// // 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 }