I have just gone through the always-slightly-worrying process of submitting a new version of fontspec to CTAN. (There’s always more typos and bugs you wish you could fix before you hit that “Upload” button.)
The new version is a major release, v2.0, representing quite a significant internal update over the v1.18 release that’s been going strong since, well, ages. There are quite a few minor problems that have been squashed (especially related to various combinations of font-loading features), and the code has been simplified and improved in several areas. In particular, it now uses the expl3 programming language, which I’ve been working on with the LaTeX3 project. It’s not a complete port, however, so the package code is currently a big mish-mash of TeX, LaTeX, expl3, and, yes, Lua code. Don’t look at the sources unless you’ve got a strong constitution.
Unfortunately, the new v2.0 release has not been targeted towards fixing all the bugs nor adding the features that have been requested and discussed. (Interested parties should visit the Issue Tracker for more information.)
So while some things have been fixed in the process of re-writing and generalising (some of) the code, I haven’t managed to look at everything. In particular, the documentation is in a significant state of disrepair. There aren’t even any typeset examples, which I’m not too happy about. But they’ll come.
The reason fontspec has been released now, specifically, is because TeX Live 2010 has just gone into testing. Thanks to the efforts of Khaled Hosny, Elie Roux, and Manuel Pégourié-Gonnard, fontspec is now fully functional with the LuaTeX engine, which is slated to become the de facto TeX engine in a few years time. Being able to easily select fonts and OpenType features is a big step toward promoting LuaLaTeX (as it’s called) for more general use.
The new version of fontspec should still be fully functional in XeTeX running on TeX Live 2009. There has not been a huge amount of testing for the new release; I’d greatly appreciate any and all XeTeX users reading this to try out the new package as soon as possible and report problems back to me.
LuaTeX users, however, require some significant updates before fontspec will work for them (involving luaotfload and post-TeX Live 2009 LuaTeX binaries, specifically). I recommend waiting for a refreshed testing version of TeX Live 2010 before trying out fontspec with LuaTeX. I’ll be writing about some of the changes we’ve made for LuaTeX users in the future.
While TeX Live 2010 is in testing, I’ve given fontspec v2.0 the designation of “b1” to indicate it’s still under development. I hope (ha!) that few changes will be required to the code while we’re testing and the beta status can be dropped before TeX Live 2010 is completed. After all that I’ll try and fix up the documentation.
In the meantime, I’m also planning to finally release my unicode-math package as well. Stay tuned.