What Is It
RX is a pure-Ruby XML parser written by Tim Bray, in an effort to make an alternative to REXML.
The code is largely unchanged from when Tim wrote it several years ago. I (@headius) have made a few small optimizations.
Currently, the benchmark (test/bench.rb) indicates that on JRuby, RX runs about 10% slower than REXML for parsing a large XML file On Ruby 1.9.2, the ratio is above 2x.
I post this mostly to see if there's interest in getting a better pure-Ruby XML parser alternative to the much-maligned, inaccurate, buggy REXML currently shipped in Ruby's standard library.
Getting performance on par with REXML is the first priority. If we can't make a real parser (i.e. one that will actually reject bad XML) that matches REXML's performance (heavily Regexp-driven), then there's no chance. I believe we can.
Once it looks like performance can match REXML, we would want to fill out remaining functionality and perhaps try to match REXML's user-facing APIs.
Commit rights will be given freely to anyone who wants to work on this.
Tim says: I have some cycles. I'm sort of out of ideas on how-to-make-it-run-fast, but if someone can break through that logjam, I'd commit to maintaining the automaton DSL and actual XML-specific code; even adding proper entity support (yecch). And XPath support.