const expect = @import("std").testing.expect; const mem = @import("std").mem; const fmt = @import("std").fmt; const ET = union(enum) { SINT: i32, UINT: u32, pub fn print(a: *const ET, buf: []u8) anyerror!usize { return switch (a.*) { ET.SINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}), ET.UINT => |x| fmt.formatIntBuf(buf, x, 10, false, fmt.FormatOptions{}), }; } }; test "enum with members" { const a = ET{ .SINT = -42 }; const b = ET{ .UINT = 42 }; var buf: [20]u8 = undefined; try expect((a.print(buf[0..]) catch unreachable) == 3); try expect(mem.eql(u8, buf[0..3], "-42")); try expect((b.print(buf[0..]) catch unreachable) == 2); try expect(mem.eql(u8, buf[0..2], "42")); }