Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84 SMI; site sun.uucp
Path: utzoo!linus!decvax!decwrl!sun!guy
From: guy@sun.uucp (Guy Harris)
Newsgroups: net.emacs
Subject: Re: 79-character screen
Message-ID: <2857@sun.uucp>
Date: Sat, 5-Oct-85 19:04:44 EDT
Article-I.D.: sun.2857
Posted: Sat Oct  5 19:04:44 1985
Date-Received: Mon, 7-Oct-85 07:16:04 EDT
References: <70@druhi.UUCP> <227@epicen.UUCP>
Organization: Sun Microsystems, Inc.
Lines: 28

> >When using Gosling's emacs, i notice that column 80 never gets used.  When
> >i have long lines, the last character displayed is in column 78, and column
> >79 has the '\' or '$' in it. 
> 
> I suspect you have a VT-100 compatible terminal. On many of these terminals,
> wrapping when reaching the end of line is broken; the cursor wraps but the
> last typed character doesn't, or vice versa.

It is arguable that the VT100 method for handling column 80 is *better* than
the normal method.  On normal terminals with end-of-line wrap, if you put
something in column 80 the cursor goes to column 1 of the next line; if the
cursor is already on the last line the screen scrolls up to accomodate this
move.  This means that a full-screen program *cannot* use column 80 on the
bottom line of the screen, or at least has to do an annoying amount of
repair to clean up after that scroll.  If you put a character in column 80
on a VT100, and end-of-line wrap is enabled, the cursor's motion to line N+1
column 80 is deferred until the next character is to be displayed.

The trouble with this is that some display code isn't prepared to handle
this, and that it's not clear where the cursor "really" is under these
circumstances.  On the VT100, you can turn end-of-line wrap off, which is a
more reasonable mode for all full-screen programs except those (like "vi"
and EMACS) which handle wide lines by wrapping them rather than by having a
window into the text which can be shifted horizontally (I did a screen
editor which had such a shiftable window, and prefer it to the "vi"/EMACS
style of wrapping).

	Guy Harris