Thanks a lot for not only suggesting an answer, but also explaining how to
debug Lua filters as well as providing the logging script, which helped me
a lot.
My final solution looks like this and I hope it is of help to anyone arrive
at this question via internet search:
function Figure (fig) -- works on Windows
if FORMAT:match 'docx' then
caption = pandoc.utils.stringify(fig.caption.long)
if (string.find(caption, 'Fig') ~= nil) then
cap = fig.caption.long[1].content
fig.caption.long[1].content[1] = pandoc.Strong(cap[1])
num_suffix = string.gsub(cap[3].text,':','.')
fig.caption.long[1].content[3] = pandoc.Strong(num_suffix)
fig_num_string = string.sub(pandoc.utils.stringify(cap[3]), 1, 1)
fig_num = math.floor(tonumber(fig_num_string))
if (fig_num > 6) then
num_str = "S" .. tostring(8-fig_num) .. '.'
fig.caption.long[1].content[3] = pandoc.Strong(num_str)
end
end
end
return fig
end
I'm happy to add when to use short captions:
In case one generates a list of figures in analogy to a table of contents,
it can be very helpful to have short captions whereas longer captions might
be required to explain in more detail what is shown in a figure.
William Lupton schrieb am Dienstag, 13. Juni 2023 um 15:57:05 UTC+2:
> I think that the main thing here is that you need to operate on the Figure
> rather than the Image. Also note that image and figure captions are
> different:
>
> - An image caption is an Inlines list;
> https://pandoc.org/lua-filters.html#type-image
> - A figure caption is a Caption object, which has a long (Blocks list)
> caption with option short (Inlines list) caption;
> https://pandoc.org/lua-filters.html#type-figure
>
> I'm not quite sure when or if you should use the short figure caption, but
> am pretty sure that you do need to set the long figure caption.
>
> Finally, a plug for the https://github.com/pandoc-ext/logging module,
> which can help to shed light on the AST structure. With this document (I
> guessed your input format):
>
> 
>
> ...and with this lua filter (derived from yours):
>
> local logging = require 'logging'
>
> function Figure(fig)
> logging.temp('figure', fig)
> end
>
> function Image(img)
> logging.temp('image', img)
> local caption = pandoc.utils.stringify(img.caption)
>
> if (string.find(caption, 'Fig') ~= nil) then
> img.caption[1] = pandoc.Strong(img.caption[1])
> img.caption[3] = pandoc.Str(string.gsub(img.caption[3].text, ":",
> "."))
> img.caption[3] = pandoc.Strong(img.caption[3])
> local fig_num_string = string.sub(
> pandoc.utils.stringify(img.caption[3]),1,2)
> local fig_num = math.floor(tonumber(fig_num_string))
>
> if (fig_num > 6) then
> img.caption[3] = pandoc.Strong("S" .. tostring(8-fig_num) ..
> '.')
> end
> img.caption.long = pandoc.Strong('A')
> img.caption = pandoc.Strong('A')
> end
> logging.temp('->', img)
> return img
> end
>
> ...you get this output:
>
> % pandoc figure.md -L figure.lua
> (#) image Image {
> attr: Attr {
> attributes: AttributeList {}
> classes: List {}
> identifier: ""
> }
> caption: Inlines[5] {
> [1] Str "Figure"
> [2] Space
> [3] Str "1:"
> [4] Space
> [5] Str "Cat"
> }
> src: "Cat.png"
> title: ""
> }
> (#) -> Image {
> attr: Attr {
> attributes: AttributeList {}
> classes: List {}
> identifier: ""
> }
> caption: Inlines[1] {
> [1] Strong {
> content: Inlines[1] {
> [1] Str "A"
> }
> }
> }
> src: "Cat.png"
> title: ""
> }
> (#) figure Figure {
> attr: Attr {
> attributes: AttributeList {}
> classes: List {}
> identifier: ""
> }
> caption: {
> long: Blocks[1] {
> [1] Plain {
> content: Inlines[5] {
> [1] Str "Figure"
> [2] Space
> [3] Str "1:"
> [4] Space
> [5] Str "Cat"
> }
> }
> }
> }
> content: Blocks[1] {
> [1] Plain {
> content: Inlines[1] {
> [1] Image {
> attr: Attr {
> attributes: AttributeList {}
> classes: List {}
> identifier: ""
> }
> caption: Inlines[1] {
> [1] Strong {
> content: Inlines[1] {
> [1] Str "A"
> }
> }
> }
> src: "Cat.png"
> title: ""
> }
> }
> }
> }
> }
>
>
> Figure 1: Cat
>
>
> On Tue, 13 Jun 2023 at 14:16, Stephan Boltzmann
> wrote:
>
>> Hello everybody out there using Pandoc,
>>
>> The following Lua (used with RMarkdown in RStudio) filter should put "*Figure
>> n.*" in bold at the beginning of every figure caption, but it doesn't
>> change my output:
>>
>> function Image (img)
>> if FORMAT:match 'docx' then
>> caption = pandoc.utils.stringify(img.caption)
>> if (string.find(caption, 'Fig') ~= nil) then
>> img.caption[1] = pandoc.Strong(img.caption[1])
>> img.caption[3] = pandoc.Str(string.gsub(img.caption[3].text, ":",
>> "."))
>> img.caption[3] = pandoc.Strong(img.caption[3])
>> fig_num_string =
>> string.sub(pandoc.utils.stringify(img.caption[3]),1,2)
>> fig_num = math.floor(tonumber(fig_num_string))
>> if (fig_num > 6) then
>> img.caption[3] = pandoc.Strong("S" .. tostring(8-fig_num) .. '.')
>> end
>> img.caption.long = pandoc.Strong('A')
>> img.caption = pandoc.Strong('A')
>> end
>> end
>> print(pandoc.utils.stringify(img.caption.long))
>> return img
>> end
>>
>> By putting print statements, I can partially verify that the filter
>> operates on the correct elements, but it doesn't change the output.
>>
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>>
>> .
>>
>
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