop

    The prop is output as a parameter to the Typst table element.

    typst:text:prop

    The table is wrapped in a Typst text element with prop as one of its parameters.

  • Table Cell

    typst:prop

    The prop is output as a parameter to the Typst table cell element.

    typst:text:prop

    The prop is output as a parameter to a set-text rule at the start of the cell content.

Lua filter example

Here is a minimal example of a Lua filter which translates the CSS color property on a span element to the equivalent fill parameter on a Typst text element.

function styleToTable(style)
  if not style then return nil end
  local ret = {}
  for clause in style:gmatch('([^;]+)') do
    k,v = clause:match("([%w-]+)%s*:%s*(.*)$")
    ret[k] = v
  end
  return ret
end

function Span(span)
  local style = styleToTable(span.attributes['style'])
  if not style then return end
  if style['color'] then
    span.attributes['typst:text:fill'] = style['color']
  end
  return span
end

Given the HTML input

<p>Here is some <span style="color:orange">orange text</span>.</p>

the command

pandoc -f html -t typst --lua-filter ./typst-property-example.lua

will produce the Typst output

Here is some #text(fill: orange)[orange text].

Of course, this simple filter will only work for Typst’s predefined colors. A more complete filter would need to translate the value as well.