Back in Rust 0.5, there wasn't a lot of documentation for Rust. I wrote down information as I learned the language, and put together this introduction to the language. read online for free or download a PDF, MOBI, or EPUB.
Yup! I wanted to pay for the cost of hosting. But now, I'm releasing it for free, 100%. You can donate me $5 if you want to, though.
I have recently started a contract to re-write the official Rust tutorial, and so, don't plan on putting significant future effort into Rust for Rubyists. It'd just be the new official tutorial anyway! You can check out my work in progress here and here.
Well, they're not done yet.
I update for each release. The current release is 0.11. Many people use Rust nightly, however, so some details have probably changed between now and then.