Re: Text properties slow down XEmacs

Hrvoje> Simon, you know things about font-lock. Perhaps you'd like to Hrvoje> comment on this? We're having a discussion about whether it Hrvoje> is better to use text properties or extents for font-locking. Hrvoje> (Text properties are much slower in XEmacs than they are in Hrvoje> GNU Emacs.) Sure. IMHO, for conceptual, reasons font-lock.el should use overlays/extents. Text properties are what the phrase says---they are intrinsic to the text and so should get saved with the text. In the case of font-lock.el, we just want to change how some "text" looks to make it easier to read---because the text has meaning that is not intrinsic to the text. (When the "text" is a C program, superficially it appears that font-lock.el is right to use text properties, but I think this is misleading because font-lock.el usually gets it right.) If you like, I think the highlighting is a property of the major-mode rather than the buffer text. If you paste text from a C mode buffer into a Text mode buffer it should not take its highlighting with it. But I don't know why font-lock.el uses text properties. Perhaps it is just because they were (and still are) much easier to use than overlays/extents for the purposes of font-lock.el. I don't know why XEmacs has non-duplicable text properties. Sounds like an oxymoron. Simon.