rst 0.3 released, now with a web ui and windows, linux and mac osx binaries!

I have just released the 0.3beta release of rst, the requirements tracking tool made for developers. This release brings many benefits, including support for all major platforms and a web-ui for viewing requirements. In addition, I have a clear path forward for how to make the web-ui be able to edit the requirements as well.

There are many points I would like to cover in this post, in summary they are:

  • rst’s licensing changes
  • learning a new programing langugage to write the front end in, elm
  • using and the jsonrpc_core rust libraries for the backend
  • packaging the static html files directly into the released rust binary

rst’s primary goal is to be simple – to make it easy to track requirements and integrate into development tools. It will always run locally on your machine

Change to a copy-left license

Just before the 0.3 release I switched rst’s license from the MIT permissive license to the LGPLv3+ copy-left license and I would like to talk a little bit about why.

rst is an application tool that I strongly feel developers need. Requirements tracking and detailed design are core pillars to effective software development, and yet there are really no tools to express these ideas that improve a developer’s day to day work. In summary, there is nothing like git for requirements tracking.

But there should be! What are requirements but a name, a piece of text and links to other requirements? This is a simple problem with a simple solution, but the industry has not pursued simplicity – all we’ve gotten is large web tools with database backends.

By having your requirements be simple text files that live in your code, you get another benefit – the requirements can easily link to your code and be revision controlled with your code. This allows you to integrate your requirements with tools you already use for tracking your code development (github, Atlassian, etc).

Because rst’s very design is to enable simplicity, it was important to me that the core library always remain open source. That is why I chose LGPL, it allows propriety companies to use rst as a library and build on it, but if they want new features then they need to share. Free developer tools should remain free and companies that want to improve them should contribute.

On the other hand, I fully support using rst within a larger application, and that is why I am using the “Lesser” GPL which allows others to build on rst and why the format for the artifact files are public domain.

Learning Elm

The rst backend and cmd line tool are written in rust a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety. There really is no replacing rust – it is an amazing language for the backend. The safety guarantees make runtime errors practically impossible.

Elm is a functional programming language designed from the ground up to make WebUIs that are maintainable and fun to program. I have to say they accomplished all those goals, and learning elm after learning rust was pretty much a matter of just learning new syntax. Many of the concepts that rust taught such as expressions returning a value and pattern matching were utilized for exactly the same benefit in elm.

A frontend in elm with a backend in rust is a match made in heaven: fun, performant and safe.

Rust web development

Before I got too far, I would like to give a shoutout to and jsonrpc_core. They made developing a json-rpc backend about as easy as anyone could ask for.

What was really fun was learning how to package an elm/node app into a rust binary – it turned out to be surprisingly easy! I used just to create a simple makefile which compiles my node/elm frontend into a tar file that I included in the source. I then then use the include_bytes! macro to include the tar file directly in the rust binary during the build. I then followed the directions on rust-everywhere to compile rust for linux, mac and windows. It was a pain figuring out how to package the node-app in a cross platform manner, but other than that it went really smoothly!

With nickel, hosting was as simple as server.utilize(StaticFilesHandler::new(&tmp_dir)), where tmp_dir was just the unpacked tarfile in a temporary directory created by tempdir. Big shoutout to alexcrichton, along with your toml library I have used an incredible number of your tools for core development needs – you have done an incredible amount to make rust useful for developing complex applications!

If you want more details, check out the source code at


Huge steps have been made in the development of rst, with a read-only web-ui deployed, and a fully supported one which includes editing just around the corner. I simply cannot be thankful enough to the wonderful people who have made rust and elm what they are today. These languages make development easy and fun, and anything that I can do to support them I will do.