Let's keep our fingers crossed that it will make it.
Not sure about this specific notation proposal, because if I understand your proposal correctly I fear it might render existing scripts incompatible.
P.HERE x currently writes x to the current index of working pattern. It should do so in TTv2, otherwise existing scripts would need to be either manually (error prone, plus I am lazy) or automatically converted (which would increase tehn's workload).
In my understanding of your notation proposal,
P.HERE x would be replaced with
P.HERE [0..3] x, so it required 2 numbers (first pattern, then value).
At the same time, the command
P.HERE would still be required to work, this command currently reads the value at the current index of the working pattern. In my understanding of your proposal, it would have to become
This is where things would get sort of slippy, because the new
P.HERE [0..3] (read value at current index of pattern [0..3])
would become indistinguishable from the existing
P.HERE x (write x to current index of working pattern).
So a replacement for the functionality of
P.HERE x would be needed.
This can quickly become quite confusing, that's why I'd rather see the pattern definition as part of the command itself, rather then become a part of the argument. Then we can continue to use the existing syntax for the existing functionality.
But hey, that's just me trying to think aloud. I have no clue about programming (that's why I like TT ), so chances are I am talking complete nonsense here.