Scores

namespace demo;

var #mana = 0;

mcfun regen() {
    if (@s.#mana < 100) {
        @s.#mana = @s.#mana + 5;
    }
}

A # variable is a scoreboard score: a 32-bit integer. Math wraps on overflow, and / and % round down.

• A global #mana has its own dummy objective, <namespace>.mana, which poplar/load adds.
• #mana on its own is the global value, held by the fake player #global. The sidebar hides it.
• @s.#mana is an entity’s value in the same objective. Any selector works: @p.#mana, @a.#mana.
• A local is the fake player #<name>_<function> in the objective poplar.<namespace>.

Scores support + - * / % and the comparisons < <= > >= == !=. The example above compiles to one command:

execute if score @s demo.mana matches ..99 run scoreboard players add @s demo.mana 5

To read an entity score, the selector must name one entity: @s, @p, @r, @n, or a selector with limit=1. You can write to many entities at once (@a.#mana = 0;).

Costs and caveats

• Each global # variable adds one objective to the world.
• /reload keeps values. A global’s initial value is only set when #global has no value, so changing it in your code doesn’t change an existing world. Entities get no initial value.
• A local costs one command per declaration to set its value. Locals have no entity values, so @s.#i is an error when #i is local.