anchor.diff:      owner = "ocaml-community";
       repo = "sedlex";
       rev = "v${version}";
  -    sha256 = "18dwl2is5j26z6b1c47b81wvcpxw44fasppdadsrs9vsw63rwcm3";
  +    sha256 = "0iw3phlaqr27jdf857hmj5v5hdl0vngbb2h37p2ll18sw991fxar";
     };
   
     propagatedBuildInputs = [
  -    gen uchar ocaml-migrate-parsetree ppx_tools_versioned
  +    gen uchar ppxlib
     ];
   
     preBuild = ''
  
positive.code: 
    meta = {
      homepage = "https://github.com/ocaml-community/sedlex";
      description = "An OCaml lexer generator for Unicode";
      license = lib.licenses.mit;
      maintainers = [ lib.maintainers.marsam ];
  
negative.code: , buildDunePackage
  , ocaml
  , gen
  , ppxlib
  , uchar
  }:
  
  if lib.versionOlder ocaml.version "4.08"
  then throw "sedlex is not available for OCaml ${ocaml.version}"
  else
  
  