From: utzoo!decvax!ucbvax!ARPAVAX:C70:editor-people Newsgroups: fa.editor-p Title: Re: buffer structures Article-I.D.: ucb.1970 Posted: Mon Sep 20 01:57:00 1982 Received: Tue Sep 21 05:48:36 1982 >From z@CCA-UNIX Mon Sep 20 01:54:22 1982 CCA EMACS uses an array of line pointers rather than a linked list of lines; in such a scheme I don't see any problem in implementing buffer bounds or in efficiently determining which of two buffer positions is "first". Actually, the only reason I haven't implemented buffer bounds in CCA EMACS is that they're somewhat low in priority; they are definitely on my list to be done, though, and their implementation is straightforward. If they had been designed-in from the start, they would have been quite trivial to put in. However, I started out with Montgomery's EMACS and have had to retrofit a lot of stuff. The same goes for nondrifting marks; this is also a feature which has recently been installed. To determine the relative positions of two points may take two comparisons in a line-oriented editor compared to one in a buffer gap editor, but in terms of actual peformance this difference is insignificant. In actual execution, only one comparison is usually needed anyway. All in all, I am quite happy with the line oriented approach, and I think it is a major reason why command execution speed in CCA EMACS is generally quite fast. Steve Zimmerman