Backward compatibility

[tjibbed]

As part of a dashboard development I noticed the following:

RDS files created using older versions of the package don't allow for the node and ring colouring in the circular network plot, even when using the newer version of the package. This because the plotting function is stored in the HospiNet object, and the older plotting function doesn't recognise the extra arguments.

To solve this, I propose creating a version of the $new() function that just takes the entire object, copies the network information into the current HospiNet object, that does contain the current plotting function.

As an additions, I'd like to propose adding an attribute to the object that contains the version number, so any application using the package can check if the input object was created using the most recent version.

[tjibbed]

Note that my current workaround suffers from a bug reported in issue #28

[PascalCrepey]

I see at least three options to solve this issue:
1- the one you suggest
2- moving the plotting functions (and maybe other functions that could be updated) outside of the R6 object so that they get updated when the package is updated, and you don't need to update the object if it has been created with a previous version (as long as it's still mostly compatible regarding the data presentation)
3- replace R6 with S7 (the next object-oriented system developed by the R consortium) where methods are outside the object anyway.

Going toward option 2 would prepare for option 3 without much work and with maintaining backward compatibility, so that would be my preference...