Ask HN: What macro-processing language am I looking for

I have a project that I want to document and one thing I'd like to do is to highlight that the application code is decomposed in a way that maps essentially 1-to-1 to the theoretical framework and the way I'd like to do this is to run `tree` inside of the markup that should be outputted as Markdown in the end.

E.g., passing the following input.some_fileextension file to the processor should evaluate the tree command and put the results there

bla bla bla

$ tree dir

bla bla blah

Is this a task for pandoc? M4? Something else? I want something close to Jupyter notebooks without needing that _entire_ framework at hand.

Or is there some lispy type of thing that I can use?