From: utzoo!decvax!ucbvax!ARPAVAX:C70:editor-people
Newsgroups: fa.editor-p
Title: buffer structures
Article-I.D.: ucb.1971
Posted: Mon Sep 20 02:44:37 1982
Received: Tue Sep 21 05:50:57 1982

>From GZ@MIT-MC Mon Sep 20 02:42:30 1982
I don't see what the difficulty is with implementing virtual bounds
in the linked list of lines scheme.  If you mean the fact that the break
can occur in the middle of the line, well, you split the line at the given
point, and merge it back when lifting the bounds. Of course you unlink the
out-of-bounds parts and keep 'em somewhere else, so the problem of verifying
relative positions only comes up when you are changing bounds, not all the
time.  Implementing virtual bounds would be no worse than any region operation.

I do agree though that the problem of comparing positions is one of the
major disadvantages of the linked list approach, making all region hacking
more expensive.

Also, a correction: Gosling's emacs uses the buffer+gap scheme.