Commit 37281adb authored by Richard M. Stallman's avatar Richard M. Stallman
Browse files

New node Momentary Mark.

Clarify text for Transient Mark mode.
C-u C-SPC repetition does not need the C-u.
parent dfa56e2b
......@@ -41,6 +41,7 @@ mark in the @dfn{mark ring}.
* Setting Mark:: Commands to set the mark.
* Transient Mark:: How to make Emacs highlight the region--
when there is one.
* Momentary Mark:: Enabling Transient Mark mode momentarily.
* Using Region:: Summary of ways to operate on contents of the region.
* Marking Objects:: Commands to put region around textual units.
* Mark Ring:: Previous mark positions saved so you can go back there.
......@@ -100,7 +101,7 @@ with the command @kbd{C-x C-x} (@code{exchange-point-and-mark}) which
puts the mark where point was and point where the mark was. The extent
of the region is unchanged, but the cursor and point are now at the
previous position of the mark. In Transient Mark mode, this command
reactivates the mark.
also reactivates the mark.
@kbd{C-x C-x} is also useful when you are satisfied with the position
of point but want to move the other end of the region (where the mark
......@@ -128,26 +129,29 @@ character, but its binding is still @code{set-mark-command}.
@cindex highlighting region
@cindex region highlighting
On a terminal that supports colors, Emacs can highlight the current
region. But normally it does not. Why not?
Highlighting the region whenever it exists would not be desirable in
Emacs, because once you have set a mark, there is @emph{always} a
region (in that buffer). And highlighting the region all the time
would be a nuisance. So normally Emacs highlights the region only
immediately after you have selected one with the mouse.
You can turn on region highlighting by enabling Transient Mark mode.
This is a more rigid mode of operation in which the region ``lasts''
only temporarily, so you must set up a region for each command that uses
one. In Transient Mark mode, most of the time there is no region;
therefore, highlighting the region when it exists is useful and
not annoying.
On a terminal that supports colors, Emacs has the ability to
highlight the current region. But normally it does not. Why not?
Once you have set the mark in a buffer, there is @emph{always} a
region in that buffer. This is because every command that sets the
mark also activates it, and nothing ever deactivates it. Highlighting
the region all the time would be a nuisance. So normally Emacs
highlights the region only immediately after you have selected one
with the mouse.
If you want region highlighting, you can use Transient Mark mode.
This is a more rigid mode of operation in which the region always
``lasts'' only until you use it; you explicitly must set up a region
for each command that uses one. In Transient Mark mode, most of the
time there is no region; therefore, highlighting the region when it
exists is useful and not annoying. When Transient Mark mode is
enabled, Emacs always highlights the region whenever there is a
region.
@findex transient-mark-mode
To enable Transient Mark mode, type @kbd{M-x transient-mark-mode}.
This command toggles the mode, so you can repeat the command to turn off
the mode.
This command toggles the mode; you can use the same command to turn
the mode off again.
Here are the details of Transient Mark mode:
......@@ -164,6 +168,9 @@ keyboard commands whose purpose is to specify a region, including
@kbd{M-@@}, @kbd{C-M-@@}, @kbd{M-h}, @kbd{C-M-h}, @kbd{C-x C-p}, and
@kbd{C-x h}.
@item
You can tell that the mark is active because the region is highlighted.
@item
When the mark is active, you can execute commands that operate on the
region, such as killing, indenting, or writing to a file.
......@@ -174,6 +181,9 @@ deactivates the mark. This means any subsequent command that operates
on a region will get an error and refuse to operate. You can make the
region active again by typing @kbd{C-x C-x}.
@item
Quitting with @kbd{C-g} deactivates the mark.
@item
Commands like @kbd{M->} and @kbd{C-s}, that ``leave the mark behind'' in
addition to some other primary purpose, do not activate the new mark.
......@@ -184,15 +194,12 @@ You can activate the new region by executing @kbd{C-x C-x}
@kbd{C-s} when the mark is active does not alter the mark.
@item
Quitting with @kbd{C-g} deactivates the mark.
@item
Some commands operate on the region whenever it is active. For
instance, @kbd{C-x u} in Transient Mark mode operates on the region
when there is a region. Outside Transient Mark mode, you must type
@kbd{C-u C-x u} if you want it to operate on the region.
@xref{Undo}. Other commands that act this way are identified
in their own documentation.
Some commands operate on the region if a region is active. For
instance, @kbd{C-x u} in Transient Mark mode operates on the region,
when there is a region. (Outside Transient Mark mode, you must type
@kbd{C-u C-x u} if you want it to operate on the region.)
@xref{Undo}. Other commands that act this way are identified in their
own documentation.
@end itemize
The highlighting of the region uses the @code{region} face; you can
......@@ -208,21 +215,53 @@ variable @code{highlight-nonselected-windows} is non-@code{nil}, then
each window highlights its own region (provided that Transient Mark mode
is enabled and the mark in the window's buffer is active).
When Transient Mark mode is not enabled, every command that sets the
mark also activates it, and nothing ever deactivates it.
@vindex mark-even-if-inactive
If the variable @code{mark-even-if-inactive} is non-@code{nil} in
Transient Mark mode, then commands can use the mark and the region
even when it is inactive. Region highlighting appears and disappears
even when it is inactive. Region highlighting appears and disappears
just as it normally does in Transient Mark mode, but the mark doesn't
really go away when the highlighting disappears.
really go away when the highlighting disappears, so you can still use
region commands.
@cindex Zmacs mode
Transient Mark mode is also sometimes known as ``Zmacs mode''
because the Zmacs editor on the MIT Lisp Machine handled the mark in a
similar way.
@node Momentary Mark
@section Using Transient Mark Mode Momentarily
If you don't like Transient Mark mode in general, you might still
want to use it once in a while. To do this, type @kbd{C-@key{SPC}
C-@key{SPC}} or @kbd{C-u C-x C-x}. These commands set or activate the
mark, and enable Transient Mark mode only until the mark is
deactivated.
@table @kbd
@item C-@key{SPC} C-@key{SPC}
@kindex C-@key{SPC} C-@key{SPC}
Set the mark at point (like plain @kbd{C-@key{SPC}}), and enable
Transient Mark mode just once until the mark is deactivated. (This is
not really a separate command; you are using the @kbd{C-@key{SPC}}
command twice.)
@item C-u C-x C-x
@kindex C-u C-x C-x
Activate the mark without changing it, enable Transient Mark mode just
once until the mark is deactivated. (This is the @kbd{C-x C-x} command,
@code{exchange-point-and-mark}, with a prefix argument.)
@end table
One of the secondary features of Transient Mark mode is that certain
commands operate on the region when there is an active region. If you
don't use Transient Mark mode, the region once set never becomes
inactive, so there is no way these commands to make such a
distinction. Enabling Transient Mark mode momentarily gives you a way
to use these commands on the region.
The other way momentarily use of Transient Mark mode is useful
is that it highlights the region for the time being.
@node Using Region
@section Operating on the Region
......@@ -329,9 +368,12 @@ old mark onto this ring. To return to a marked location, use @kbd{C-u
C-@key{SPC}} (or @kbd{C-u C-@@}); this is the command
@code{set-mark-command} given a numeric argument. It moves point to
where the mark was, and restores the mark from the ring of former
marks. Thus, repeated use of this command moves point to all of the old
marks on the ring, one by one. The mark positions you move through in
this way are not lost; they go to the end of the ring.
marks.
If you repeat the character @kbd{C-@key{SPC}}, after typing @kbd{C-u
C-@key{SPC}}, each repetition moves point to a previous mark position
from the ring. The mark positions you move through in this way are
not lost; they go to the end of the ring.
Each buffer has its own mark ring. All editing commands use the current
buffer's mark ring. In particular, @kbd{C-u C-@key{SPC}} always stays in
......
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