How to run a driver based ppx with bucklescript

Ppx_driver_with_bucklescript.md

1. Create a dune file:

(library
 (public_name aggregate_ppx_name)
 (kind ppx_rewriter)
 (libraries ppx_deriving_protobuf other_ppx another_ppx))

2. Build:

dune build --profile release

3. Create a script (I called it ppx.exe) in the same directory as bsconfig.json. It'll containt all rewriters listed under libraries above:

./_build/install/default/lib/aggregate_ppx_name/ppx.exe --as-ppx "$@"

4. Add your ./ppx.exe to bsconfig.json

  "ppx-flags": ["./ppx.exe"],

Note: the commands/paths are slightly different if you use esy.