Announcing pandoc-select-code: a pandoc filter to extract only the code blocks. You might use this, for example, to extract sample code from a tutorial. This package has been available from my repo for a while, but I have now uploaded it to Hackage, and also made it available as a Nix flake.
I originally developed this filter because I wanted something like literate Haskell, but using Markdown. I wanted to be able to write a Markdown file with Haskell code blocks, and then be able to compile and execute it, or use Pandoc to produce a PDF. Cabal doesn't support that, so one workaround is to pre-process the file using Pandoc with this filter and the --write=plain option to produce a source file that can be compiled.
I also use this when I'm updating a tutorial I wrote some time ago; I'll extract the code examples and verify that they still work with the latest software.
Hackage: https://hackage.haskell.org/package/pandoc-select-code
Repo: https://github.com/mhwombat/pandoc-select-code