I hope someone can help with this. I think I am just missing a simple trick

I have created a Application_SheetBeforeDoubleClick event in which I would like my code to look at the formula in the cell being double-clicked, then extract the parameters being passed to the function. For example:

Function in cell:- =Left(B1,4

I would like my code to return the parameters 'B1', and '4'. So far I am stripping off the unnecessary text to leave 'B1,4', and then using the SPLIT function to separate the parameters. This works fine for simple functions but for functions where the parameters may have commas in them themselves, this isn't going to work

If anyone can help, I would me most grateful