Re: XEmacs-21.4.5 info-look; sync with Emacs-21.1

Hrvoje> "Stephen J. Turnbull" <stephen(a)xemacs.org&gt; writes: >> Hrvoje> If at all possible, it should be done with extents. Hrvoje> Except they're slow and buggy. Always have been. :-( The "buggy" I can't speak to. "Slow" is (AFAIK) a function of needing to coalesce and split extents due to deletion or addition of text lacking the property of the surrounding text. But this needs to be done, in many cases. Maybe the text properties code could be optimized a bit. But extents themselves can be extremely slow if you aren't working "in display order". They just lend themselves to caching, which is basically impossible with text properties. Hrvoje> More and more packages are using overlays, which also goes Hrvoje> to show that text properties are not as useful as Stallman Hrvoje> has made them out to be. Big surprise there. I agree with rms that they are quite useful in many situations. However, once you abstract from "text as a stream of characters" and start looking at document structure, you no longer have any way to get your hands on the text properties. And there are times when you'd like to structure a region even though it all has the same property. So they're quite useless (without kludging) for many modern applications. But you know how rms feels about "constraints" and "abstraction". -- Institute of Policy and Planning Sciences http://turnbull.sk.tsukuba.ac.jp University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN Don't ask how you can "do" free software business; ask what your business can "do for" free software.