Broff and a proposed net project

[Guy Harris]

	Layout (formatting), and text entry have traditionally been separated.
	While not all traditions are worth carrying forward, there usually is
	some reason for their existence in the first place: Text entry must be
	highly interactive and responsive, while text formatting must be very
	powerful and flexible. The computer power it takes to provide the
	flexibility and power for formatting is much greater than that required
	by, say, emacs. Due to this imbalence, putting formatting functions in
	an editor frequently causes the editor to become unacceptably slow.
	Also, formatting and text entry have two separate goals. Text entry
	provides content, formatting provides form.

Well, for fancy layout problems, like books, you might be right.  For less
demanding tasks, like letters, memos, technical documentation, etc. - well,
let's just say Wang probably sells more of their word processing equipment
(with an editor/formatter) in a month than text-editor-plus-nroff systems
are sold as word processing systems in a year.

Also, the claim that two functions are "logically separate" may not mean that
they should be done by two separate programs.  How many times have we all
gone through a cycle of edit-nroff-proofread-edit-nroff-..., not to correct
typos, spelling errors, and other semantic errors but just to correct the FORM
of the underlying document?  In addition, dealing with a separate editor and
formatter involves a process of abstraction that can make the work more dif-
ficult and which doesn't necessarily serve any purpose.

But I think the prime argument is still the "fifty million Frenchmen can't
be wrong" one.  Yes, there are people who argue that tube amplifiers are better
than transistor ones, but given the sales figures I think the battle has been
won.  The benefits conveyed by transistor amplifiers outweigh those conveyed
by tube amplifiers for the vast majority of buyers.  The same is true for
editor/formatters and separate editor/formatter packages; all the commercial
text editing systems sold for office use, except for a specialized few, are
editor/formatters.  The Seybold Report on Office Systems has repeatedly
criticized systems with separate editors and formatters, and said that those
systems would never catch on; they were and are right.  I can do just about
anything with our editor/formatter that you can with "nroff", and more easily
and better to boot.

As for the claim about CPU resources used by an editor/formatter and "emacs";
I'd have to see "emacs" in action before I believed that.  I've been told that
"emacs" requires more CPU resources than "vi", and "vi" has on occasion looked
competitive with our editor/formatter.  It's all in how you implement it.
There are several commercial word processing systems that use Z80s as their
main CPU, so obviously it's not an impossible task to make it efficient.

	Most of the people involved in this discussion are familiar with
	powerful text editors, but many of us are quite unaware of how much
	effort goes into laying out a book or newspaper with a computerized
	layout system. Further, computer layout systems are undergoing a
	revolution in functionality and expressive power. And we are just
	beginning to understand how to represent the graphic information that is
	typically found on the printed page.

	For these reasons I don't expect to see an editor that combines layout
	functions with text entry. An interactive layout program, even a slow
	one, that allows graphics to be mreged with text, pictures to be
	halftone-screened, and page layout to be easily manipulated would be
	well worth hacking.

Well, go down to your nearest Xerox Office Systems Division sales office and
ask to see a demo of the "8010 Information System".  You may know of it as
the "Star".  Yes, it's slow, BUT - it includes an interactive editor/formatter
which understands:

	multiple fonts
	multiple type sizes
	graphics within text
	multi-column text
	page layouts
	mathematical formulae
	tables

and does much, although not all, of the formatting as you type.  I agree that
dynamic as-you-type PAGE composition is probably very difficult and may not
be desirable to implement.  And if you want a paragraph formatting algorithm
like Knuth's, where a small change to one line can affect lines above it as
well as below it, you may not want to implement it within an editor/formatter
(or not be able to).  And it may not be possible to do book, newspaper, or
magazine layout with such a system.  HOWEVER, for most relatively simple layout
problems, such as one-column text, two-column text of the type done by the
"-ms" macro package, and the other sorts of things asked for by letters,
technical documentation, technical papers, reports, memoranda, and the like,
the battle has already been fought and won - by the editor/formatters.  In
those cases, there is no good case for separate editors and formatters.  We
know enough now about how to do editor/formatters that the benefits of
separating the editor and formatter have disappeared.

	Guy Harris
	{seismo,mcnc,we13,brl-bmd,allegra}!rlgvax!guy