I’m at the Blogging-from-TextMate party, too!
This entry written in, and posted from, Mac OS X über-text editor TextMate, using Brad Choate’s Blogging bundle.
I’ve been aiming for this high-five moment for a couple of weeks, but I kept getting http-proxy-related (I think) Ruby errors when I tried any network activity. I’m not sure why it’s suddenly working now. Probably a fix in the constantly updated cornucopia of text-editing goodness that is the TextMate bundles repository. Part of the problem was the little RPC bug Horst identified, and part was messed-up passwords in my keychain.
(Not quite ready for Textpattern; I had to manually set the intended section from the browser interface because I can’t find a workable syntax to specify which Textpattern section to use. Textpattern’s “sections” are analogous to other tools’ “blogs.”)
Thanks, Brad, Allan, and others, for these exciting tools.
Update: Cool, now there’s a Blogging bundle troubleshooting page.

