GPv2: Dice Strings

So it's been pointed out to me that the GP dice roller can sometimes be funky, and I wanted to bring up something that has been raised in the past: dice strings.

A lot of other online dice rollers roll dice with keys in the string you enter, and I'm considering if I should swap to that in the v2, stay the same as we have now, or go for a hybrid.

Lets look at Reroll Aces as an example. A potential dice string for that could be something like:

4d6[Ra]

This would tell the dice roller to roll 4d6, and reroll aces on all the dice rolled. Anything in the square brackets gets checked against valid options, for example we could add Adv for advantage or Dadv (I donno how much I like that) for disadvantage, a la DnD, or Ex for exploding dice.

We can also set dice type via a different type of key, which i was thinking would be in curly braces. So if you wanted to roll 4 Fate dice:

{F}4

(For Fate, maybe even allow someone to not enter a number, to default to 4). We'd have SWFFG, F, and FS for Star Wars FFG, Fate, and Feng Shui accordingly.

So I wanted to get people's thoughts. I'm not positive which if any to implement. I think the dice options ([]) idea is good, and we can have options for different dice types that need it. I think there's something to the dice type option as well, but maybe the current dropdown is good enough for that? Maybe I'm overthinking this entirely, and we just need the dice options for standard dice?

I like being able to automate rerolls based on results, and there's several roll and keep systems that could benefit from that, but I don't think it's a necessity. Leave your dice system open-ended, but only come back to it after you're done with your original rebuild goals.

I don't plan on making crazy big changes, but I bring this up now because if I'm writing new regex (the code that parses the string to determine what to roll), I'd rather do that once :p Plus, if people think I should simplify the UI, I'd rather not build it in the first place.

I like the proposed change for square brackets, but the curly bracket one seems more difficult syntax to remember (unless some kind of hover-help function accompanied out).

Dice addition and subtraction would be a great additional feature: 1d6+1d4+2 is fairly common for D&D (incl. clones) and Savage Worlds, for example.

Addition and subtraction would be great in D&D for spells like Bless and Bane: e.g. 1d20+5+1d4 or 1d20+5-1d4

I love the idea of bracketed or curly bracketed modifiers, would allow for several options:
[Kh#] = Keep Highest # Dice
[Kl#] = Keep Lowest # Dice
[Dh#] = Drop Highest # Dice
[Dl#] = Drop Lowest # Dice
[Ra] = Reroll Aces
[R()#] = Reroll # result a single time, could include [R

Oh, sorry, I didn't cover that in the OP, but yes, more advanced math will be coming.

That could be interesting. Personally, I think going with an hybrid system might be the best option. Those hoping to stick to the older system they feel more comfortable using could, and those feeling brave could use the bracket option.

I also wonder if there could be an option for "reverse aces", where a roll of 1 is treated like an ace. I know at least one system, which uses it, and there might be others out there.

(1D6×(3D4^(1D2+1)))/2D6

I like the idea of strings. Ex works for exploding, but the adv and disadvantage could be players just using the "keep highest" and "keep lowest" options on their d20 roll. though having a specific option for advantage and disadvantage isn't bad either.

I think the hybrid might be best as well -- as you can include that standard stuff you currently have -- then simply add a new type called Custom Rolls -- then as long as the options that were chosen are stated then there is never a doubt as to how something was rolled

This keeps the simplicity of what is and adds the extra feature as simply an addition to what is thus, hopefully, reducing the amount of coding that is going to go on behind the scenes -- btw you never did drop by that coders forum so we could discuss what you would like me to do ;) if you need that invite again let me know.

Hmm, I forgot about this because I'm not a mobile user, but keeping the hybrid solution might be the best option so that mobiles users can still roll their dice faster and more easily instead of having to deal with the hassle of entering all those brackets using their touchscreen keypad...

In that vein perhaps one can step up some kind of preset Custom Dice Rolls that get associated with a person's account then they can maybe set them up easily from a computer and then select them from a configurable drop down list associated with a specific game. This way all you need to do is create simple cross-reference indices for the "Custom Roll" with the option of designing one on the spot and saving it or not -- as well as going in and creating ones on ahead of time -- and perhaps maybe even share them with games you are running again all you would need is a cross-reference indices to do this at the point of use and everything else done in the back-ground