Operators and Arithmetic

Whim checks operator types at runtime. It does not turn strings or booleans into numbers.

Integer arithmetic

+, -, and * return int when both operands are int. Whim checks overflow and underflow:

assert!(2 + 3 == 5);
assert!(2 - 3 == -1);
assert!(2 * 3 == 6);

An out-of-range result throws OverflowError or UnderflowError. Unary -, ++, and -- use the same checks.

If either operand of +, -, or * is float, the result is float:

assert!(1 + 0.5 == 1.5);
assert!(2.0 * 3 == 6.0);

Division and remainder

/ always returns float:

assert!(10 / 2 == 5.0);
assert!(7 / 2 == 3.5);

% accepts ints only. Its result has the sign of the left operand:

assert!(7 % 2 == 1);
assert!(-7 % 2 == -1);

Division or remainder by zero throws DivisionByZeroError, including float division by zero.

Powers

** is right-associative. An int base and a nonnegative int exponent produce an int when the result fits. A negative exponent or any float operand produces a float:

assert!(2 ** 10 == 1024);
assert!(2 ** -1 == 0.5);
assert!(2.0 ** 2 == 4.0);

Integer overflow throws. 0 ** -1 throws DivisionByZeroError.

Bit operators

&, |, ^, ~, <<, and >> accept ints only. A shift count must be from 0 through 63. Left shift uses the 64-bit bit pattern, so its result may wrap from positive to negative.

Increment and decrement

Prefix ++$value changes the target and returns the new value. Postfix $value++ returns the old value. -- follows the same rule. These operators accept int and float targets.

Boolean operators

!, &&, and || accept bool. && skips its right side when the left side is false. || skips it when the left side is true.

Concatenation

. joins strings, ints, and floats as text. It rejects other values.

Comparison and type operators

Equality and Order covers ==, !=, <, <=, >, >=, and <=>.

is, as, and ?as check a runtime type. These operators and comparisons do not chain.

Binding order

The full precedence table appears in the operator appendix. When the order is not plain, use parentheses. They cost nothing and state the intended order.