The PathPilot G-code interpreter has a good feature set, where you can do math, define variables, and do conditionals and loops.
I have some utility programs where I for example set up stock width/thickness and it machines off the rough edges out of the saw.
That "setup" has to be done by editing the text file to set the parameters, though, there's no built-in "pop up a dialog" feature that I know of.
All the "conversational" dialog wizards in the controller are built-into the PathPilot software.

If you need a dialog, then I can think of two options.
One is to install some LinuxCNC GUI add-on (there's something called QTvcp for example)
You would then re-configure the HAL files to read the virtual "pins" that those widgets would control.

The other is to develop an M-code macro program in Python, and install it as part of PathPilot.

Both of these require Linux programming experience, and the first one additionally requires wanting to deal with HAL files.
Both of them would have to be re-applied each time you update the version of PathPilot, too, although the custom M-code one might be easier to do that with.