Keypad for setting custom timer

[Seeloewen]

While it's currently entirely possible to set a custom timer, both using the given options to add/remove seconds as well as just using the scoreboard command manually, it would be cool to have some sort of keypad to set a custom timer. Should theoretically be possible. You'd have 10 buttons, 1 for each number, as well as a button to confirm and backspace. The numbers would go into variables. When confirming, the numbers would be multiplied and added to form the correct output. Once again, this is not really something the datapack really needs or something that's important, more of a personal challenge. Could be added to the datapack soon, maybe not, maybe never.