Day 7: One week later

It has been a week since I started on the challenge of working 1000 days with Zig.

Enums

An “enum” is a Zig construct that lets you give names to numeric values and store them in a set. They look a lot like error sets, where a set means the values are unique.

  const Fruit = enum{ apple, pear, orange };
  const my_fruit = Fruit.apple;

Since enums are sets of numbers, you can have the compiler handle the numbering for you, or assign the numbers explicitly using a given type.

  const Stuff = enum(u8){ foo = 16 };

With enums one can get the integer using the built-in function @intFromEnum().

 const my_stuff: u8 = @intFromEnum(Stuff.foo);

Structs

Zig has the struct or structure functionality, where we may have this

point1_x = 3;
point1_y = 16;
point1_z = 27;
point2_x = 7;
point2_y = 13;
point2_z = 34;

Which through a struct can be changed into

point1 = Point{ .x=3, .y=16, .z=27 };
point2 = Point{ .x=7, .y=13, .z=34 };

The struct above can be defined as shown below:

const Point = struct{ x: u32, y: u32, z: u32 };

Through structs one is able to mimic the class functionality in Object Oriented Programming languages.

const std = @import("std");

const Role = enum {
    wizard,
    thief,
    bard,
    warrior,
};

const Character = struct {
    role: Role,
    gold: u32,
    health: u8,
    experience: u32,
};

pub fn main() void {
    var chars: [2]Character = undefined;

    // Glorp the Wise
    chars[0] = Character{
        .role = Role.wizard,
        .gold = 20,
        .health = 100,
        .experience = 10,
    };
    // Zump the Loud

    chars[1] = Character{
         .role = Role.bard,
         .gold = 10,
         .health = 100,
         .experience = 20,
     };

    for (chars, 0..) |c, num| {
        std.debug.print("Character {} - G:{} H:{} XP:{}\n", .{
            num + 1, c.gold, c.health, c.experience,
        });
    }
}

Above is an example showing usage of a struct and enum courtesy of Ziglings. Running the above without the chars[1], you will get values seeming like garbage. In Zig debug mode, Zig will write the repeating pattern “10101010” in binary (or 0xAA in hex) to all undefined locations to make them easier to spot when debugging.

What I Learned Today

• Enums and Structs in Zig

Looking Ahead

Tomorrow is Sunday; I will see what to work on as I embark on my 8th day doing Zig in my 1000-day journey.

References

1. Ziglings