vi/comp.editors.FAQ

Newsgroups: comp.editors,news.answers
Approved: news-answers-request@MIT.Edu
Followup-To: comp.editors
Subject: comp.editors - Frequently Asked Questions
Expires: Fri 10 Sep 92 09:07:34 1992 GMT 
Reply-To: Ruben@Uib.no

Archive-name: editor-faq/The_FAQ 



The following file is a set of Frequently Asked Questions for the group
comp.editors.  Certain questions get asked time and again, and this is
an attempt to reduce the bandwidth taken up by these posts and their
associated replies.  If you have a question, please check this file
before you post.  It may save a lot of peoples time.

This FAQ tends to ignore emacs related questions, as they tend to be
answered adequately in the comp.emacs FAQ.

Please send all comments, discussion, suggestions for new questions and
so on to me, Ove Ruben R Olsen <Ove.R.Olsen@ubb.uib.no>.  I'll try to 
answer everything I get.  I especially need more 'where to get sources'
answers.  I'd like some Anonymous UUCP sites, if at all possible.

01) What is comp.editors?
02) Where can I get the latest release of GNU emacs/elvis/crisp/joe/...?
03) Someone has just posted 'my editor is better than your editor'. What
04) Can I get hold of the source code for VI?
05) I have a Emacs question. Should I ask it in comp.editors, or in
06) Someone just mentioned the 'buffer gap method'. What do they mean?
07) How do I reformat paragraphs in vi?
08) Has anyone got a simple editor for Unix?
09) Are there any vi archive sites around?
10) Where can I get vi for VMS?
11) How do I edit binary files with VI ?
12) Why does vi sometimes tell me 'Too much macro text'?
13) Is there a list of bugs in vi?
14) Whats a folding editor?
15) Where can I get the DEC editor EDT for UNIX.


01) What is comp.editors?

Comp.editors is an INET group for the discussion of editors, editing
interfaces and internals generally.  For discussion of what an INET
group is, please see the regular postings in news.announce.newusers.
There was discussion some time back about making comp.editors into a
regular usenet group, but so far nothing has come of it.

Almost anything editor-related is acceptable in comp.editors, with a few
caveats (see question 05).


02) Where can I get the latest release of GNU emacs/elvis/crisp/joe/...?

You should check out the companion posting on this issue.


03) Someone has just posted 'my editor is better than your editor'. What
    should I do?

Ignore it.  Don't post a reply to comp.editors, whatever you do.  These
flame wars tend to go on for ages and they never change anyones mind.
If you really must reply use email, or alt.religion.emacs.


04) Can I get hold of the source code for VI?

Not without a AT&T source license.  VI is a direct descendent of ed(1),
and is therefore subject to AT&T licensing.  Even if you were to get
hold of the code, to remove all of the AT&T code would be impractical.

There are, however a lot of public domain clones of vi around, Elvis and
Stevie being two.  You may also want to check out Vile, which is a vi
feelalike, based on Microemacs.


05) I have a Emacs question. Should I ask it in comp.editors, or in
    comp.emacs/gnu.emacs.help?

If the question is specifically about an emacs variant, no.  You would
probably get more joy from one of comp.emacs or gnus.emacs.help.
Gnu.emacs.help is specifically for GNU Emacs, whereas comp.emacs
encompasses all variants of emacs (Yes, there is more than one type of
Emacs - there are over 50 in fact). 

However, If the question is about an emacs in relation to another type
of editor, then its probably ok to post it here.


06) Someone just mentioned the 'buffer gap method'. What do they mean?

An editor can hold text in memory in a number of ways. If you use the
buffer gap, the file is split into two buffers, with the cursor always
between the two buffers, ie:

[ first buffer ][ second buffer ]
                ^ cursor is here

When the cursor is moved, a character is just copied from one buffer to
the other (depending on direction). This method makes inserting &
deleting and string searching easy. Insertion just requires extending
the first buffer by one character. Deletion is just removing the last
character of the first buffer. For string searching the file can just
be treated as a single string, with care only needing to be taken when
the match straddles the gap. Disadvantages include difficulty with line
based operations, and problems with page faults when the second buffer
is large. It's also quite hard to implement properly on some segmented
architectures. This is the method used by GNU Emacs.

Another method is a linked list of lines. This is exactly what it says.
When you read in the file, you split it up into lines, maintaining
pointers to the previous & next line. Line-based functions are much
easier with this method, but searching isn't so easy.


07) How do I reformat paragraphs in vi?

Rather than write a set of macros to do this for you, it's usually
easier just to use an external program to do it for you.  If you have
fmt(1), then {!}fmt will reformat the paragraph under the cursor.  This
can be fitted into a macro easily enough.

If you don't have fmt, then you can use nroff(1) similarly (with a few
caveats about getting rid of trailing blank lines).

A format program is also to be found inside the EX/VI archives.  The
filename is vi.reformat.tar.Z.  It claims to be a WordStar reformat.


08) Has anyone got a simple editor for Unix?

This comes up a lot. The answer is usually Microemacs, or some clone of
it. Another choice might be joe, crisp or fpted. See question 02 for 
where to get them from.


09) Are there any vi archive sites around?

Ove Ruben R Olsen maintains one of the biggest vi archive sites around.
His site is mirrored at a number of sites worldwide.  See the companion
posting for more information.


10) Where can I get vi for VMS?

Both TPU and GNU Emacs have vi emulations.  You can generally find them
in ftp archives.


11) How do I edit binary files with VI ?

To do this you need a program that converts you binary file to
a plain ascii file. In the EX/VI archives there are two programs
to do this:

vi.bed.tar.Z     - A good frontend.
vi.bined.tar.Z   - Two filters to convert binary files to/from ascii.
                   Claims to solve the "Line to long" message.


12) Why does vi sometimes tell me 'Too much macro text'?

When vi starts up, it looks in three places for initialisation commands
of some description.  It first looks in your EXINIT environmental
variable.  If it doesn't find that, then it looks in the current
directory for a file called .exrc (some vi's do this *as well as*
looking at EXINIT anyway), and sources that instead.  If it doesn't find
either of these, then it sources $HOME/.exrc.

The problem is that some vi's source both .exrc files anyway (this is
wrong - it should only ever source one), and vi's buffers overflow
giving you the above error message.  One more bug found, Mr. Joy.


13) Is there a list of bugs in vi?

Not at the minute.  If anyone would like to collect a list of known
bugs, I'd be happy to post it with this FAQ.


14) Whats a folding editor?

Another word for 'folding editor' is 'outline editor'.

This is quite a hard concept to explain without having a folding editor
in front of you to explain with.  The idea behind it is to hide text
behind some sort of descriptive heading.  For instance, if you were
working on some C code, but didn't want to see the millions of C
headers, you could fold that text away behind the heading 'INCLUDE FILES',
like:

In a normal text editor, the file would look like:
--- begin ---
#include <stdio.h>
#include <stdlib.h>
#include <bar/foo/blrufl.h>
#include <ktb/kick/inside.h>
#include <mary/had/a/little/lamb.h>

int heights()
{
	return wuthering();
}
--- end ---

in a folding editor, it might look something like this:

--- begin ---
... INCLUDE FILES

int heights()
{
	return wuthering();
}
--- end ---

Of course, the line can be unfolded, and you can see the original text,
and in editors such as Origami, this folding can be nested.



15) Where can I get the DEC editor EDT for UNIX.

  [ Information supplied by Castor Fu (castor@drizzle.stanford.edu) ]

  1. Using the the GNU Emacs EDT emulator. 
     This provides you with the key bindings but doesn't really have 
     the look and feel.  One of the nicest things about EDT for novices 
     is that it really controls a vtxxx terminal competently, and makes 
     use of highlighting, keypad, etc. to aid casual users.  This 
     implementation is designed for the "expert" edt user who has no 
     need for such niceties and primarily wants the key bindings for 
     his keypad.

  2. Buy a commercial product.  Probably the most widely used such is 
     EDT+ from:

     Boston Business Computing
     3 Dundee Park,
     Andover, MA 01810
     USA
     +1 508 470-0444, FAX +1 508 474-8244.

     I used their product a little bit on a Multiflow, but not enough to 
     REALLY tell how good it is. 
     Their product will probably cost somewhere $500 and $1000. But it 
     really looks like EDT to me.

  3. Wait for DEC to announce it's port of TPU to Ultrix? I heard they 
     intend to make this a product.  

  4. We've started using Anker Berg-Sonne's SEDT. It's become the editor 
     of choice in our group among those who don't already know vi or 
     emacs, because it's very easy to use.  I don't know why, but it is 
     not widely used/known about in the unix world for some reason. 
     (See also question 2 for where to find this editor).