I'm trying to use the new arguments block instead of inputparser for all of my Name/Value pairs in MATLAB now, and overall, it's working much better. However, there is one thing I could do with inputparser that I don't seem to be able to do with the argument block, but perhaps there's a way?

I want to write a function that has name/value pairs and an optional input. Using inputparser I was able to check the first element of varargin to see if it was a string (indicating the beginning of a Name/Value pair) or if it was something else (indicating it was my optional input). I'm not sure how to replicate this functionality using the argument block.

To give you an example of what I mean, using a MATLAB built in. I want to do something like how the plot command works, how you can write both

plot(Y, 'LineWidth', 2)

and

plot(X,Y, 'LineWidth', 2)