CUA-mode features and documenation (was: Re: change cursor type when idle)

[Kim F. Storm]

Stefan Monnier <address@hidden> writes:

> Even just a few starting hints would be good: how to enable each major
> feature (e.g. the cursor stuff, the rectangle stuff, ...).

The commentary in cua-base.el contains a few hints :-)

Some details of the info may be slightly inaccurate though.


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This is the CUA package which provides a complete emulation of the
standard CUA key bindings (Motif/Windows/Mac GUI) for selecting and
manipulating the region where S-<movement> is used to highlight &
extend the region.

CUA style key bindings for cut and paste
----------------------------------------

This package allows the C-z, C-x, C-c, and C-v keys to be
bound appropriately according to the Motif/Windows GUI, i.e.
C-z     -> undo
C-x     -> cut
C-c     -> copy
C-v     -> paste

The tricky part is the handling of the C-x and C-c keys which
are normally used as prefix keys for most of emacs' built-in
commands.  With CUA they still do!!!

Only when the region is currently active (and highlighted since
transient-mark-mode is used), the C-x and C-c keys will work as CUA
keys
        C-x -> cut
        C-c -> copy
When the region is not active, C-x and C-c works as prefix keys!

This probably sounds strange and difficult to get used to - but
based on my own experience and the feedback from many users of
this package, it actually works very well and users adapt to it
instantly - or at least very quickly.  So give it a try!
.. and in the few cases where you make a mistake and accidentally
delete the region - you just undo the mistake (with C-z).

If you really need to perform a command which starts with one of
the prefix keys even when the region is active, you have three options:
- press the prefix key twice very quickly (within 0.2 seconds),
- press the prefix key and the following key within 0.2 seconds, or
- use the SHIFT key with the prefix key, i.e. C-X or C-C

This behaviour can be customized via the
cua-prefix-override-inhibit-delay variable.

In addition to using the shifted movement keys, you can also use
[C-space] to start the region and use unshifted movement keys to extend
it. To cancel the region, use [C-space] or [C-g].

If you prefer to use the standard emacs cut, copy, paste, and undo
bindings, customize cua-enable-cua-keys to nil.


Typing text replaces the region
-------------------------------

When the region is active, i.e. highlighted, the text in region is
replaced by the text you type.

The replaced text is saved in register 0 which can be inserted using
the key sequence M-0 C-v (see the section on register support below).

If you have just replaced a highlighted region with typed text,
you can repeat the replace with M-v.  This will search forward
for a streach of text identical to the previous contents of the
region (i.e. the contents of register 0) and replace it with the
text you typed to replace the original region.  Repeating M-v will
replace the next matching region and so on.

Example:  Suppose you have a line like this
  The redo operation will redo the last redoable command
which you want to change into
  The repeat operation will repeat the last repeatable command
This is done by highlighting the first occurrence of "redo"
and type "repeat" M-v M-v.

Note: Since CUA-mode duplicates the functionality of the
delete-selection-mode, that mode is automatically disabled when
CUA-mode is enabled.


CUA mode indications
--------------------
You can choose to let CUA use different cursor colors to indicate
overwrite mode and read-only buffers.  For example, the following
setting will use a RED cursor in normal (insertion) mode in
read-write buffers, a YELLOW cursor in overwrite mode in read-write
buffers, and a GREEN cursor read-only buffers:

 (setq cua-normal-cursor-color "red")
 (setq cua-overwrite-cursor-color "yellow")
 (setq cua-read-only-cursor-color "green")


CUA register support
--------------------
Emacs' standard register support is also based on a separate set of
"register commands".

CUA's register support is activated by providing a numeric
prefix argument to the C-x, C-c, and C-v commands. For example,
to copy the selected region to register 2, enter [M-2 C-c].
Or if you have activated the keypad prefix mode, enter [kp-2 C-c].

And CUA will copy and paste normal region as well as rectangles
into the registers, i.e. you use exactly the same command for both.

In addition, the last highlighted text that is deleted (not
copied), e.g. by [delete] or by typing text over a highlighted
region, is automatically saved in register 0, so you can insert it
using [M-0 C-v].

CUA rectangle support
---------------------
Emacs' normal rectangle support is based on interpreting the region
between the mark and point as a "virtual rectangle", and using a
completely separate set of "rectangle commands" [C-x r ...] on the
region to copy, kill, fill a.s.o. the virtual rectangle.

cua-mode's superior rectangle support uses a true visual
representation of the selected rectangle, i.e. it highlights the
actual part of the buffer that is currently selected as part of the
rectangle.  Unlike emacs' traditional rectangle commands, the
selected rectangle always as straight left and right edges, even
when those are in the middle of a TAB character or beyond the end
of the current line.  And it does this without actually modifying
the buffer contents (it uses display overlays to visualize the
virtual dimensions of the rectangle).

This means that cua-mode's rectangles are not limited to the actual
contents of the buffer, so if the cursor is currently at the end of a
short line, you can still extend the rectangle to include more columns
of longer lines in the same rectangle.  And you can also have the
left edge of a rectangle start in the middle of a TAB character.
Sounds strange? Try it!

To start a rectangle, use [C-return] and extend it using the normal
movement keys (up, down, left, right, home, end, C-home,
C-end). Once the rectangle has the desired size, you can cut or
copy it using C-x and C-c (or C-w and M-w), and you can
subsequently insert it - as a rectangle - using C-v (or C-y).  So
the only new command you need to know to work with cua-mode
rectangles is C-return!

Normally, when you paste a rectangle using C-v (C-y), each line of
the rectangle is inserted into the existing lines in the buffer.
If overwrite-mode is active when you paste a rectangle, it is
inserted as normal (multi-line) text.

If you prefer the traditional rectangle marking (i.e. don't want
straight edges), [M-p] toggles this for the current rectangle,
or you can customize cua-virtual-rectangle-edges.

And there's more: If you want to extend or reduce the size of the
rectangle in one of the other corners of the rectangle, just use
[return] to move the cursor to the "next" corner.  Or you can use
the [M-up], [M-down], [M-left], and [M-right] keys to move the
entire rectangle overlay (but not the contents) in the given
direction.

[C-return] cancels the rectangle
[C-space] activates the region bounded by the rectangle

If you type a normal (self-inserting) character when the rectangle is
active, the character is inserted on the "current side" of every line
of the rectangle.  The "current side" is the side on which the cursor
is currently located. If the rectangle is only 1 column wide,
insertion will be performed to the left when the cursor is at the
bottom of the rectangle.  So, for example, to comment out an entire
paragraph like this one, just place the cursor on the first character
of the first line, and enter the following:
    C-return M-} ; ; <space>  C-return

cua-mode's rectangle support also includes all the normal rectangle
functions with easy access:

[M-a] aligns all words at the left edge of the rectangle
[M-b] fills the rectangle with blanks (tabs and spaces)
[M-c] closes the rectangle by removing all blanks at the left edge
      of the rectangle
[M-f] fills the rectangle with a single character (prompt)
[M-i] increases the first number found on each line of the rectangle
      by the amount given by the numeric prefix argument (default 1)
      It recognizes 0x... as hexadecimal numbers
[M-k] kills the rectangle as normal multi-line text (for paste)
[M-l] downcases the rectangle
[M-m] copies the rectangle as normal multi-line text (for paste)
[M-n] fills each line of the rectangle with increasing numbers using
      a supplied format string (prompt)
[M-o] opens the rectangle by moving the highlighted text to the
      right of the rectangle and filling the rectangle with blanks.
[M-p] toggles virtual straight rectangle edges
[M-P] inserts tabs and spaces (padding) to make real straight edges
[M-q] performs text filling on the rectangle
[M-r] replaces REGEXP (prompt) by STRING (prompt) in rectangle
[M-R] reverse the lines in the rectangle
[M-s] fills each line of the rectangle with the same STRING (prompt)
[M-t] performs text fill of the rectangle with TEXT (prompt)
[M-u] upcases the rectangle
[M-|] runs shell command on rectangle
[M-'] restricts rectangle to lines with CHAR (prompt) at left column
[M-/] restricts rectangle to lines matching REGEXP (prompt)
[C-?] Shows a brief list of the above commands.

[M-C-up] and [M-C-down] scrolls the lines INSIDE the rectangle up
and down; lines scrolled outside the top or bottom of the rectangle
are lost, but can be recovered using [C-z].

CUA Global Mark
---------------
The final feature provided by CUA is the "global mark", which
makes it very easy to copy bits and pieces from the same and other
files into the current text.  To enable and cancel the global mark,
use [S-C-space].  The cursor will blink when the global mark
is active.  The following commands behave differently when the global
mark is set:
<ch>  All characters (including newlines) you type are inserted
      at the global mark!
[C-x] If you cut a region or rectangle, it is automatically inserted
      at the global mark, and the global mark is advanced.
[C-c] If you copy a region or rectangle, it is immediately inserted
      at the global mark, and the global mark is advanced.
[C-v] Copies a single character to the global mark.
[C-d] Moves (i.e. deletes and inserts) a single character to the
      global mark.
[backspace] deletes the character before the global mark, while
[delete] deltes the character after the global mark.

[S-C-space] Jumps to and cancels the global mark.
[C-u S-C-space] Cancels the global mark (stays in current buffer).

[TAB] Indents the current line or rectangle to the column of the
      global mark.

-- 
Kim F. Storm <address@hidden> http://www.cua.dk