Best practicaes for binding types like Eigen::Matrix<…>

[svenpilz]

Hi fellow web binders,

I'm looking for best practices to pass types by copy to JS that are mainly (big) arrays, like those used by Eigen. Right now we are returning val objects that we construct by hand, for example converting Eigen::MatrixXd (2d array with dynamic size) from and to:

{
   rows: Number
   cols: Number
   data: Float64Array
}

Would this also be possible with automatic conversions, so we could have function returning/taking Eigen::MatrixXd instead val? Is this possible using something like value_object (with getter return val and setter taking val)? We would like to avoid pure memory views into the heap, as we are using a grow-able heap and also don't want explicit memory management on the JS side.

Are there best practices for this case? For example, pybind maps to automatically to numpy.

Thanks!

Sven