Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

Welcome to the second week of 24 days of Rust! Hope you enjoy the articles so far. Today let me introduce you to racer - a code completion engine for Rust.

As there is no proper Rust IDE (yet), most of us Rustaceans use some code editor such as Vim, Emacs, Atom etc. However the out-of-the-box support for Rust is very limited - if you're lucky, your editor has syntax highlighting, but not much more. We'd love to have some sort of autocompletion to ease typing, and a "go to definition" command to quickly jump around the codebase.

Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

The itertools crate contains several utility functions and macros inspired by Haskell and Python itertools. As you can guess from the name, these have to do with iteration and iterators. Rust has recently split the Iterator trait into Iterator and IteratorExt for so called object safety reasons (see the RFC for an explanation). This is mostly irrelevant for today's episode of 24 days of Rust, but worth keeping in mind.

Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

JSON is a workhorse data format of the modern Web. Originating from the JavaScript world, it gained a lot of traction and at the moment it's usually the first choice of a Web developer for a data interchange format. Not only Web - once JavaScript-only, JSON support is now ubiquitous. A lot of languages ship with JSON parsers in the standard libraries, and when it's not the case, surely someone has already built a third party library. In case of Rust, JSON support comes out of the box in the serialize::json module.

Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

The state of HTTP libraries in Rust is a constant flux. See Are we web yet? for an overview of the current affairs. There's rust-http which although usable (for example Nickel builds on top of that) is not developed anymore. Teepee, it's conceptual successor, is in the words of it's author not even vaguely usable. Meanwhile a new library emerged during the last few months: hyper, which will be the subject of this blogpost.

Important note: this article is outdated! Go to http://zsiciarz.github.io/24daysofrust/ for a recent version of all of 24 days of Rust articles. The blogpost here is kept as it is for historical reasons.

One of the few chores when building a commandline program is argument parsing, so that myprogram --config=myfile.conf --verbose -o output.txt makes sense. Some arguments come in short and long variants, some are optional and some are positional only. There are a lot of libraries for argument parsing, some are even included in the respective languages' distributions. In Rust's case there's the getopts crate.

The first thing a moderately savvy user will do is... no, not read the documentation, but run myprogram -h (or --help) to discover available options. getopts and other libraries can derive such help summary for you, saving your time and reducing duplication. But what if it was the other way round? You'd write the usage message, listing possible options, and the tool would build an argument parser from that. Enter docopt.