The case is that some Python is used to handle the UI in the Parameters Editor.
This is then used to set some parameters that can be read by related VEX code.
Among the parameters are a couple of multiparm folders.
From the Callback Script in the Edit Parameter Interface this works.
exec(kwargs['node'].parm('./code/code_py').eval());searchGroups()
In this case the problem is that to populate the right multiparm parms from the Python code, the button with the callback script has to send an argument with the index of the multiparm.
exec(kwargs['node'].parm('./code/code_py').eval());searchGroups(index)
Something like this does not work:
exec(kwargs['node'].parm('./code/code_py').eval());name=exec(kwargs['node'].parm(".").parentMultiParm());searchGroups(name)
Get Index of Current MultiParm [www.sidefx.com]is a similar topic, but for an unknown reason it did not seem to work for this situation.
How can you get the index (integer) of a parent multiparm folder when using a button with a callback script?
Edit: Never mind. After a good night's sleep I think a lead was found: "kwargs dict would be useful, but it's only provided with callback scripts afaik." (from the linked reference) Yup, that's it.