core/pkgs/build-support/ocaml/dune.nix

{
  lib,
  stdenv,
  ocaml,
  findlib,
  dune_1,
  dune_2,
  dune_3,
}:

{
  pname,
  version,
  nativeBuildInputs ? [ ],
  enableParallelBuilding ? true,
  ...
}@args:

let
  Dune =
    let
      dune-version = args.duneVersion or "3";
    in
    {
      "1" = dune_1;
      "2" = dune_2;
      "3" = dune_3;
    }
    ."${dune-version}";
in

if
  (args ? minimumOCamlVersion && lib.versionOlder ocaml.version args.minimumOCamlVersion)
  || (args ? minimalOCamlVersion && lib.versionOlder ocaml.version args.minimalOCamlVersion)
then
  throw "${pname}-${version} is not available for OCaml ${ocaml.version}"
else

  stdenv.mkDerivation (
    {

      inherit enableParallelBuilding;
      dontAddStaticConfigureFlags = true;
      configurePlatforms = [ ];

      buildPhase = ''
        runHook preBuild
        dune build -p ${pname} ''${enableParallelBuilding:+-j $NIX_BUILD_CORES}
        runHook postBuild
      '';
      checkPhase = ''
        runHook preCheck
        dune runtest -p ${pname} ''${enableParallelBuilding:+-j $NIX_BUILD_CORES}
        runHook postCheck
      '';
      installPhase = ''
        runHook preInstall
        dune install --prefix $out --libdir $OCAMLFIND_DESTDIR ${pname} \
         ${
           if lib.versionAtLeast Dune.version "2.9" then
             "--docdir $out/share/doc --mandir $out/share/man"
           else
             ""
         }
        runHook postInstall
      '';

      strictDeps = true;

    }
    // (builtins.removeAttrs args [
      "minimalOCamlVersion"
      "duneVersion"
    ])
    // {

      name = "ocaml${ocaml.version}-${pname}-${version}";

      nativeBuildInputs = [
        ocaml
        Dune
        findlib
      ] ++ nativeBuildInputs;

      meta = (args.meta or { }) // {
        platforms = args.meta.platforms or ocaml.meta.platforms;
      };

    }
  )