Racer is a code completion tool for the Rust programming language. Time for another progress update!
1. Cargo support
The big news is that I recently added some cargo support to racer:
When searching for crates racer now interrogates the nearest Cargo.lock and Cargo.toml file and then searches git checkouts and crates.io repos in the ~/.cargo directory. This was a bit fiddly but luckily I had the source-code to Daniel Trstenjak's excellent rusty-tags project to refer to. Thanks very much Daniel!
2. Rust Beta
Racer relies on some unstable libraries at the moment, which unfortunately means it won't currently build with the Rust Beta channel. Hopefully this situation will be remedied over the next few weeks before 1.0, but in the meantime you need a rust nightly install to build racer.
(Unstable features used are: collections, core, rustc_private, str_char, path_ext, exit_status. Patches very welcome!)
3. Performance improvements
Back in February Renato Zannon noticed that racer was spending a lot of time spawning threads. The spawning was originally designed to protect against libsyntax panics, and preventing crashes has become an important issue recently because there is a lot of demand to provide racer as a library for linking with IDEs. Unfortunately the thread spawning also generates a lot of overhead and removing it more than doubled the performance of racer in a lot of cases.
The thread spawning is currently removed from the codebase, which means that racer will sometimes panic and fail to produce matches. As an alternative to wrapping libsyntax calls I've been spending time removing panics from Rust's libsyntax itself in the last few weeks. If you want to follow along the PR-in-progress is here.
4. Type Inference
Not much progress on the type inference front I'm afraid. I'm now more convinced than ever that racer should be using rustc for type inference rather than continuing to roll its own. The question is how to get there: the rust compiler is currently not the right shape to do incremental type inference. There is plenty of desire in the community to have a compiler library that can support IDEs, so I plan to help out there where I can.
As a start I'm going to try having racer construct small representative pieces of code to compile (in the same way as it does with using libsyntax to parse), and see where that takes me.
Once again, a big thanks to all the Racer contributors. Your help and support is much appreciated:
Andrew Andkjar, awdavies, Ben Batha, Björn Steinbrink, Björn Zeutzheim, Dabo Ross, Darin Morrison, Derek Chiang (Enchi Jiang), Emil Lauridsen, Henrik Johansson, Heorhi Valakhanovich, Jake Kerr, Johann Tuffe, Jorge Aparicio, Justin Harper, Keiichiro Ui, krzat, Leonids Maslovs, Marvel Mathew, mathieu _alkama_ m, Michael Gehring, Michael Maurizi, nlordell, oakes, Pyry Kontio, Renato Zannon, rsw0x, Saurabh Rawat, Sebastian Thiel, Siddharth Bhat, Vincent Huang, Vlad Svoka, Zbigniew Siciarz, Ziad Hatahet.