🚀 go-pugleaf

Emacs predates vi, so if either program is guilty of incompatibility, it is
the latter. 

Secondly, there is no correct definition of "scroll up" or "scroll down",
because the direction of scrolling depends on your frame of reference.
There's no particular reason to choose one frame of reference over another;
some people find one more intuitive, others another.

>THEY SCROLL UP/DOWN IN DIFFERENT DIRECTION!

1) Imagine that in emacs you are scrolling a typewriter (you know, the
   kind with platens and all).  You turn the platen upwards to move
   to lower parts of the page, etc.  Remember, emacs was written
   back before wordprocessors and window systems were common items.

2) Does it matter?  Normally you would use the key rather than
   typing in scroll-up.  By the time you learn enough to type
   the whole command in, you should be well versed in how it
   works.  Note:  The function is normally bound to the key
   Control-V, and V is a downwards pointing letter!

3) What is "intuitively" the best way varies from person to
   person, and is useless as an argument.  Perhaps intuitively
   cars should always drive on the right side of the road?

4) Who CARES if things are different?  Do you want the computer
   police wandering around everywhere to make sure all programs
   behave the same?  If so, go tell it to your apple marketeer.

5) Are you really confused, or trying to raise an irrelevant
   question in your fight to show that emacs is substandard?
-- 
Darin Johnson
djohnson@ucsd.edu  --  Toy cows in Africa

In article <SHIBUYA.93Jan7195820@chute.bl.applicon.slb.com> shibuya@bl.applicon.slb.com writes:
>I just came across a fundamental difference between Emacs and VI,
>which I never noticed for a decade.  
>
>THEY SCROLL UP/DOWN IN DIFFERENT DIRECTION!
>
>Emacs command "scroll-up" scroll the text up so you see the text
>further down.  VI command ^U, is described in the manual as "scroll
>up", which scroll the text down so you see the text further up.
>
>What bothers me is that my dear Emacs acted the different way I
>thought it would.  I always thought scrolling down is going toward the
>end of document.  I never bothered to lookup which command was doing
>which. (well, who does M-x scroll-down/up to scroll?)  This is a big
>blow in my religous belief.
>

Well, to be a purist about it, think about the actual analogy to a
papyrus scroll, with the rods above and below the screen.  When you
move to the end of the document, the papyrus is moving up, right?
Thus, by analogy, scrolling a document up means going to the end.

If you're reading a long scroll, you're going to move the
paper/papyrus, not your head, right?  Scrolling _down_ to the end
implies that the _reader_ is moving.  More blasphemy from the vi camp.

>If it turns out that VI is the only one goes the opposite direction,
>then it will help me regain my religious faith, and shake off my vi
>loving neighbor who is bothering me on this.  

Tell your neighbor to invest in a scroll and see which way _he_ moves
the paper.  Unless vi priests also force their supplicants to _write_
upside-down... 

--
Tim Lesher <lesher@bucknell.edu>

I can't believe all these people coming out in defense of emacs's
screwy scroll-up/down nomenclature.
I am a big fan of emacs, and yes, I've read the excuses given in the
elisp manual for why they're named the way they are...
but it's so darn counter-intuitive to me, I just can't believe that
all you people are really being honest when you say things like:

In article <FRIEDMAN.93Jan8021040@nutrimat.gnu.ai.mit.edu> friedman@gnu.ai.mit.edu (Noah Friedman) writes:
> Secondly, there is no correct definition of "scroll up" or "scroll down",
> because the direction of scrolling depends on your frame of reference.
> There's no particular reason to choose one frame of reference over another;
> some people find one more intuitive, others another.

There's GOT to be a reason to choose one frame of reference over another.
(If there isn't, then you've got to admit vi is at least as right as
emacs.)
[The above GOT is meant to express my personal frustration, not a logical
necessity...]

   Ok, here's a good reason for preferring vi's way over emacs's: when
you're in a scrolled window in a GUI and you click on the down-arrow
in the scrollbar, what happens?  You move down through the document!
The same if you drag the block in the middle of the scrollbar
downward.  Do any of you think this is ambiguous or counter-intuitive?
How about the PageUp/PageDown keys on many keyboards?  How about the
up-arrow key -- what word-processor ever used it in any way to do
what scroll-up does?  Would you expect Shift-UpArrow to move to the
beginning of the document, or the end?

   It seems to me that there's a very strong convention of moving
"down" meaning moving to a later part in the text; i.e. the observer
is moving, not the text.

Ok, how's this for an "origin of intuition" about this subject.

   In our day-to-day experience, when we want to look at a different
part of something, do we more often move relative to that thing, or
move that thing?  I say we move ourselves, or at least move our eyes
(frames of observation) much more often than we move the thing.
Looking through a telescope or binoculars.  Movies, TV.

    When reading a book, sure we turn pages, but when reading a page
(and reading a text file in emacs is like reading a single page -- or
many pages attached top-to-bottom) we move our eyes down the page.
Have you ever seen someone stare at one spot (fixed relative to their
head) and move the book upward as they read each page?  Ok, I'm being
a bit silly but on with the point.

    The only counter-examples are when we have a piece of
observational equipment that's large and hard to move compared to the
subject, such as a microscope or microfiche reader.  (Please, no
cracks about Emacs's size. ;^) This happens rarely and is
counter-intuitive.  Remember the first time you used one of these
devices?  Didn't you, at first, mistakenly move the slide or
microfiche in the opposite direction from the way you wanted to?  I
know I did... am I crazy?  Of course after a couple of seconds you got
used to it.  But we're talking about what's *intuitive* here.

   Obviously, on the surface, when we scroll through a file in emacs,
the graphic depiction of the window is standing still on the monitor
(and visually, the text moves, relative to the monitor).  But that
doesn't mean the window isn't moving; it just means that the window,
the monitor, and the user aren't moving relative to each other.
   On the conceptual level, the text is an object in an abstract space.
It still exists even when we save it in a file and leave emacs,
destroying the window.  The window exists to observe the text; the
text does not exist for the sake of the window.  Moving the text
around in this space doesn't make sense... it's irrelevant.  It has
no effect (going on the assumption that the text exists independent
of the window, and not vice versa.)  Our purpose is not to change the
location of the text; we just want to see different parts of it.
   Consider what happens when we view the same buffer in two different
windows, and we scroll one of them.  The text can't be moving, because
if it were, it would appear to move in both windows.  (Or would you
argue that scroll-up means "Move text and all other windows showing
this buffer up" ??!)  There is one buffer, and one of the windows is
moving relative to it.

   Finally -- and this would be the strongest point for any diehard
relativist who's still not convinced that it's the window that's
moving and not the text -- note that other commands for moving around
in the text are named as, well, just that: ways of moving around in
the text, not moving the text around.  It is confusing to make the
names of most commands refer to how the frame moves, but make the
names of a couple of commands refer to how the text moves -- *even if*
the latter paradigm were just as intuitive.

   For example, beginning-of-buffer moves the frame to the beginning
of the buffer.  In isearch-forward, you
  "Type ESC to exit, leaving point at location found."
See, the point is moved to a location in the text.  And our frame
follows the point.  forward-char, next-line, forward-word, forward-sexp,
end-of-line, etc. all refer to how the point moves, not to how the text moves.
(The words "up" and "down" are not the issue here -- the issue is whether
it is the text or the frame that is moving.)
Documentation string for set-window-point:
"Make point value in WINDOW be at position POS in WINDOW's buffer."
Not:
"Make point value in WINDOW's buffer be at position POS relative to WINDOW."

Why should moving the point be labelled opposite to moving the window?
They're analogous concepts.  The window surrounds the point.  The window
shows a large region of the text; the point indicates a single position
in the text.
   Usually when I hit down-arrow, the cursor goes down a line,
relative to both the text and the monitor.  When the cursor is at the
bottom of the screen and I hit down-arrow, the cursor moves down and --
why should I suddenly switch paradigms and say no, the cursor says still
but the text moves up?

In fairness to the writers of emacs, let me quote from the elisp manual:
>    Some people have urged that the opposite convention be used: they
> imagine that the window moves over text that remains in place.  Then
> "down" commands would take you to the end of the buffer.  This view
> is more consistent with the actual relationship between windows and
> the text in the buffer, but it is less like what the user sees.  The
> position of a window on the terminal does not move, and short
> scrolling commands clearly move the text up or down on the screen. 
> We have chosen names that fit the user's point of view.

I argue that the user's intuition is not as shallow as how dots are moving
on the screen.  Intuition deals with objects and their relationships,
whether seen or implied.

To put it all in perspective...
I'm not obsessed with this issue.  (Really... it's just late at night!)
I'm not lobbying for emacs to be changed.  I'm certainly not claiming
that emacs is inferior -- it's one of my favorite programs of all time.
(And that's why I care.)
I just think that for the sake of intuitiveness and consistency,
the names scroll-up and scroll-down should have been chosen the other
way.
I'm not demanding that you all agree with me either.  But I hope I've
communicated *why* I think there are very definite reasons for preferring
one frame of reference over another.

Lars Huttar                          3
huttar@hp750.itg.ti.com      ||   _______           ____      ||
(Opinions herein are not     ||:  |  |  |   |   |   |  |   | :||  Mars
necessarily those of TI.)    ||  _| _| _|  _|  _|  _| _|  _|  ||

>There's GOT to be a reason to choose one frame of reference over another.

Well, what if one reference uses "scroll" and the other uses another
word?  For "scroll-up" I imagine the text moving upwards on the screen,
as if it were being scrolled by (ala player piano, etc).
Now if it were "page-up" I would not find it hard to imaging a different
thing happening, such as the window into the text moving up.

>   Ok, here's a good reason for preferring vi's way over emacs's: when
>you're in a scrolled window in a GUI and you click on the down-arrow
>in the scrollbar, what happens?  You move down through the document!

Hmm, I bet you're still in your twenties :-)  Imagine using a GUI
as an analogy for something!  (I've only been 30 for a month, and
I'm still boggled)  The people that wrote emacs didn't have GUI's
as a reference, and very few other screen editors to steal ideas
from.  "Scroll-up" was a very appropriate analogy back then.

>The same if you drag the block in the middle of the scrollbar
>downward.  Do any of you think this is ambiguous or counter-intuitive?

*Only* because I have used scroll bars in their common setup for
so long, *not* because it is a natural way of doing things.  (ie,
when the bar moves up and down, is the window moving over the text,
or the text moving under the window?)  Since the window does not
*look* likes it's moving, it would seem natural to imagine that
the text underneath is moving (and moving the text UP gets you
closer to the bottom of the text).

>How about the PageUp/PageDown keys on many keyboards?

"Page" is not the same as "scroll" - and I think that's 99% of the
confusion.

>How about the
>up-arrow key -- what word-processor ever used it in any way to do
>what scroll-up does?  Would you expect Shift-UpArrow to move to the
>beginning of the document, or the end?

This is a moot point.  People DO NOT type "scroll-up" in emacs, they
use a key stroke instead.  All you need to know is Control-V is down,
and Meta-V is opposite.

>   It seems to me that there's a very strong convention of moving
>"down" meaning moving to a later part in the text; i.e. the observer
>is moving, not the text.

Uh, emacs should change because all the new squirts on the block
decided to use different names?  And even if emacs changed, it's
not big deal, since no one ever types in that function name unless
they've reached the point where they won't get confused.

Next there will be this silly argument that "execute-extended-command"
should be called something else, since that isn't the name VI uses.

>I just think that for the sake of intuitiveness and consistency,
>the names scroll-up and scroll-down should have been chosen the other
>way.

At the time, picking either way would NOT have affected consistency
since there was not much to be inconsistent with.  And the intuitive
argument is invalid.
-- 
Darin Johnson
djohnson@ucsd.edu
    "I wonder what's taking Guybrush so long..."

In article <DAVIS.93Jan9133616@pacific.mps.ohio-state.edu> davis@pacific.mps.ohio-state.edu ("John E. Davis") writes:
   I agree that emacs definition of scroll-up/down is backward.  This is the
   reason that I chose to avoid the problem altogether for my JED editor.  In
   JED, the analogous primitives are called `page_up' and `page_down'.  Care to
   guess which does what?

Ok here's my guess: "page_up" moves the page up so that you see the
text on the _following_ page (vice versa for "page_down").

On the other hand: "page_up" means "page upwards" which means that it
moves to the text on the _previous_ page (vice versa for "page_down").

Given that I find my first guess more natural, I'll leave you to guess
which editor I use :-)

bevan

On 8 Jan 93 00:58:20 GMT, shibuya@bl.applicon.slb.com (Hiroto Shibuya) said:

shibuya> I just came across a fundamental difference between Emacs and
shibuya> VI, which I never noticed for a decade.

shibuya> THEY SCROLL UP/DOWN IN DIFFERENT DIRECTION!

This is not quite a correct statement. There is no difference.

shibuya> Emacs command "scroll-up" scroll the text up so you see the
					  ^^^^^^^^
shibuya> text further down.  VI command ^U, is described in the manual
shibuya> as "scroll up", which scroll the text down so you see the text
				      ^^^^^^^^
shibuya> further up.

What happens really, and none of the people in the followups I have read
has pointed this out, is that Emacs scrolls the *text*, and vi scrolls
the *screen* (window).

The visual effect is on the intersection of the two (the current page);
if you move the window up, holding the text still, you see the preceding
page, and if you move the text up, holding the window still, you see the
following page.

References:

In emacs if you "(describe-function 'scroll-up)", you get:

	scroll-up:
	Scroll text of current window upward ARG lines; [ ... ]
	       ^^^^

If you "man vi"  you get:

          <CTRL/U>     Pages up half screen.
--
Piercarlo Grandi, Dept of CS, PC/UW@Aberystwyth <pcg@aber.ac.uk>
  E l'italiano cantava, cantava. E le sue disperate invocazioni giunsero
  alle orecchie del suo divino protettore, il dio della barzelletta

Following is a discussion found in Emacs Lisp Manual (thanks to
petonic@hal.com for pointing it out) which clearly state the existance
of two different way to look at the direction of scroll up/down, and
the reason for the choice made by Emacs.

------------------------------------------------

Vertical Scrolling
==================

   Vertical scrolling means moving the text up or down in a window.
It works by changing the value of the window's display-start
location.  It may also change the value of `window-point' to keep it
on the screen.

   In the commands `scroll-up' and `scroll-down', the directions "up"
and "down" refer to the motion of the text in the buffer at which you
are looking through the window.  Imagine that the text is written on
a long roll of paper and that the scrolling commands move the paper
up and down.  Thus, if you are looking at text in the middle of a
buffer and repeatedly call `scroll-down', you will eventually see the
beginning of the buffer.

   Some people have urged that the opposite convention be used: they
imagine that the window moves over text that remains in place.  Then
"down" commands would take you to the end of the buffer.  This view
is more consistent with the actual relationship between windows and
the text in the buffer, but it is less like what the user sees.  The
position of a window on the terminal does not move, and short
scrolling commands clearly move the text up or down on the screen.
We have chosen names that fit the user's point of view.

------------------------------------------------

I'm still curious which choice other editors are making.

					Hiroto Shibuya
			
					Applicon Inc.
					Billerica, MA
					U.S.A.