Cache the value returned by the property

[joseangelmt]

I'm embedding Python in an application. The principal mission of the implementation is to expose to the Python world already instantiated C++ objects via py::cast(), so my py::class_<..> classes don't have any constructor. Python users can't instantiate these objects.

One of the exposed C++ objects has a std::map<> field with data non compatible with Python. This field is exposed to Python via def_property_readonly(...) that implements a lambda that constructs and returns a py::dict.

Creating this py::dict can be a bottleneck so I wish to cache it in memory, so it's created only the first time.

Is it possible to do it?

Thanks in advance.