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//
// It is really quite inconvenient having to manually keep track
// of the active field in our union, isn't it?
//
// Thankfully, Zig also has "tagged unions", which allow us to
// store an enum value within our union representing which field
// is active.
//
// const FooTag = enum{ small, medium, large };
//
// const Foo = union(FooTag) {
// small: u8,
// medium: u32,
// large: u64,
// };
//
// Now we can use a switch directly on the union to act on the
// active field:
//
// var f = Foo{ .small = 10 };
//
// switch (f) {
// .small => |my_small| do_something(my_small),
// .medium => |my_medium| do_something(my_medium),
// .large => |my_large| do_something(my_large),
// }
//
// Let's make our Insects use a tagged union (Doctor Zoraptera
// approves).
//
const std = @import("std");
const InsectStat = enum { flowers_visited, still_alive };
const Insect = union(InsectStat) {
flowers_visited: u16,
still_alive: bool,
};
pub fn main() void {
var ant = Insect{ .still_alive = true };
var bee = Insect{ .flowers_visited = 16 };
std.debug.print("Insect report! ", .{});
// Could it really be as simple as just passing the union?
printInsect(???);
printInsect(???);
std.debug.print("\n", .{});
}
fn printInsect(insect: Insect) void {
switch (???) {
.still_alive => |a| std.debug.print("Ant alive is: {}. ", .{a}),
.flowers_visited => |f| std.debug.print("Bee visited {} flowers. ", .{f}),
}
}
// By the way, did unions remind you of optional values and errors?
// Optional values are basically "null unions" and errors use "error
// union types". Now we can add our own unions to the mix to handle
// whatever situations we might encounter:
// union(Tag) { value: u32, toxic_ooze: void }
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