fast_blank

I guess that was the key takeaway from your talk: Ignore local optimisations in favour of more global ones. The fact that you parse C extensions was really unexpected. Given something like Object#blank? using the Ruby implementation vs Sam Saffron's "fast_blank", after JRuby+Truffle has done it's work, which implementation ends up more performant? And would a future JRuby+Truffle (given both the Ruby and C implementation) make an intelligent decision of which one to use? https://github.com/SamSaffron/fast_blank

> Rust can use simd too. No it can't. Either accept that the nightly build of Rust is not the Rust we are talking about or stop discussing with me. > Re:regex: my point exactly. The problem with regex libraries are that they are to big so therefore doesn't reveal so much about inherent language performance. > Most microbenchmarks are prone to slight differences in the implementation causing issues (and you can rarely translate code exactly, especially to something like rust which often requires a different structure of code from C. Same for any two other langauges). Yes, obviously the implementation defines performance. That's what I wrote in the other thread part: "this discussion is about Rust vs C. Or rather clang 3.6.2/gcc 5.2.1 vs Rust 1.9.0 since language performance is very implementation dependent" And fwiw, you can easily transli

For those not interested in watching a long video: The C code: https://github.com/SamSaffron/fast_blank/blob/master/ext/fas... The Rust code which is slightly faster: https://gist.github.com/robinsonstrategy/794164e992bec9ca9b8...

If you don't want to invest in a two-hour long video: TL;DR: Rails has a library, `ActiveSupport`, which adds methods to Ruby core classes. One of those methods is `String#blank?`, which returns a boolean (sometimes I miss this convention in Rust, the `?`) if the whole string is whitespace or not. It looks like this: https://github.com/rails/rails/blob/b3eac823006eb6a346f88793... It's pretty slow. So Discourse (which you may know from {users,internals}.rust-lang.org) uses the [`fast_blank`](https://rubygems.org/gems/fast_blank) gem, which provides this method via a C implementation instead. It looks like this: https://github.com/SamSaffron/fast_blank/blob/master/ext/fas... For fun, Yehuda tried to re-write `fast_blank` in Rust. Which looks like this: extern crate libc; mod buf; // a small buffer struct + impl, not shown use bu