{ lib, stdenv, fetchFromGitHub, ocaml, findlib, perl, makeWrapper
, rresult, bos, re, camlp-streams
, legacy ? false
}:

if lib.versionOlder ocaml.version "4.02"
then throw "camlp5 is not available for OCaml ${ocaml.version}"
else

let params =
  if lib.versionAtLeast ocaml.version "4.12" && !legacy
  then rec {
    version = "8.02.01";

    src = fetchFromGitHub {
      owner = "camlp5";
      repo = "camlp5";
      rev = version;
      hash = "sha256-qSA2559vqWLU+0ns7LPUGI2K5f8sfu+QQ0sCH8sR6To=";
    };

    nativeBuildInputs = [ makeWrapper ocaml findlib perl ];
    buildInputs = [ bos re rresult ];
    propagatedBuildInputs = [ camlp-streams ];

  } else rec {
    version = "7.14";
    src = fetchFromGitHub {
      owner = "camlp5";
      repo = "camlp5";
      rev = "rel${builtins.replaceStrings [ "." ] [ "" ] version}";
      sha256 = "1dd68bisbpqn5lq2pslm582hxglcxnbkgfkwhdz67z4w9d5nvr7w";
    };
    nativeBuildInputs = [ ocaml perl ];
  }
; in

stdenv.mkDerivation (params // {

  pname = "ocaml${ocaml.version}-camlp5";

  strictDeps = true;

  prefixKey = "-prefix ";

  preConfigure = ''
    configureFlagsArray=(--strict --libdir $out/lib/ocaml/${ocaml.version}/site-lib)
    patchShebangs ./config/find_stuffversion.pl etc/META.pl
  '';

  buildFlags = [ "world.opt" ];

  dontStrip = true;

  meta = with lib; {
    description = "Preprocessor-pretty-printer for OCaml";
    longDescription = ''
      Camlp5 is a preprocessor and pretty-printer for OCaml programs.
      It also provides parsing and printing tools.
    '';
    homepage = "https://camlp5.github.io/";
    license = licenses.bsd3;
    platforms = ocaml.meta.platforms or [];
    maintainers = with maintainers; [
      maggesi vbgl
    ];
  };
})