Rolling 1D8 and having the 8 side value equal to 0

Hi, For a character sheet I am currently working on, I want to make a roll button so that it rolls an explosive D8 on the 7th side (1D8!7) but the 8th value has to be consider as 0. For example, if you roll 7, you roll again and you get 8 on this second roll, the total roll result is 7 (7+8 = 7+0). The explosive part is no problem. However, I don't know how to manage the 8th side that has to be considered as 0. Any help welcome ! :) Regards :) Edit : plz note that I don't want to roll 1D7. The 0 value has to be integrated in the results.

This would require an API Script; would you like me to move this thread to the API forum?

Hi Silvyre ! Thx for the proposal. Since I want to integrate the roll button in a submitted character sheet, I don't want free Roll20 users to no be able to use it. So if an API script is the only option for my problem, I guess users will have to manually roll for this. :(

You could do a hacky version of this without the API using Roll Templates.  For an example of this you could look at the BASH character sheet. It requires people manually adding the totals, though. AND it would also potentially require additional dice being rolled manually, but you could catch a fair number off instances by figuring a die may explode 3 or 4 times on average (or however many times you think appropriate to catch the majority of instances).