#box #beginner #tutorial #gift #instructional


A fun Rust crate called giftbox to help Rustlings learn and explore generics

1 unstable release

0.1.1 Oct 7, 2021

#890 in Data structures

MIT license

227 lines

GiftBox A fun Rust crate to help Rustlings learn and explore generics.


The purpose of this crate is to:

  • Help Rustlings understand Rust generics and how to use them.
  • Expand upon related beginner topics to support a Rustling's understanding of generics.
  • Provide a fun crate to be used in hands-on self-directed Rustling projects to assist the learning process.
  • Be approachable, supportive, and encourage participation in a GiftBox community.


This crate uses the concept of a gift box to help explain Rust generics.

Imagine a real-life gift box. You can put any gift inside this gift box, wrap this gift box with wrapping paper, add a bow, and add a gift tag to show who it is for, who it is from and a short message. The gift box is generic, so you can reasonably assume that you can use this gift box to put any gift inside.

Imagine more, if you will, that Rust's compiler is like the gift wrapping station at your local shopping mall. This imaginary gift wrapping station already has gift boxes for every type of gift available in the shopping mall. It can also build a new gift box on demand to put inside other gifts that you bring to them, which may not be already in the shopping mall. This gift wrapping station is so exceptional that they can pretty much put any gift you bring to them in a gift box.

Once your gift box is filled with a gift, it can then be gift wrapped or not. If it is wrapped it can have different patterns available at the gift wrapping station. You can also decide to add a gift tag or not.

In this way, the gift box is a generic. It is generic enough so that you can use it to wrap a huge--almost limitless--number of different things inside it. We will use this concept of the gift box to help describe what generics are in Rust.

Associating the Concept with Rust Concepts

Sometimes a metaphor can assist in the learning process. Metaphors help abstract difficult concepts so that the learner can relate these difficult concepts to other concepts that they may already be accustomed to. It is in this way that this crate uses the gift box metaphor to describe what a Rust generic is.

In order for the use of metaphors to work best, and to help reduce confusion, let's relate the metaphors to the Rust concepts we are trying to learn:

  • rustc The Rust Compiler

    The Rust compiler, in this example, can be thought of as the gift wrapping station. When compiling a program that has generics, the compiler needs to know what the generics are being used for in order to allocate the appropriate amount of memory. In this same way, the gift wrapping station needs to know what gift (or at least what type of gift) is being wrapped so that they know which sized box they should use. If the gift wrapping station uses a box that is too big, the box will be inefficient and more difficult to carry than it needs to be. If the box is too small, the gift might not even fit in the box at all!

  • Generics Rust Generic Data Types

    In Rust, a generic is a generalized type or functionality that can be used for different types. "Wait, what?!", you might ask. Think of generics as the gift box. A gift box is normally generic enough that it can be used for a large variety of gifts, as long as the gift box is sized correctly. The versatility of the gift box allows it to be useful in a large number of contexts. For example, a gift box can be used for many different occasions such as a birthday, Christmas, or an anniversary and hold many different types of gifts like a book, or toys, or candy, or many different things all at once! Therefore, similar to Rust generics, the gift box is a real-life "generic".


Add this to your Cargo.toml:

giftbox = "0.1.1"

Here's a simple example that creates a newly filled GiftBox that is wrapped, has a bow, and has a gift tag:

use giftbox::giftbox::GiftBox;
use giftbox::gifttag::GiftTag;
use giftbox::giftwrap::GiftWrap;
use giftbox::patterns::Patterns;

let filled_box = GiftBox::fill(Some(["Toys", "Candy", "Money"]));
let tag = GiftTag::write(
    "Happy Cake Day!".to_string()
let wrapped_box = filled_box.wrap(

         GiftWrap {
                 GiftBox::Gifts(["Toys", "Candy", "Money"])
             pattern: Patterns::Polkadots,
             has_bow: true,
             tag: Some(
                 GiftTag {
                     recipient: "Bob".to_string(),
                     sender: "Sally".to_string(),
                     message: "Happy Cake Day!".to_string()

Participation and Contributions

Any and all participation is welcome with the project. It is meant to be fun and useful for all programmers who are new to Rust. If you have found this to be of benefit in your Rust learning journey or would like to enhance this project with your expertise, please do!

Please consider opening an issue before making pull requests.

Areas that this project could benefit most:

  • Adding more useful beginner examples, features and functionality throughout the project.
  • Enhancing and writing more documentation that is beginner-friendly.
  • Creating other crates that utilize GiftBox so that the value of generics is better understood in the Rust ecosystem.
  • Finding and reporting bugs and issues.

Most of all, this project would benefit most by sharing it with your friends and building a community!


This project is licensed under the MIT License.

No runtime deps