enum

Shell

1/7 test "enum ordinal value"... OK
2/7 test "set enum ordinal value"... OK
3/7 test "enum method"... OK
4/7 test "enum variant switch"... OK
5/7 test "std.meta.Tag"... OK
6/7 test "@typeInfo"... OK
7/7 test "@tagName"... OK
All 7 tests passed.

See also:

• @tagName

By default, enums are not guaranteed to be compatible with the C ABI:

test.zig

export fn entry(foo: Foo) void { _ = foo; }

For a C-ABI-compatible enum, provide an explicit tag type to the enum:

test.zig

const Foo = enum(c_int) { a, b, c };
export fn entry(foo: Foo) void { _ = foo; }

Shell

$ zig build-obj test.zig

Enum literals allow specifying the name of an enum field without specifying the enum type:

Shell

1/2 test "enum literals"... OK
2/2 test "switch using enum literals"... OK
All 2 tests passed.

A Non-exhaustive enum can be created by adding a trailing ‘_‘ field. It must specify a tag type and cannot consume every enumeration value.

@intToEnum on a non-exhaustive enum involves the safety semantics of to the integer tag type, but beyond that always results in a well-defined enum value.

A switch on a non-exhaustive enum can include a ‘_‘ prong as an alternative to an else prong with the difference being that it makes it a compile error if all the known tag names are not handled by the switch.

const std = @import("std");
const expect = std.testing.expect;
const Number = enum(u8) {
    one,
    two,
    three,
};
test "switch on non-exhaustive enum" {
    const number = Number.one;
    const result = switch (number) {
        .one => true,
        .two,
        .three => false,
        _ => false,
    };
    try expect(result);
    const is_one = switch (number) {
        .one => true,
        else => false,
    };
}

Shell