hepmc3: add python support

pkgs/development/libraries/physics/hepmc3/default.nix

@@ -1,4 +1,9 @@
-{ stdenv, fetchurl, cmake, coreutils, root }:
+{ stdenv, fetchurl, cmake, coreutils, python, root }:
+
+let
+  pythonVersion = with stdenv.lib.versions; "${major python.version}${minor python.version}";
+  withPython = python != null;
+in
 
 stdenv.mkDerivation rec {
   pname = "hepmc3";
@@ -10,10 +15,14 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [ cmake ];
-  buildInputs = [ root ];
+  buildInputs = [ root ]
+    ++ stdenv.lib.optional withPython python;
 
   cmakeFlags = [
-    "-DHEPMC3_ENABLE_PYTHON=OFF"
+    "-DHEPMC3_ENABLE_PYTHON=${if withPython then "ON" else "OFF"}"
+  ] ++ stdenv.lib.optionals withPython [
+    "-DHEPMC3_PYTHON_VERSIONS=${if python.isPy3k then "3.X" else "2.X"}"
+    "-DHEPMC3_Python_SITEARCH${pythonVersion}=${placeholder "out"}/${python.sitePackages}"
   ];
 
   postInstall = ''

pkgs/top-level/all-packages.nix

@@ -25153,7 +25153,9 @@ in
 
   hepmc2 = callPackage ../development/libraries/physics/hepmc2 { };
 
-  hepmc3 = callPackage ../development/libraries/physics/hepmc3 { };
+  hepmc3 = callPackage ../development/libraries/physics/hepmc3 {
+    python = null;
+  };
 
   herwig = callPackage ../development/libraries/physics/herwig { };
 

pkgs/top-level/python-packages.nix

@@ -2256,6 +2256,10 @@ in {
 
   jsonrpc-websocket = callPackage ../development/python-modules/jsonrpc-websocket { };
 
+  hepmc3 = toPythonModule (pkgs.hepmc3.override {
+    inherit python;
+  });
+
   onkyo-eiscp = callPackage ../development/python-modules/onkyo-eiscp { };
 
   tablib = callPackage ../development/python-modules/tablib { };