Toggle a boolean within a struct in zig, possible? - zig

Question

To toggle* a boolean I normally use boolean = !boolean like this:
var boolean: bool = true;
boolean = !boolean;
std.debug.print("My bool is: {}\n", .{boolean}); //My bool is: false
But how do I achieve this for booleans within a struct? Or is it not possible?
const std = #import("std");
pub fn main() void {
//Struct with default values:
const animal = struct {
tail: bool = true,
wings: bool = false,
horns: bool = false,
paws: bool = true,
};
//Struct instances:
var has = animal{};
//This works alright:
//var hasno = animal{.tail = false, .wings = true, .horns = true, .paws = false};
//FAILS: error: expected type 'bool', found '#TypeOf(.enum_literal)'
var hasno = animal{ .tail = !.tail }; //, .wings = !.wings, .horns = !.horns, .paws = !.paws };
//Debug printing:
std.debug.print("Animal has tail: {}, wings: {}, horns: {}, paws: {}\n", .{ has.tail, has.wings, has.horns, has.paws });
std.debug.print("Animal has no tail: {}, wings: {}, horns: {}, paws: {}\n", .{ hasno.tail, hasno.wings, hasno.horns, hasno.paws });
}
Test code for yourself online in zig playground:
https://zig-play.dev
*give it the opposite value of what it was, without knowing what it was.
Like if (boolean == true) boolean = false; else boolean = true; But I'm wondering if it is possible with the (bang) operator for booleans within struct.

Answer 1

const std = #import("std");
const Animal = struct {
tail: bool,
};
pub fn main() void {
var animal = Animal { .tail = true };
std.debug.print("{}\n", .{ animal });
animal.tail = !animal.tail;
std.debug.print("{}\n", .{ animal });
}
Prints:
main.Animal{ .tail = true }
main.Animal{ .tail = false }