Rerolling only once or selectable number of times

Right now it's not possible to reroll only once or twice or etc. The rerolling command "r" will keep on rerolling the chosen number(s) until you get something else. Many games have some rules where you get to reroll eg number 1 but only once and you have to use the rerolled result regardless of what it is. It would be nice if the reroll command would get an additional parameter for how many times the dice are meant to be rerolled or at least a variant commant which would reroll only once. An example where I would need this is WFB where there are several "reroll only once" -rules eg. Murderous Prowess.

For clarity, this is specifically about "reroll and take the second result" type mechanics, not "reroll and take the best" or "reroll and take the worst." The latter two forms are possible via keep-high and keep-low, but the former is not possible without the API.

Brian is 100 % correct. The reason I didn't feel it needed additional clarification is that imo "reroll and thake the best/worst" is not rerolling anything it's rolling twice and keeping the better/worse result. To me rerolling is something where you first roll and then you reroll that same roll meaning the original roll never really happened since before its result was applied it got rerolled.