exercises/README.md

# Ziglings

Welcome to Ziglings! This project contains a series of tiny broken programs (and one nasty surprise).
By fixing them, you'll learn how to read and write [Zig](https://ziglang.org/) code.

![ziglings](https://user-images.githubusercontent.com/1458409/109398392-c1069500-790a-11eb-8ed4-7d7d74d32666.jpg)

Those broken programs need your help! (You'll also save the planet from
evil aliens and help some friendly elephants stick together, which is very
sweet of you.)

This project was directly inspired by the brilliant and fun
[rustlings](https://github.com/rust-lang/rustlings)
project for the [Rust](https://www.rust-lang.org/) language.
Indirect inspiration comes from [Ruby Koans](http://rubykoans.com/)
and the Little LISPer/Little Schemer series of books.

## Intended Audience

This will probably be difficult if you've _never_ programmed before.
But no specific programming experience is required. And in particular,
you are _not_ expected to have any prior experience with "systems programming"
or a "systems" level language such as C.

Each exercise is self-contained and self-explained. However, you're encouraged
to also check out these Zig language resources for more detail:

* https://ziglang.org/learn/
* https://ziglearn.org/
* https://ziglang.org/documentation/master/

Also, the [Zig community](https://github.com/ziglang/zig/wiki/Community) is incredibly friendly and helpful!

## Getting Started

Install a [development build](https://ziglang.org/download/) of the Zig compiler.
(See the "master" section of the downloads page.)

Verify the installation and build number of `zig` like so:

```
$ zig version
0.11.0-dev.2560+xxxxxxxxx
```

Clone this repository with Git:

```
$ git clone https://github.com/ratfactor/ziglings
$ cd ziglings
```

Then run `zig build` and follow the instructions to begin!

```
$ zig build
```

## A Note About Versions

The Zig language is under very active development. In order to be current,
Ziglings tracks **development** builds of the Zig compiler rather than
versioned **release** builds. The last stable release was `0.10.1`, but Ziglings
needs a dev build with pre-release version "0.11.0" and a build number at least
as high as that shown in the example version check above.

It is likely that you'll download a build which is _greater_ than the minimum.

_(For those who cannot easily update Zig, there are also community-supported
branches in this repo. At the moment, there's one for v0.8.1. Older version
branches may or may not have all exercises and/or bugfixes.)_

Once you have a build of the Zig compiler that works with Ziglings, they'll
continue to work together. But keep in mind that if you update one, you may
need to also update the other.

Also note that the current "stage 1" Zig compiler is very strict
about input: 
[no tab characters or Windows CR/LF newlines are allowed](https://github.com/ziglang/zig/issues/544).

### Version Changes

Version-0.11.0-dev.2560+602029bb2
* *2023-04-07* zig 0.11.0-dev.2401 - fixes of the new build system - see [#212](https://github.com/ratfactor/ziglings/pull/212)
* *2023-02-21* zig 0.11.0-dev.2157 - changes in `build system` - new: parallel processing of the build steps
* *2023-02-21* zig 0.11.0-dev.1711 - changes in `for loops` - new: Multi-Object For-Loops + Struct-of-Arrays
* *2023-02-12* zig 0.11.0-dev.1638 - changes in `std.Build` cache_root now returns a directory struct
* *2023-02-04* zig 0.11.0-dev.1568 - changes in `std.Build` (combine `std.build` and `std.build.Builder` into `std.Build`)
* *2023-01-14* zig 0.11.0-dev.1302 - changes in `@addWithOverflow` (now returns a tuple) and `@typeInfo`; temporary disabled async functionality
* *2022-09-09* zig 0.10.0-dev.3978 - change in `NativeTargetInfo.detect` in build
* *2022-09-06* zig 0.10.0-dev.3880 - Ex 074 correctly fails again: comptime array len
* *2022-08-29* zig 0.10.0-dev.3685 - `@typeName()` output change, stage1 req. for async
* *2022-07-31* zig 0.10.0-dev.3385 - std lib string `fmt()` option changes
* *2022-03-19* zig 0.10.0-dev.1427 - method for getting sentinel of type changed
* *2021-12-20* zig 0.9.0-dev.2025 - `c_void` is now `anyopaque`
* *2021-06-14* zig 0.9.0-dev.137  - std.build.Id `.Custom` is now `.custom`
* *2021-04-21* zig 0.8.0-dev.1983 - std.fmt.format() `any` format string required
* *2021-02-12* zig 0.8.0-dev.1065 - std.fmt.format() `s` (string) format string required

## Advanced Usage

It can be handy to check just a single exercise or _start_ from a single
exercise:

```
zig build -Dn=19
zig build -Dn=19 start
```

You can also run without checking for correctness:

```
zig build -Dn=19 test
```

Or skip the build system entirely and interact directly with the compiler
if you're into that sort of thing:

```
zig run exercises/001_hello.zig
```

Calling all wizards: To prepare an executable for debugging, install it
to zig-cache/bin with:

```
zig build -Dn=19 install
```

To get a list of all possible options, run:

```
zig build -Dn=19 -l

  install                      Install 019_functions2.zig to prefix path
  uninstall                    Uninstall 019_functions2.zig from prefix path
  test                         Run 019_functions2.zig without checking output
  ...
```

## What's Covered

The primary goal for Ziglings is to cover the core Zig language.

It would be nice to cover the Standard Library as well, but this
is currently challenging because the stdlib is evolving even
faster than the core language (and that's saying something!).
Not only would stdlib coverage change very rapidly, some exercises might even cease to be relevant entirely.

Having said that, there are some stdlib features that are probably here
to stay or are so important to understand that they are worth the
extra effort to keep current.

Conspicuously absent from Ziglings are a lot of string
manipulation exercises. This is because Zig itself largely avoids
dealing with strings. Hopefully there will be an obvious way to
address this in the future. The Ziglings crew loves strings!

Zig Core Language

* [x] Hello world (main needs to be public)
* [x] Importing standard library
* [x] Assignment
* [x] Arrays
* [x] Strings
* [x] If
* [x] While
* [x] For
* [x] Functions
* [x] Errors (error/try/catch/if-else-err)
* [x] Defer (and errdefer)
* [x] Switch
* [x] Unreachable
* [x] Enums
* [x] Structs
* [x] Pointers
* [x] Optionals
* [x] Struct methods
* [x] Slices
* [x] Many-item pointers
* [x] Unions
* [x] Numeric types (integers, floats)
* [x] Labelled blocks and loops
* [x] Loops as expressions
* [x] Builtins
* [x] Inline loops
* [x] Comptime
* [x] Sentinel termination
* [x] Quoted identifiers @""
* [x] Anonymous structs/tuples/lists
* [ ] Async <--- IN PROGRESS!
* [X] Interfaces

Zig Standard Library

* [X] Working with C
* [X] String formatting
* [X] Bit manipulation

## Contributing

Contributions are very welcome! I'm writing this to teach myself and to create
the learning resource I wished for. There will be tons of room for improvement:

* Wording of explanations
* Idiomatic usage of Zig
* Additional exercises

Please see [CONTRIBUTING](https://github.com/ratfactor/ziglings/blob/main/CONTRIBUTING.md) in this repo for the full details.