Have roll set up in mind- Not sure if it can be done with a Macro or if it would require API

Looking for a some help for a macro for a homebrew game I am planning. Honestly not sure how difficult it would be. What I am hoping to do would be to set up the number of various dice so it could be tweaked in a drop down when rolled. Specifically with "x" being the number of dice to be rolled in the following: (xd6+xd12+xd4) - (xd8+xd20) If it requires an API will post in that Forum instead.  Regardless any help would be appreciated.

If x is the same number in all of them, you can just use a query. /roll (?{Number of Dice?|1}d6+?{Number of Dice?}d12+?{Number of Dice?}d4)-(?{Number of Dice?}d8+?{Number of Dice?}d20} If you want a dropdown to select the dice you can do it too: /roll (?{Number of Dice?|1|2|3|4|5}d6+?{Number of Dice?}d12+?{Number of Dice?}d4)-(?{Number of Dice?}d8+?{Number of Dice?}d20} Note that the first time you use a query, you need to include all options, but each extra time you use it, you just need to use the name. And the name is everything before the first |, including the ? if you use one as I did here.

It would be the latter. Thank you so much for the assistance and quick response! 

Unfortunately the second one only had one dropdown and all rolled that number of dice. Like the first one, just a drop-down rather than typing the number in the box. I'd like to be able to select, for example, (2d6+1d12+0d4) - (1d8+1d20) for one roll and then change the numbers for something like (2d6+0d12+3d4) - (3d8+0d20) 

You'll need to have each query run separately in that case: /roll (?{Number of d6|0|1|2|3|4|5}d6+?{Number of d12|0|1|2|3|4|5}d12+?{Number of d4|0|1|2|3|4|5}d4)-(?{Number of d8|0|1|2|3|4|5}d8+?{Number of d20|0|1|2|3|4|5}d20})

That worked! Thank you so much! Guessing to have the selections as separate boxes all up at the same time would require an API.

No, that's not even possible with the API. It's a design limitation of roll20, you can only have one dropdown or query on screen at a time.

That is too bad, but good to know. Thanks for letting me know.

You could use a token's properties GUI as a pseudo-query box... probably more hassle than it is worth but using bar1 value through to bar3 max to represent the dice query in ascending order you'd do: /roll (@{selected|bar1|max}d6 + @{selected|bar3}d12 + @{selected|bar1}d4)-(@{selected|bar2}d8 + @{selected|bar3|max}d20}) You'd need to have the token selected and edit the actual bar values and max values ahead of time but it would  be a single hit query GUI?

Will have to try that out. Sooner or later will have to get some help making a sheet for the system, just figured this sort of thing would be an easier ask for now.