Two-Way exploding luck dice?

I am trying to understand rolls / macros. The game I want to play has a variable number of d6 rolled and summed up together with a modifier. That is no problem with /roll ?{dice}d6+?{modifier} and would not even require a macro. The tricky part is that the system uses a "luck" dice. Each 6 explodes multiple times. I guess this can be done by /roll 1d6!!6+(?{dice}-1)d6+?{modifier}. However the system also does a "negative explosion". If the lucky dice shows 1, it is re-rolled and the rhesult (and all subsequent explosions) subtracted from the total. How do i to that in roll20? Can I store the dice result and do an "if...then" query?

Currently, the only way to automate that system would be with an API script.  The API requires a Pro level subscription by the Game's Creator that will use it.   If you want to pursue that option, throw a script request post in the API forum with details and some examples.

Thanks for the quick reply... Can the API only be used buy this one game creator? Most WEG d6 games (e.g. StarWars d6) use this kind of roll.

Any scripts I write for the API would be general purpose and usable by any Roll20 Game whose Creator is a Pro level subscriber in any game that shared the same mechanics. =D

Good to know. Now I just need to find a scroll of "raise: undead" to get the old WEG crew to pay for it ;) Will think about it, may do it manually for now.

Writing the script for that won't be very difficult.  I've written quite a few dice mechanics scripts that are similar.  ZombieDice, MutantYearZero, CthulhutechDice, BashDice, etc... The Pro subscription I can't help you with though.  =D Drop a post in API if you want someone ( *cough* ) to see about writing one.  =D