Feature request: une channel number as a variable in Formula

[nesdnuma]

Hello,

I really love Formula. It is a great problem solver.

Its scope could be even broader if channel number within a polyphonic signal could be used as a variable. So one could change the results of the operation according to the channel or apply some operations differently channel per channel (like > or <...). One could even imagine some ways to transform a monophonic signal into a polyphonic.