A filter to replace some contents with metadata

[massifrg]

Hello, does anybody know of a filter or a feature of pandoc that lets you replace some placeholder elements in a document with the value of a metadata field?

Think of a customized letter (template-letter.md), that starts with:

Dear [recipient]{.replace-with-meta key="recipient"},
...

You could get the customized docx version with a command like this:

pandoc -f markdown -t docx --metadata recipient="Peter" -L replace-meta.lua -o letter.docx template-letter.md

where replace-meta.lua is that kind of filter.

I know it is possible with templates; what about (template-)documents?

Templates are specific to a format, while documents can be converted in many output formats.

[jgm]

You mean something like this example from the documentation?
https://pandoc.org/lua-filters.html#replacing-placeholders-with-their-metadata-value

[massifrg]

Oops, I read those docs a lot of times... 😳

Thank you!
That is much simpler than what I was thinking of, because I tend to reason more in terms of AST nodes than of markdown syntax, though the example is not markdown-specific.