Yep, that shouldn't be too hard. WikiTi will obviously help if you haven't checked it. What I would do is make a null parser hook (i.e. just returns with proper flags), and then breakpoint it in wabbitemu. Then make a basic program that looks like this, dim(L1:dim(L1:5->dim(L1:5->dim(L1. Run the basic program and figure out how the parser handles dim(. It is either going to be a type 1, 2, or 3 type command, or a combo of 2 and 3. After you have the type, figure out what value of BC it passes to the hook. From here you can write your real parser hook which pops the list off the floating point stack and does it's thing.

Oh, I see. If you want to get hold of the arguments preparsed, then you need to use the mode 0, and go parse them yourself.

Using those three variables mentioned on the wikiTi page, you can find the information in ram, do what you want with it, and then let the parser go. What I did for some of my parser hooks was to completely relocate the tokens somewhere else. But I think since I didn't put the pointers back to their proper locations, I broke all basic programs.