mark (03/04/83)
Where would you put the cursor when at the end of such a line?
You could do what vi does - put the cursor at the beginning of the next
line, without doing the insert line unless an 81st character is typed.
This is ambiguous but I've never seen anybody complain about it in vi,
it never seems to cause any confusion.
James has solved the "does this terminal have automatic margins" problem
by just not using the last column. It turns out that, as long as you don't
use the last column of the bottom line (because that can cause scrolling),
there are no real problems with using all 80 (or whatever) columns. You
do have to know which of three kinds of terminals you have:
(1) automatic margin: cursor goes to next row, first column.
(2) non-auto margin: cursor hammers on right margin (stays put)
(3) eat-newline: (vt100 and concept) terminal goes into weird state so that
if crlf follows, it eats the automatic margin, otherwise it generates one.
This is handled by outputting an extra crlf after the 80th char.
This info is present in termcap and terminfo, so EMACS should have no trouble
accessing it. However, note that even if you only write characters in the
first 79 columns, there is no problem with putting the cursor in column 80,
solving the first problem above. Also note that, for all practical purposes,
a text editor user won't care whether there are 78 or 80 columns available,
unless editing card images or some screen layout that is 80 columns wide.dean (03/04/83)
From: Mike.Dean My big complaint about how Gosling's emacs handles long lines is with regard to its redisplay logic. When inserting characters into a line, the redisplay correctly uses the insert mode of my terminal (a heath19) until it begins to wrap around. At this point, it starts repainting each of the characters until it gets to the last "continuation line". On a dialup this can get quite annoying. Mike Dean rochester!dean
thomas (03/08/83)
I have a fix to TrmTERM.c which does a better job of calculating the costs involved in insert and delete character than the kludge in the distributed version. I can send this to people who are interested (or maybe post, if there is enough interest). Anybody who got my changes package already has it. =Spencer
jdd (03/08/83)
And then, you could be really clever and split 80-character lines only when
the cursor follows the last character (not too often).
Cheers,
John ("Control-Meta-Shift-Cokebottle") DeTreville
Bell Labs, Murray Hill