Equality and Order

Whim does not convert either side of an equality check.

Equality

== tests equality. != tests its opposite:

assert!(1 == 1);
assert!(1 != 1.0);
assert!(1u != 1);
assert!(1u != 1.0);
assert!('1' != 1);
assert!(0 != false);
assert!('' != null);

Two vecs or tuples are equal when their kinds, sizes, and ordered values match. Two dicts are equal when they hold the same strict keys and equal values. Dict insertion order does not affect equality:

assert!(vec[1, 2] != vec[2, 1]);
assert!((1, 2) != (2, 1));
assert!(dict['a' => 1, 'b' => 2] == dict['b' => 2, 'a' => 1]);

Objects and callables compare by identity:

final class Token {}

$token = new Token();
$same = $token;

assert!($token == $same);
assert!($token != new Token());

$callable = fn(): int => 1;
assert!($callable == $callable);
assert!($callable != fn(): int => 1);

Enum cases are single values. A case equals itself and not another case.

Float details

Positive and negative floating zero are equal. NaN is not equal to any value, including itself.

Order operators

<, <=, >, and >= compare:

• any pair of int, uint, and float;
• string with string, in byte order.

Other pairs throw IncompatibleOperandsError. Arrays, objects, callables, bool, and null have no built-in order.

assert!(1 < 2);
assert!(1 < 2.0);
assert!('apple' < 'banana');
assert!('10' < '9');

A comparison with NaN is false.

Numeric ordering compares mathematical values without first rounding integers to float. It can find equal magnitudes where strict equality is false:

assert!(1u <= 1);
assert!((1u <=> 1) == 0);
assert!(0u > -1);
assert!(9_007_199_254_740_993u > 9_007_199_254_740_992.0);
assert!(Whim\Math\UINT_MAX < 18_446_744_073_709_551_616.0);

Three-way comparison

<=> returns -1, 0, or 1 under the same order rules:

assert!((1 <=> 2) == -1);
assert!((2 <=> 2) == 0);
assert!(('b' <=> 'a') == 1);

It throws when either number is NaN.

Comparison operators do not chain. Write 1 < $value && $value < 10. The parser rejects 1 < $value < 10.