Zig's interface? - tagged union

const std = @import("std");

const Animal = union(enum) {
    cat: Cat,
    dog: Dog,

    pub fn talk(self: Animal) void {
        switch (self) {
            inline else => |case| case.talk(),
        }
    }
};

const Cat = struct {
    anger_level: usize,

    pub fn talk(self: Cat) void {
        std.debug.print("[Cat] Meow! (anger Lv {})\n", .{self.anger_level});
    }
};

const Dog = struct {
    name: []const u8,

    pub fn talk(self: Dog) void {
        std.debug.print("[Dog] I'm a {s}\n", .{self.name});
    }
};

pub fn main() !void {
    const cat = Animal{ .cat = .{ .anger_level = 100 } };
    cat.talk();
    const dog = Animal{ .dog = .{ .name = "lilly" } };
    dog.talk();

    const animals = [_]Animal{
        cat,
        dog,
    };

    for (animals) |a| {
        a.talk();
    }
}