SimpleTypedDataBinding : Fix half on clang

Author: ericmehl

include/IECorePython/SimpleTypedDataBinding.inl

@@ -101,4 +101,42 @@ struct TypedDataFromType<IECore::BoolData>
 
 };
 
+// Specialize `half` to build on clang. See comment in `construct()` below.
+template<>
+struct TypedDataFromType<IECore::HalfData>
+{
+
+	TypedDataFromType()
+	{
+		boost::python::converter::registry::push_back(
+			&convertible,
+			&construct,
+			boost::python::type_id<IECore::HalfDataPtr>()
+		);
+
+	}
+
+	static void *convertible( PyObject *obj )
+	{
+		boost::python::extract<Imath::half> e( obj );
+		if( e.check() )
+		{
+			return obj;
+		}
+		return nullptr;
+	}
+
+	static void construct( PyObject *obj, boost::python::converter::rvalue_from_python_stage1_data *data )
+	{
+		void *storage = ((boost::python::converter::rvalue_from_python_storage<IECore::HalfDataPtr>*)data)->storage.bytes;
+		// This line is needed to force clang to find the right `half` constructor. Not specializing this, or
+		// creating `HalfData` directly from the return value of `extract<Imath::half>()` results in
+		// `error: no viable conversion from 'boost::python::extract<Imath::half>' to 'Imath_3_1::half'`.
+		Imath::half v = boost::python::extract<Imath::half>( obj );
+		new (storage) IECore::HalfDataPtr( new IECore::HalfData( v ) );
+		data->convertible = storage;
+	}
+
+};
+
 } // namespace IECorePython