A number of programming languages offer a feature called “Named Arguments” or “Labeled Arguments”, which makes some function calls much more readable and safer. Let’s see how hard it would be to add these in Rust.

Years ago, Andrew Kennedy published a foundational paper about a type checker for units of measure, and later implemented it for F#. To this day, F# is the only mainstream programming language which provides first class support to make sure that you will not accidentally confuse meters and feet, euros and dollars, but that you can still convert between watts·hours and joules. I decided to see whether this could be implemented in and for Rust. The answer is not only yes, but it was fun :)

Credit While I’m the author of this blog post, 99% of the work was done by Nicolas B. Pierron. So far, my role in this project has largely been to play the wise old advisor, nodding and smiling mischeviously whenever Nicolas started exploring new ideas, and emitting cryptic comments in Reverse Jedi Notation. A few months ago, we published a short (and mysterious) blog post in which we mentioned HolyJIT, an early research project towards a novel approach to writing JITs. In this blog post, I would like to detail a bit more the ideas behind HolyJIT.

A long time ago, the Rust language was a language with typestate. Officially, typestates were dropped long before Rust 1.0. In this entry, I’ll get you in on the worst kept secret of the Rust community: Rust still has typestates.