Boolean operators

Onyx has the following binary boolean operators:

OperatorUseWorks on

Onyx has the following unary boolean operator:

OperatorUseWorks on

Implicit Boolean Conversions

In certain circumstances where a boolean value is expected, Onyx will implicitly convert the value to a boolean in the following ways:

  • Pointers: If the pointer is non-null, it is true. If it is null, it is false.
  • Array-like: If the array is empty, it is false. If it is non-empty, it is true.
  • Optionals: If the optional has a value, it is true. Otherwise, it is false.

As an escape-hatch for library writers, it is possible to make anything implicitly cast to bool by overloading the builtin procedure, __implicit_bool_cast. Here is an example of making a custom structure cast to bool implicitly.

Person :: struct {
    age: u32;
    name: str;

__implicit_bool_cast :: (p: Person) -> bool {
    return p.age > 0 &&;

main :: () {
    p1 := Person.{};
    p2 := Person.{42, "Joe"};

    if !p1 { println("p1 is false"); }
    if  p2 { println("p2 is true"); }