zig/test/cases/enum.zig

const assert = @import("std").debug.assert;
const mem = @import("std").mem;

test "enum type" {
    const foo1 = Foo.One {13};
    const foo2 = Foo.Two { Point { .x = 1234, .y = 5678, }};
    const bar = Bar.B;

    assert(bar == Bar.B);
    assert(@memberCount(Foo) == 3);
    assert(@memberCount(Bar) == 4);
    assert(@sizeOf(Foo) == @sizeOf(FooNoVoid));
    assert(@sizeOf(Bar) == 1);
}

test "enum as return value" {
    switch (returnAnInt(13)) {
        Foo.One => |value| assert(value == 13),
        else => unreachable,
    }
}

const Point = struct {
    x: u64,
    y: u64,
};
const Foo = enum {
    One: i32,
    Two: Point,
    Three: void,
};
const FooNoVoid = enum {
    One: i32,
    Two: Point,
};
const Bar = enum {
    A,
    B,
    C,
    D,
};

fn returnAnInt(x: i32) -> Foo {
    Foo.One { x }
}


test "constant enum with payload" {
    var empty = AnEnumWithPayload.Empty;
    var full = AnEnumWithPayload.Full {13};
    shouldBeEmpty(empty);
    shouldBeNotEmpty(full);
}

fn shouldBeEmpty(x: &const AnEnumWithPayload) {
    switch (*x) {
        AnEnumWithPayload.Empty => {},
        else => unreachable,
    }
}

fn shouldBeNotEmpty(x: &const AnEnumWithPayload) {
    switch (*x) {
        AnEnumWithPayload.Empty => unreachable,
        else => {},
    }
}

const AnEnumWithPayload = enum {
    Empty,
    Full: i32,
};



const Number = enum {
    Zero,
    One,
    Two,
    Three,
    Four,
};

test "enum to int" {
    shouldEqual(Number.Zero, 0);
    shouldEqual(Number.One, 1);
    shouldEqual(Number.Two, 2);
    shouldEqual(Number.Three, 3);
    shouldEqual(Number.Four, 4);
}

fn shouldEqual(n: Number, expected: usize) {
    assert(usize(n) == expected);
}


test "int to enum" {
    testIntToEnumEval(3);
}
fn testIntToEnumEval(x: i32) {
    assert(IntToEnumNumber(x) == IntToEnumNumber.Three);
}
const IntToEnumNumber = enum {
    Zero,
    One,
    Two,
    Three,
    Four,
};


test "@enumTagName" {
    assert(mem.eql(u8, testEnumTagNameBare(BareNumber.Three), "Three"));
    comptime assert(mem.eql(u8, testEnumTagNameBare(BareNumber.Three), "Three"));
}

fn testEnumTagNameBare(n: BareNumber) -> []const u8 {
    return @enumTagName(n);
}

const BareNumber = enum {
    One,
    Two,
    Three,
};


test "enum alignment" {
    comptime {
        assert(@alignOf(AlignTestEnum) >= @alignOf([9]u8));
        assert(@alignOf(AlignTestEnum) >= @alignOf(u64));
    }
}

const AlignTestEnum = enum {
    A: [9]u8,
    B: u64,
};

const ValueCount0 = enum {};
const ValueCount1 = enum { I0 };
const ValueCount2 = enum { I0, I1 };
const ValueCount256 = enum {
    I0, I1, I2, I3, I4, I5, I6, I7, I8, I9, I10, I11, I12, I13, I14, I15,
    I16, I17, I18, I19, I20, I21, I22, I23, I24, I25, I26, I27, I28, I29, I30, I31,
    I32, I33, I34, I35, I36, I37, I38, I39, I40, I41, I42, I43, I44, I45, I46, I47,
    I48, I49, I50, I51, I52, I53, I54, I55, I56, I57, I58, I59, I60, I61, I62, I63,
    I64, I65, I66, I67, I68, I69, I70, I71, I72, I73, I74, I75, I76, I77, I78, I79,
    I80, I81, I82, I83, I84, I85, I86, I87, I88, I89, I90, I91, I92, I93, I94, I95,
    I96, I97, I98, I99, I100, I101, I102, I103, I104, I105, I106, I107, I108, I109,
    I110, I111, I112, I113, I114, I115, I116, I117, I118, I119, I120, I121, I122, I123,
    I124, I125, I126, I127, I128, I129, I130, I131, I132, I133, I134, I135, I136, I137,
    I138, I139, I140, I141, I142, I143, I144, I145, I146, I147, I148, I149, I150, I151,
    I152, I153, I154, I155, I156, I157, I158, I159, I160, I161, I162, I163, I164, I165,
    I166, I167, I168, I169, I170, I171, I172, I173, I174, I175, I176, I177, I178, I179,
    I180, I181, I182, I183, I184, I185, I186, I187, I188, I189, I190, I191, I192, I193,
    I194, I195, I196, I197, I198, I199, I200, I201, I202, I203, I204, I205, I206, I207,
    I208, I209, I210, I211, I212, I213, I214, I215, I216, I217, I218, I219, I220, I221,
    I222, I223, I224, I225, I226, I227, I228, I229, I230, I231, I232, I233, I234, I235,
    I236, I237, I238, I239, I240, I241, I242, I243, I244, I245, I246, I247, I248, I249,
    I250, I251, I252, I253, I254, I255
};
const ValueCount257 = enum {
    I0, I1, I2, I3, I4, I5, I6, I7, I8, I9, I10, I11, I12, I13, I14, I15,
    I16, I17, I18, I19, I20, I21, I22, I23, I24, I25, I26, I27, I28, I29, I30, I31,
    I32, I33, I34, I35, I36, I37, I38, I39, I40, I41, I42, I43, I44, I45, I46, I47,
    I48, I49, I50, I51, I52, I53, I54, I55, I56, I57, I58, I59, I60, I61, I62, I63,
    I64, I65, I66, I67, I68, I69, I70, I71, I72, I73, I74, I75, I76, I77, I78, I79,
    I80, I81, I82, I83, I84, I85, I86, I87, I88, I89, I90, I91, I92, I93, I94, I95,
    I96, I97, I98, I99, I100, I101, I102, I103, I104, I105, I106, I107, I108, I109,
    I110, I111, I112, I113, I114, I115, I116, I117, I118, I119, I120, I121, I122, I123,
    I124, I125, I126, I127, I128, I129, I130, I131, I132, I133, I134, I135, I136, I137,
    I138, I139, I140, I141, I142, I143, I144, I145, I146, I147, I148, I149, I150, I151,
    I152, I153, I154, I155, I156, I157, I158, I159, I160, I161, I162, I163, I164, I165,
    I166, I167, I168, I169, I170, I171, I172, I173, I174, I175, I176, I177, I178, I179,
    I180, I181, I182, I183, I184, I185, I186, I187, I188, I189, I190, I191, I192, I193,
    I194, I195, I196, I197, I198, I199, I200, I201, I202, I203, I204, I205, I206, I207,
    I208, I209, I210, I211, I212, I213, I214, I215, I216, I217, I218, I219, I220, I221,
    I222, I223, I224, I225, I226, I227, I228, I229, I230, I231, I232, I233, I234, I235,
    I236, I237, I238, I239, I240, I241, I242, I243, I244, I245, I246, I247, I248, I249,
    I250, I251, I252, I253, I254, I255, I256
};

test "enum sizes" {
    comptime {
        assert(@sizeOf(ValueCount0) == 0);
        assert(@sizeOf(ValueCount1) == 0);
        assert(@sizeOf(ValueCount2) == 1);
        assert(@sizeOf(ValueCount256) == 1);
        assert(@sizeOf(ValueCount257) == 2);
    }
}

const Small2 = enum (u2) {
    One,
    Two,
};
const Small = enum (u2) {
    One,
    Two,
    Three,
    Four,
};

test "set enum tag type" {
    {
        var x = Small.One;
        x = Small.Two;
        comptime assert(@EnumTagType(Small) == u2);
    }
    {
        var x = Small2.One;
        x = Small2.Two;
        comptime assert(@EnumTagType(Small2) == u2);
    }
}