Arithmetic

Numeric variables are scoreboard integers. Arithmetic compiles to scoreboard players operation commands on the pack’s <namespace>.vars objective.

def calculate():
    a = 10
    b = 3

    total = a + b        # 13
    diff = a - b         # 7
    product = a * b      # 30
    quotient = a / b     # 3
    remainder = a % b    # 1
    power = b ^ 3        # 27

    mixed = a + b * 2 - a / 5   # 14, standard precedence

    a += 1               # same as a = a + 1
    a -= 1
    a *= 2
    a /= 2
    a %= 3
    b ^= 2

Precedence

From highest to lowest:

1. ^ (power), right to left
2. *, /, %, left to right
3. +, -, left to right
4. ==, !=, <, <=, >, >=

How Expressions Compile

• Constant operands go through helper fake players such as #multiplier, #divisor, and #modulus, because scoreboard players operation only takes scores.
• Intermediate results use fake players such as #expr_temp_<n>.
• A power with a constant exponent is expanded at compile time: x ^ 3 becomes x * x * x.
• A power with a runtime exponent calls a generated helper function. A negative runtime exponent gives 0, since scores cannot hold fractions.
• Compound assignment works on variables and storage-backed targets. x += y compiles as x = x + y.
• Expressions made only of constants are folded at compile time.

Integer Division And Modulo

/ and % follow Minecraft’s scoreboard /= and %=: division rounds toward negative infinity, and modulo is a floor modulus whose sign follows the divisor. Constant folding uses the same rules, so a folded expression and the same expression computed from variables agree:

a = -7 / 2      # -4
b = -7 % 3      # 2
c = 1 / 3 * 3   # 0, each step is integer arithmetic

const declarations are compile-time values that raw commands may substitute, so / in a const declaration is real division: const HALF = 1 / 2 substitutes 0.5 into {HALF}. % is the same floor modulus there. Storing a fractional constant in a score truncates it, with a precision warning.

Division By Zero

Dividing by a constant zero is a compile error:

Division by zero in constant expression: 10 / 0

A divisor that is only known at runtime is not checked. Minecraft rejects the operation, the command fails, and the target keeps the left operand’s value, so 10 / b with b = 0 leaves 10. Check the divisor first:

def share(total, players):
    if players != 0:
        each = total / players
    else:
        each = 0