2 Improvements over Vi
Some common problems with Vi and Ex have been solved in Viper. This
includes better implementation of existing commands, new commands, and
the facilities provided by Emacs.
2.1 Basics
The Vi command set is based on the idea of combining motion commands
with other commands. The motion command is used as a text region
specifier for other commands.
We classify motion commands into point commands and
line commands.
The point commands are:
h, l, 0, $, w, W, b, B,
e, E, (, ), /, ?, `, f,
F, t, T, %, ;, ,, ^
The line commands are:
j, k, +, -, H, M, L, {,
}, G, ', [[, ]], []
If a point command is given as an argument to a modifying command, the
region determined by the point command will be affected by the modifying
command. On the other hand, if a line command is given as an argument to a
modifying command, the region determined by the line command will be
enlarged so that it will become the smallest region properly containing the
region and consisting of whole lines (we call this process expanding
the region), and then the enlarged region will be affected by the modifying
command.
Text Deletion Commands (see Deleting Text), Change commands
(see Changing Text), even Shell Commands (see Shell Commands)
use these commands to describe a region of text to operate on.
Thus, type dw to delete a word, >} to shift a paragraph, or
!'afmt to format a region from ‘point’ to textmarker
‘a’.
Viper adds the region specifiers ‘r’ and ‘R’. Emacs has a
special marker called mark. The text-area between the current cursor
position point and the mark is called the region.
‘r’ specifies the raw region and ‘R’ is the expanded region
(i.e., the minimal contiguous chunk of full lines that contains the raw
region).
dr will now delete the region, >r will shift it, etc.
r,R are not motion commands, however. The special mark is set by
m. and other commands. See Marking, for more info.
Viper also adds counts to most commands for which it would make sense.
In the Overview chapter, some Multiple File issues were discussed
(see Multiple Files in Viper). In addition to the files, Emacs has
buffers. These can be seen in the :args list and switched using
:next if you type :set ex-cycle-through-non-files t, or
specify (setq ex-cycle-through-non-files t)
in your
Viper customization file. See Customization, for details.
2.2 Undo and Backups
Viper provides multiple undo. The number of undo’s and the size is limited
by the machine. The Viper command u does an undo. Undo can be
repeated by typing . (a period). Another u will undo the undo,
and further
. will repeat it. Typing u does the first undo, and changes the
direction.
Since the undo size is limited, Viper can create backup files and
auto-save files. It will normally do this automatically. It is possible
to have numbered backups, etc. For details, see Backup and
Auto-Save in The GNU Emacs Manual.
The results of the 9 previous changes are available in the 9 numeric
registers, as in Vi. The extra goody is the ability to view these
registers, in addition to being able to access them through p and
M-y (See Insert State, for details.)
The Viper command ] register will display the contents of any
register, numeric or alphabetical. The related command [ textmarker
will show the text around the textmarker. ‘register’ and ‘textmarker’
can be any letters from a through z.
2.3 History
History is provided for Ex commands, Vi searches, file names, pieces of
text inserted in earlier commands that use Insert or Replace state, and for
destructive commands in Vi state. These are
useful for fixing those small typos that screw up searches and :s,
and for eliminating routine associated with repeated typing of file names
or pieces of text that need to be inserted frequently.
At the : or / prompts in the minibuffer, you can do the following:
- M-p and M-n
To move to previous and next history items. This causes the history
items to appear on the command line, where you can edit them, or
simply type Return to execute.
- M-r and M-s
To search backward and forward through the history.
- RET
Type RET to accept a default (which is displayed in the prompt).
The history of insertions can be perused by
typing C-c M-p and C-c M-n while in Insert or Replace state.
The history of destructive Vi commands can be perused via the same keys
when Viper is in Vi state. See Viper Specials, for details.
All Ex commands have a file history. For instance, typing :e, space
and then M-p will bring up the name of the previously typed file
name. Repeatedly typing M-p, M-n, etc., will let you browse
through the file history.
Similarly, commands that have to do with switching buffers
have a buffer history, and commands that expect strings or regular
expressions keep a history on those items.
2.4 Macros and Registers
Viper facilitates the use of Emacs-style keyboard macros. @# will
start a macro definition. As you type, the commands will be executed, and
remembered (This is called “learn mode” in some editors.)
@register will complete the macro, putting it into ‘register’,
where ‘register’ is any character from ‘a’ through ‘z’. Then
you can execute this macro using @register. It is, of course,
possible to yank some text into a register and execute it using
@register. Typing @@, @RET, or @C-j will
execute the last macro that was executed using @register.
Viper will automatically lowercase the register, so that pressing the
SHIFT key for @ will not create problems. This is for
@ macros and "p only. In the case of y,
"Ayy will append to register a. For [,],',`, it
is an error to use a Uppercase register name.
The contents of a register can be seen by ]register. ([textmarker
will show the contents of a textmarker).
The last keyboard macro can also be executed using
*, and it can be yanked into a register using @!register.
This is useful for Emacs style keyboard macros defined using C-x(
and C-x). Emacs keyboard macros have more capabilities.
See Keyboard Macros in The GNU Emacs Manual, for
details.
Keyboard Macros allow an interesting form of Query-Replace:
/pattern or n to go to the next pattern (the query), followed by a
Keyboard Macro execution @@ (the replace).
Viper also provides Vi-style macros. See Vi Macros, for details.
2.5 Completion
Completion is done when you type TAB. The Emacs completer does not
grok wildcards in file names. Once you type a wildcard, the completer will
no longer work for that file name. Remember that Emacs interprets a file name
of the form /foo//bar as /bar and /foo/~/bar as
~/bar.
2.6 Improved Search
Viper provides buffer search, the ability to search the buffer for a region
under the cursor. You have to turn this on in your Viper customization file
either by calling
(viper-buffer-search-enable)
or by setting viper-buffer-search-char
to, say, f3:
(setq viper-buffer-search-char ?g)
If the user calls viper-buffer-search-enable
explicitly (the first
method), then viper-buffer-search-char
will be set to g.
Regardless of how this feature is enabled, the key
viper-buffer-search-char
will take movement commands, like
w,/,e, to find a region and then search for the contents of that
region. This command is very useful for searching for variable names, etc.,
in a program. The search can be repeated by n or reversed by N.
Emacs provides incremental search. As you type the string in, the
cursor will move to the next match. You can snarf words from the buffer
as you go along. Incremental Search is normally bound to C-s and
C-r. See Customization, to find out how to change the bindings
of C-r or C-s.
For details, see Incremental
Search in The GNU Emacs Manual.
Viper also provides a query replace function that prompts through the
minibuffer. It is invoked by the Q key in Vi state.
On a window display, Viper supports mouse search, i.e., you can search for a
word by clicking on it. See Viper Specials, for details.
Finally, on a window display, Viper highlights search patterns as it finds
them. This is done through what is known as faces in Emacs. The
variable that controls how search patterns are highlighted is
viper-search-face
. If you don’t want any highlighting at all, put
(copy-face 'default 'viper-search-face)
in your Viper customization file. If you want to change how patterns are
highlighted, you will have to change viper-search-face
to your liking.
The easiest way to do this is to use Emacs customization widget, which is
accessible from the menubar. Viper customization group is located under the
Emulations customization group, which in turn is under the
Editing group (or simply by typing :customize). All Viper
faces are grouped together under Viper’s
Highlighting group.
Try it: it is really simple!
2.7 Abbreviation Facilities
It is possible in Emacs to define abbrevs based on the contents of the
buffer.
Sophisticated templates can be defined using the Emacs abbreviation
facilities. See Abbreviations in The GNU Emacs Manual, for
details.
Emacs also provides Dynamic Abbreviations. Given a partial word, Emacs
will search the buffer to find an extension for this word. For instance,
one can type ‘Abbreviations’ by typing ‘A’, followed by a keystroke
that completed the ‘A’ to ‘Abbreviations’. Repeated typing
will search further back in the buffer, so that one could get
‘Abbrevs’ by repeating the
keystroke, which appears earlier in the text. Emacs binds this to
ESC /, so you will have to find a key and bind the function
dabbrev-expand
to that key.
Facilities like this make Vi’s :ab command obsolete.
2.8 Movement and Markers
Viper can be set free from the line-limited movements in Vi, such as l
refusing to move beyond the line, ESC moving one character back,
etc. These derive from Ex, which is a line editor. If your
Viper customization file contains
(setq viper-ex-style-motion nil)
the motion will be a true screen editor motion. One thing you must then
watch out for is that it is possible to be on the end-of-line character.
The keys x and % will still work correctly, i.e., as if they
were on the last character.
The word-movement commands w, e, etc., and the associated
deletion/yanking commands, dw, yw, etc., can be made to
understand Emacs syntax tables. If the variable
viper-syntax-preference
is set to strict-vi
then
the meaning of word is the same as in
Vi. However, if the value is reformed-vi
(the default) then the
alphanumeric symbols will be those specified by the current Emacs syntax
table (which may be different for different major modes) plus the
underscore symbol _, minus some non-word symbols, like ’.;,|, etc.
Both strict-vi
and reformed-vi
work close to Vi in
traditional cases, but reformed-vi
does a better job when editing
text in non-Latin alphabets.
The user can also specify the value emacs
, which would
make Viper use exactly the Emacs notion of word. In particular, the
underscore may not be part of a word. Finally, if
viper-syntax-preference
is set to extended
, Viper words would
consist of characters that are classified as alphanumeric or as
parts of symbols. This is convenient for writing programs and in many other
situations.
viper-syntax-preference
is a local variable, so it can have different
values for different major modes. For instance, in programming modes it can
have the value extended
. In text modes where words contain special
characters, such as European (non-English) letters, Cyrillic letters, etc.,
the value can be reformed-vi
or emacs
.
Changes to viper-syntax-preference
should be done in the hooks to
various major modes by executing viper-set-syntax-preference
as in
the following example:
(viper-set-syntax-preference nil "emacs")
The above discussion of the meaning of Viper’s words concerns only Viper’s
movement commands. In regular expressions, words remain the same as in
Emacs. That is, the expressions \w
, \>
, \<
, etc., use
Emacs’s idea of what is a word, and they don’t look into the value of
variable viper-syntax-preference
. This is because Viper doesn’t change
syntax tables in fear of upsetting the various major modes that set these
tables.
Textmarkers in Viper remember the file and the position, so that you can
switch files by simply doing 'a. If you set up a regimen for using
Textmarkers, this is very useful. Contents of textmarkers can be viewed
by [marker. (Contents of registers can be viewed by ]register).
2.9 New Commands
These commands have no Vi analogs.
- C-x, C-c ¶
-
These two keys invoke many important Emacs functions. For example, if you
hit C-x followed by 2, then the current window will be split
into 2. Except for novice users, C-c is also set to execute an Emacs
command from the current major mode. ESC will do the same, if you
configure ESC as Meta by setting viper-no-multiple-ESC
to
nil
in your Viper customization file. See Customization.
C-\ in Insert, Replace, or Vi states will make Emacs think
Meta has been hit.
- \ ¶
Escape to Emacs to execute a single Emacs command. For instance,
\ ESC will act like a Meta key.
- Q ¶
-
Q is for query replace. By default,
each string to be replaced is treated as a regular expression. You can use
(setq viper-re-query-replace nil)
in your .emacs file to
turn this off. (For normal searches, :se nomagic will work. Note
that :se nomagic turns Regexps off completely, unlike Vi).
- v ¶
- V
- C-v
-
These keys are used to visit files. v will switch to a buffer
visiting file whose name can be entered in the minibuffer. V is
similar, but will use a window different from the current window.
C-v is like V, except that a new frame (X window) will be used
instead of a new Emacs window.
- # ¶
If followed by a certain character ch, it becomes an operator whose
argument is the region determined by the motion command that follows
(indicated as <move>).
Currently, ch can be one of c, C, g, q, and
s. For instance, #qr will prompt you for a string and then
prepend this string to each line in the buffer.
- # c ¶
-
Change upper-case characters in the region to lower-case
(downcase-region
).
Emacs command M-l does the same for words.
- # C ¶
Change lower-case characters in the region to upper-case. For instance,
# C 3 w will capitalize 3 words from the current point
(upcase-region
).
Emacs command M-u does the same for words.
- # g ¶
Execute last keyboard macro for each line in the region
(viper-global-execute
).
- # q ¶
Insert specified string at the beginning of each line in the region
(viper-quote-region
). The default string is composed of the comment
character(s) appropriate for the current major mode.
- # s ¶
Check spelling of words in the region (spell-region
).
The function used for spelling is determined from the variable
viper-spell-function
.
- * ¶
Call last keyboard macro.
- m .
Set mark at point and push old mark off the ring
- m<
- m>
Set mark at beginning and end of buffer, respectively.
- m,
Jump to mark and pop mark off the ring. See Mark in The GNU
Emacs Manual, for more info.
- ] register ¶
View contents of register
- [ textmarker ¶
View filename and position of textmarker
- @#
- @register
- @! ¶
-
Begin/end keyboard macro. @register has a different meaning when used after
a @#. See Macros and Registers, for details
- [] ¶
Go to end of heading.
- g <movement command>
Search buffer for text delimited by movement command. The canonical
example is gw to search for the word under the cursor.
See Improved Search, for details.
- C-g and C-] ¶
-
Quit and Abort Recursive edit. These may be necessary on occasion.
See Vi State, for a reason.
- C-c C-g ¶
Hitting C-c followed by C-g will display the information on the
current buffer. This is the same as hitting C-g in Vi, but, as
explained above, C-g is needed for other purposes in Emacs.
- C-c / ¶
Without a prefix argument, this command toggles
case-sensitive/case-insensitive search modes and plain vanilla/regular
expression search. With the prefix argument 1, i.e.,
1 C-c /, this toggles case-sensitivity; with the prefix argument 2,
toggles plain vanilla search and search using
regular expressions. See Viper Specials, for alternative ways to invoke
this function.
- M-p and M-n ¶
-
In the minibuffer, these commands navigate through the minibuffer
histories, such as the history of search strings, Ex commands, etc.
- C-s ¶
If the minibuffer is entered via a Viper search commands / or ?,
then typing this key inserts the last search string used by the
Emacs incremental search command (that is bound to C-s everywhere
except in this case).
- C-c M-p and C-c M-n ¶
-
In Insert or Replace state, these commands let the user
peruse the history of insertion strings used in previous insert or replace
commands. Try to hit C-c M-p or C-c M-n repeatedly and see what
happens. See Viper Specials, for more.
In Vi state, these commands let the user peruse the history of Vi-style
destructive commands, such as dw, J, a, etc.
By repeatedly typing C-c M-p or C-c M-n you will cycle Viper
through the recent history of Vi commands, displaying the commands one by
one. Once an appropriate command is found, it can be executed by
typing a period.
Since typing C-c M-p is tedious, it is more convenient to bind an
appropriate function to a function key on the keyboard and use that key.
See Viper Specials, for details.
- Ex commands ¶
-
The commands :args, :next, :pre behave
differently. :pwd exists to get current directory.
The commands :b and :B switch buffers around. See File and Buffer Handling, for details.
There are also the new commands :RelatedFile and
PreviousRelatedFile (which abbreviate to R and P,
respectively. See Viper Specials, for details.
Apart from the new commands, many old commands have been enhanced. Most
notably, Vi style macros are much more powerful in Viper than in Vi. See Vi Macros, for details.
2.10 Useful Packages
Some Emacs packages are mentioned here as an aid to the new Viper user, to
indicate what Viper is capable of.
A vast number comes with the standard Emacs distribution, and many more exist
on the net and on the archives.
This manual also mentions some Emacs features a new user
should know about. The details of these are found in the GNU Emacs
Manual.
The features first. For details, look up the Emacs Manual.
- ‘Make’ ¶
-
Makes and Compiles can be done from the editor. Error messages will be
parsed and you can move to the error lines.
- ‘Shell’ ¶
-
You can talk to Shells from inside the editor. Your entire shell session
can be treated as a file.
- ‘Mail’ ¶
-
Mail can be read from and sent within the editor. Several sophisticated
packages exist.
- ‘Language Sensitive Editing’
Editing modes are written for most computer languages in existence. By
controlling indentation, they catch punctuation errors.
The packages, below, represents a drop in the sea of special-purpose
packages that come with standard distribution of Emacs.
- ‘Transparent FTP’ ¶
-
ange-ftp.el
can ftp from the editor to files on other machines
transparent to the user.
- ‘RCS Interfaces’ ¶
-
vc.el
for doing RCS commands from inside the editor
- ‘Directory Editor’ ¶
-
dired.el
for editing contents of directories and for navigating in
the file system.
- ‘Syntactic Highlighting’ ¶
-
font-lock.el
for automatic highlighting various parts of a buffer
using different fonts and colors.
- ‘Saving Emacs Configuration’ ¶
-
desktop.el
for saving/restoring configuration on Emacs exit/startup.
- ‘Spell Checker’ ¶
-
ispell.el
for spell checking the buffer, words, regions, etc.
- ‘File and Buffer Comparison’ ¶
-
ediff.el
for finding differences between files and for applying
patches.
Emacs Lisp archives exist on
‘archive.cis.ohio-state.edu’
and ‘wuarchive.wustl.edu’
3 Customization
Customization can be done in 2 ways.
-
Elisp code in a ~/.emacs.d/viper (or ~/.viper) file.
Viper loads this file just before it does the binding for mode hooks.
This is recommended for experts only.
-
Elisp code in your .emacs file before and after the
(require
'viper)
line. This method is not recommended, unless you know what
you are doing. Only two variables, viper-mode
and
viper-custom-file-name
, are supposed to be customized in .emacs,
prior to loading Viper (i.e., prior to (require 'viper)
command.
-
By executing the :customize Ex command. This takes you to the Emacs
customization widget, which lets you change the values of Viper
customizable variables easily. This method is good for novice and
experts alike. The customization code in the form of Lisp commands will be
placed in ~/.emacs or some other customization file depending on the
version of Emacs that you use. Still, it is recommended to separate
Viper-related customization produced by the Emacs customization widget
and keep it in your Viper customization file.
Some advanced customization cannot be accomplished this way, however, and
has to be done in Emacs Lisp in your Viper customization file. For the common
cases, examples are provided that you can use directly.
3.1 Rudimentary Changes
An easy way to customize Viper is to change the values of constants used in
Viper. Here is the list of the constants used in Viper and their default
values. The corresponding :se command is also indicated. (The symbols
t
and nil
represent “true” and “false” in Lisp).
Viper supports both the abbreviated Vi variable names and their full
names. Variable completion is done on full names only. TAB and
SPC complete
variable names. Typing = will complete the name and then will prompt for
a value, if applicable. For instance, :se au SPC will complete the
command to :set autoindent; :se ta SPC will complete the command
and prompt further like this: :set tabstop = .
However, typing :se ts SPC will produce a “No match” message
because ts is an abbreviation for tabstop and Viper supports
completion on full names only. However, you can still hit RET
or =, which will complete the command like this: :set ts = and
Viper will be waiting for you to type a value for the tabstop variable.
To get the full list of Vi variables, type :se SPC TAB.
viper-auto-indent nil
:se ai (:se autoindent)
:se ai-g (:se autoindent-global)
If t
, enable auto indentation.
by RET, o or O command.
viper-auto-indent
is a local variable. To change the value globally, use
setq-default
. It may be useful for certain major modes to have their
own values of viper-auto-indent
. This can be achieved by using
setq
to change the local value of this variable in the hooks to the
appropriate major modes.
:se ai changes the value of viper-auto-indent
in the current
buffer only; :se ai-g does the same globally.
viper-electric-mode t
If not nil
, auto-indentation becomes electric, which means that
RET, O, and o indent cursor according to the current
major mode. In the future, this variable may control additional electric
features.
This is a local variable: setq
changes the value of this variable
in the current buffer only. Use setq-default
to change the value in
all buffers.
viper-case-fold-search nil
:se ic (:se ignorecase)
If not nil
, search ignores cases.
This can also be toggled by quickly hitting / twice.
viper-re-search nil
:se magic
If not nil
, search will use regular expressions; if nil
then
use vanilla search.
This behavior can also be toggled by quickly hitting / trice.
buffer-read-only
:se ro (:se readonly)
Set current buffer to read only. To change globally put
(setq-default buffer-read-only t)
in your .emacs file.
blink-matching-paren t
:se sm (:se showmatch)
Show matching parens by blinking cursor.
tab-width t (default setting via setq-default
)
:se ts=value (:se tabstop=value)
:se ts-g=value (:se tabstop-global=value)
tab-width
is a local variable that controls the width of the tab stops.
To change the value globally, use setq-default
; for local settings,
use setq
.
The command :se ts
sets the tab width in the current
buffer only; it has no effect on other buffers.
The command :se ts-g sets tab width globally,
for all buffers where the tab is not yet set locally,
including the new buffers.
Note that typing TAB normally
doesn’t insert the tab, since this key is usually bound to
a text-formatting function, indent-for-tab-command
(which facilitates
programming and document writing). Instead, the tab is inserted via the
command viper-insert-tab
, which is bound to S-tab (shift + tab).
On some non-windowing terminals, Shift doesn’t modify the TAB key, so
S-tab behaves as if it were TAB. In such a case, you will have
to bind viper-insert-tab
to some other convenient key.
viper-shift-width 8
:se sw=value (:se shiftwidth=value)
The number of columns shifted by > and < commands.
viper-search-wrap-around t
:se ws (:se wrapscan)
If not nil
, search wraps around the end/beginning of buffer.
viper-search-scroll-threshold 2
If search lands within this many lines of the window top or bottom, the
window will be scrolled up or down by about 1/7-th of its size, to reveal
the context. If the value is negative, don’t scroll.
viper-tags-file-name "TAGS"
The name of the file used as the tag table.
viper-re-query-replace nil
If not nil
, use reg-exp replace in query replace.
viper-want-ctl-h-help nil
If not nil
, C-h is bound to help-command
;
otherwise, C-h is bound as usual in Vi.
viper-vi-style-in-minibuffer t
If not nil
, Viper provides a high degree of compatibility with Vi
insert mode when you type text in the minibuffer; if nil
, typing in
the minibuffer feels like plain Emacs.
viper-no-multiple-ESC t
If you set this to nil
, you can use ESC as Meta in Vi state.
Normally, this is not necessary, since graphical displays have separate
Meta keys (usually on each side of the space bar). On a dumb terminal, Viper
sets this variable to twice
, which is almost like nil
, except
that double ESC beeps. This, too, lets ESC to be used as a Meta.
viper-fast-keyseq-timeout 200
Key sequences separated by this many milliseconds are treated as Vi-style
keyboard macros. If the key sequence is defined as such a macro, it will be
executed. Otherwise, it is processed as an ordinary sequence of typed keys.
Setting this variable too high may slow down your typing. Setting it too
low may make it hard to type macros quickly enough.
viper-ex-style-motion t
Set this to nil
, if you want l,h to cross
lines, etc. See Movement and Markers, for more info.
viper-ex-style-editing t
Set this to nil
, if you want
C-h and DEL to not stop
at the beginning of a line in Insert state, X and x to delete
characters across lines in Vi command state, etc.
viper-ESC-moves-cursor-back t
It t
, cursor moves back 1 character when switching from insert state to vi
state. If nil
, the cursor stays where it was before the switch.
viper-always t
t
means: leave it to Viper to decide when a buffer must be brought
up in Vi state,
Insert state, or Emacs state. This heuristic works well in virtually all
cases. nil
means you either have to invoke viper-mode
manually
for each buffer (or you can add viper-mode
to the appropriate major mode
hooks using with-eval-after-load
).
This option must be set in your Viper customization file.
viper-custom-file-name "~/.emacs.d/viper"
File used for Viper-specific customization.
Change this setting, if you want. Must be set in .emacs
before Viper is loaded. Note that you
have to set it as a string inside double quotes.
viper-spell-function 'ispell-region
Function used by the command #c<move> to spell.
viper-glob-function
The value of this variable is the function symbol used to expand wildcard
symbols. This is platform-dependent. The default tries to set this variable
to work with most shells, MS Windows, etc. However, if it
doesn’t work the way you expect, you should write your own.
Use viper-glob-unix-files
and viper-glob-mswindows-files
in
viper-util.el as examples.
This feature is used to expand wildcards in the Ex command :e.
Note that Viper doesn’t support wildcards in the :r and :w
commands, because file completion is a better mechanism.
ex-cycle-other-window t
If not nil
, :n and :b will cycle through files in another
window, if one exists.
ex-cycle-through-non-files nil
:n does not normally cycle through buffers. Set this to get
buffers also.
viper-want-emacs-keys-in-insert
This is set to nil
for user levels 1 and 2 and to t
for user
levels 3 and 4. Users who specify level 5 are allowed to set this variable
as they please (the default for this level is t
). If set to
nil
, complete Vi compatibility is provided in Insert state. This is
really not recommended, as this precludes you from using language-specific
features provided by the major modes.
viper-want-emacs-keys-in-vi
This is set to nil
for user
level 1 and to t
for user levels 2–4.
At level 5, users are allowed to set this variable as they please (the
default for this level is t
).
If set to nil
, complete Vi compatibility is provided
in Vi command state. Setting this to nil
is really a bad idea,
unless you are a novice, as this precludes the use
of language-specific features provided by the major modes.
viper-keep-point-on-repeat t
If not nil
, point is not moved when the user repeats the previous
command by typing a period. This is very useful for doing repeated
changes with the . key.
viper-repeat-from-history-key 'f12
Prefix key used to invoke the macros f12 1 and f12 2 that repeat
the second-last and the third-last destructive command.
Both these macros are bound (as Viper macros) to
viper-repeat-from-history
,
which checks the second key by which it is invoked to see which of the
previous commands to invoke. Viper binds f12 1 and f12 2 only,
but the user can bind more in his/her Viper customization file.
See Vi Macros, for how to do this.
viper-keep-point-on-undo nil
If not nil
, Viper tries to not move point when undoing commands.
Instead, it will briefly move the cursor to the place where change has
taken place. However, if the undone piece of text is not seen in window,
then point will be moved to the place where the change took place.
Set it to t
and see if you like it better.
viper-delete-backwards-in-replace nil
If not nil
, DEL key will delete characters while moving the cursor
backwards. If nil
, the cursor will move backwards without deleting
anything.
viper-replace-overlay-face 'viper-replace-overlay-face
On a graphical display, Viper highlights replacement regions instead of
putting a ‘$’ at the end. This variable controls the so called
face used to highlight the region.
By default, viper-replace-overlay-face
underlines the replacement on
monochrome displays and also lays a stipple over them. On color displays,
replacement regions are highlighted with color.
If you know something about Emacs faces and don’t like how Viper highlights
replacement regions, you can change viper-replace-overlay-face
by
specifying a new face. (Emacs faces are described in the Emacs Lisp
reference.) On a color display, the following customization method is
usually most effective:
(set-face-foreground viper-replace-overlay-face "DarkSlateBlue")
(set-face-background viper-replace-overlay-face "yellow")
For a complete list of colors available to you, evaluate the expression
(defined-colors)
. (Type it in the buffer *scratch* and then
hit the C-j key.
viper-replace-overlay-cursor-color "Red"
¶
Cursor color when it is inside the replacement region.
This has effect only on color displays and only when Emacs runs as an X
application.
viper-insert-state-cursor-color nil
¶
If set to a valid color, this will be the cursor color when Viper is in
insert state.
viper-emacs-state-cursor-color nil
¶
If set to a valid color, this will be the cursor color when Viper is in
emacs state.
viper-replace-region-end-delimiter "$"
A string used to mark the end of replacement regions. It is used only on
TTYs or if viper-use-replace-region-delimiters
is non-nil
.
viper-replace-region-start-delimiter ""
A string used to mark the beginning of replacement regions. It is used
only on TTYs or if viper-use-replace-region-delimiters
is non-nil
.
viper-use-replace-region-delimiters
If non-nil
, Viper will always use viper-replace-region-end-delimiter
and
viper-replace-region-start-delimiter
to delimit replacement regions,
even on color displays (where this is unnecessary). By default, this
variable is non-nil
only on TTYs or monochrome displays.
viper-allow-multiline-replace-regions t
If non-nil
, multi-line text replacement regions, such as those produced by
commands c55w, 3C, etc., will stay around until the user exits
the replacement mode. In this variable is set to nil
, Viper will
emulate the standard Vi behavior, which supports only intra-line
replacement regions (and multi-line replacement regions are deleted).
viper-toggle-key "\C-z"
Specifies the key used to switch from Emacs to Vi and back.
Must be set in your Viper customization file. This variable can’t be
changed interactively after Viper is loaded.
In Insert state, this key acts as a temporary escape to Vi state, i.e., it
will set Viper up so that the very next command will be executed as if it
were typed in Vi state.
viper-buffer-search-char nil
Key used for buffer search. See Viper Specials, for details.
viper-surrounding-word-function 'viper-surrounding-word
The value of this variable is a function name that is used to determine
what constitutes a word clicked upon by the mouse. This is used by mouse
search and insert.
viper-search-face 'viper-search-face
Variable that controls how search patterns are highlighted when they are
found.
viper-vi-state-hook nil
List of parameterless functions to be run just after entering the Vi
command state.
viper-insert-state-hook nil
Same for Insert state. This hook is also run after entering Replace state.
viper-replace-state-hook nil
List of (parameterless) functions called just after entering Replace state
(and after all viper-insert-state-hook
).
viper-emacs-state-hook nil
List of (parameterless) functions called just after switching from Vi state
to Emacs state.
You can reset some of these constants in Viper with the Ex command :set
(when so indicated in the table). Or you
can include a line like this in your Viper customization file:
(setq viper-case-fold-search t)
3.2 Key Bindings
Viper lets you define hot keys, i.e., you can associate keyboard keys
such as F1, Help, PgDn, etc., with Emacs Lisp functions (that may already
exist or that you will write). Each key has a “preferred form” in
Emacs. For instance, the Up key’s preferred form is [up], the Help key’s
preferred form is [help], and the Undo key has the preferred form [f14].
You can find out the preferred form of a key by typing M-x
describe-key-briefly and then typing the key you want to know about.
Under the X Window System, every keyboard key emits its preferred form,
so you can just type
(global-set-key [f11] 'calendar) ; L1, Stop
(global-set-key [f14] 'undo) ; L4, Undo
to bind L1 (a key that exists on some SUN workstations) so it will invoke
the Emacs Calendar and to bind L4 so it will undo changes.
However, on a dumb terminal or in an Xterm window, even the standard arrow
keys may
not emit the right signals for Emacs to understand. To let Emacs know about
those keys, you will have to find out which key sequences they emit
by typing C-q and then the key (you should switch to Emacs state
first). Then you can bind those sequences to their preferred forms using
input-decode-map
as follows:
(cond ((string= (getenv "TERM") "xterm")
(define-key input-decode-map "\e[192z" [f11]) ; L1
(define-key input-decode-map "\e[195z" [f14]) ; L4, Undo
The above illustrates how to do this for Xterm. On VT100, you would have to
replace "xterm" with "vt100" and also change the key sequences (the same
key may emit different sequences on different types of terminals).
The above keys are global, so they are overwritten by the local maps
defined by the major modes and by Viper itself. Therefore, if you wish to
change a binding set by a major mode or by Viper, read this.
Viper users who wish to specify their own key bindings should be concerned
only with the following three keymaps:
viper-vi-global-user-map
for Vi state commands,
viper-insert-global-user-map
for Insert state commands,
and viper-emacs-global-user-map
for Emacs state commands (note:
customized bindings for Emacs state made to viper-emacs-global-user-map
are not inherited by Insert state).
For more information on Viper keymaps, see the header of the file
viper.el.
If you wish to change a Viper binding, you can use the
define-key
command, to modify viper-vi-global-user-map
,
viper-insert-global-user-map
, and viper-emacs-global-user-map
, as
explained below. Each of these key maps affects the corresponding Viper state.
The keymap viper-insert-global-user-map
also affects Viper’s Replace
state.
If you want to
bind a key, say C-v, to the function that scrolls
page down and to make 0 display information on the current buffer,
putting this in your Viper customization file will do the trick in Vi state:
(define-key viper-vi-global-user-map "\C-v" 'scroll-down)
To set a key globally,
(define-key viper-emacs-global-user-map "\C-c m" 'smail)
(define-key viper-vi-global-user-map "0" 'viper-info-on-file)
Note, however, that this binding may be overwritten by other keymaps, since
the global keymap has the lowest priority.
To make sure that nothing will override a binding in Emacs state, you
can write this:
(define-key viper-emacs-global-user-map "\C-c m" 'smail)
To customize the binding for C-h in Insert state:
(define-key viper-insert-global-user-map "\C-h"
'my-del-backwards-function)
Each Emacs command key calls some Lisp function. If you have enabled the
Help, (see Rudimentary Changes) C-h k will show you the function
for each specific key; C-h b will show all bindings, and C-h m
will provide information on the major mode in effect. If Help is not
enabled, you can still get help in Vi state by prefixing the above commands
with \, e.g., \ C-h k (or you can use the Help menu in the
menu bar, if Emacs runs under X).
Viper users can also change bindings on a per major mode basis. As with
global bindings, this can be done separately for each of the three main Viper
states. To this end, Viper provides the function
viper-modify-major-mode
.
To modify keys in Emacs state for my-favorite-major-mode
, the user
needs to create a sparse keymap, say, my-fancy-map
, bind whatever
keys necessary in that keymap, and put
(viper-modify-major-mode 'dired-mode 'emacs-state my-fancy-map)
in your Viper customization file. To do the same in Vi and Insert states, you
should use vi-state
and insert-state
. Changes in Insert state
are also in effect in Replace state. For instance, suppose that the user wants
to use dd in Vi state under Dired mode to delete files, u to unmark
files, etc. The following code in the Viper customization file will then do
the job:
(setq my-dired-modifier-map (make-sparse-keymap))
(define-key my-dired-modifier-map "dd" 'dired-flag-file-deletion)
(define-key my-dired-modifier-map "u" 'dired-unmark)
(viper-modify-major-mode 'dired-mode 'vi-state my-dired-modifier-map)
A Vi purist may want to modify Emacs state under Dired mode so that
k, l, etc., will move around in directory buffers, as in
Vi. Although this is not recommended, as these keys are bound to useful
Dired functions, the trick can be accomplished via the following code:
(setq my-dired-vi-purist-map (make-sparse-keymap))
(define-key my-dired-vi-purist-map "k" 'viper-previous-line)
(define-key my-dired-vi-purist-map "l" 'viper-forward-char)
(viper-modify-major-mode 'dired-mode
'emacs-state my-dired-vi-purist-map)
Yet another way to customize key bindings in a major mode is to edit the
list viper-major-mode-modifier-list
using the customization widget.
(This variable is in the Viper-misc customization group.)
The elements of this list are triples of the form: (major-mode viper-state
keymap), where the keymap contains bindings that are supposed to be active
in the given major mode and the given viper-state.
Effects similar to key binding changes can be achieved by defining Vi
keyboard macros using the Ex commands :map and :map!. The
difference is that multi-key Vi macros do not override the keys they are
bound to, unless these keys are typed in quick succession. So, with macros,
one can use the normal keys alongside with the macros. If per-mode
modifications are needed, the user can try both ways and see which one is
more convenient.
See Vi Macros, for details.
Note: in major modes that come up in Emacs state by default, the
aforesaid modifications may not take place immediately (but only after the
buffer switches to some other Viper state and then back to Emacs state). To
avoid this, one should add viper-change-state-to-emacs
to an
appropriate hook of that major mode. (Check the function
viper-set-hooks
in viper.el for examples.) However, if you
did not set viper-always
to nil
, chances are that you won’t
need to perform the above procedure, because Viper will take care of most
useful defaults.
Finally, Viper has a facility that lets the user define per-buffer
bindings, i.e., bindings that are in effect in some specific buffers
only. Unlike per-mode bindings described above, per-buffer bindings can be
defined based on considerations other than the major mode. This is done
via the function viper-add-local-keys
, which lets one specify bindings
that should be in effect in the current buffer only and for a specific Viper
state. For instance,
(viper-add-local-keys 'vi-state '(("ZZ" . TeX-command-master)
("ZQ" . viper-save-kill-buffer)))
redefines ZZ to invoke TeX-command-master
in vi-state
and ZQ to save-then-kill the current buffer. These bindings take
effect only in the buffer where this command is executed. The typical use
of this function is to execute the above expression from within a function
that is included in a hook to some major mode. For instance, the above
expression
could be called from a function, my-tex-init
, which may be added to
tex-mode-hook
as follows:
(add-hook 'tex-mode-hook 'my-tex-init)
When TeX mode starts, the hook is executed and the above Lisp expression is
evaluated. Then, the bindings for ZZ and ZQ are changed in Vi
command mode for all buffers in TeX mode.
Another useful application is to bind ZZ to send-mail
in the Mail mode buffers (the specifics of this depend on which mail
package you are using, rmail
, mh-e
, vm
, etc.
For instance, here is how to do this for mh-e
, the Emacs interface
to MH:
(defun mh-add-vi-keys ()
"Set up ZZ for MH-e and XMH."
(viper-add-local-keys 'vi-state '(("ZZ" . mh-send-letter))))
(add-hook 'mh-letter-mode-hook 'mh-add-vi-keys)
You can also use viper-add-local-keys
to set per buffer
bindings in Insert state and Emacs state by passing as a parameter the
symbols insert-state
and emacs-state
, respectively.
As with global bindings, customized local bindings done to Emacs state
are not inherited by Insert state.
On rare occasions, local keys may be added by mistake. Usually this is done
indirectly, by invoking a major mode that adds local keys (e.g.,
shell-mode
redefines RET). In such a case, exiting the wrong
major mode won’t rid you from unwanted local keys, since these keys are
local to Viper state and the current buffer, not to the major mode.
In such situations, the remedy is to type M-x viper-zap-local-keys.
So much about Viper-specific bindings.
See Customization in The GNU Emacs
Manual, and the Emacs quick reference card for the general info on key
bindings in Emacs.
3.3 Packages that Change Keymaps
Viper is designed to coexist with all major and minor modes of Emacs. This
means that bindings set by those modes are generally available with Viper
(unless you explicitly prohibit them by setting
viper-want-emacs-keys-in-vi
and viper-want-emacs-keys-in-insert
to
nil
).
If viper-always
is set to t
(which is the default), Viper
will try to bring each buffer
in the Viper state that is most appropriate for that buffer.
Usually, this would be the Vi state, but sometimes it could be the Insert
state or the Emacs state.
Some major mode bindings will necessarily be overwritten by Viper. Indeed, in
Vi state, most of the 1-character keys are used for Vi-style editing. This
usually causes no problems because most packages designed for editing files
typically do not bind such keys. Instead, they use key sequences that start
with C-x and C-c. This is why it was so important for us to
free up C-x and C-c.
It is common for language-specific major modes to bind TAB and
C-j (the line feed) keys to various formatting functions. This is
extremely useful, but may require some getting used to for a Vi user. If you
decide that this feature is not for you, you can re-bind these keys as
explained earlier (see Customization).
Binding for TAB is one of the most unusual aspects of Viper for many
novice users. In Emacs, TAB is used to format text and programs, and
is extremely useful. For instance, hitting TAB causes the current
line to be re-indented in accordance with the context. In programming,
this is very important, since improper automatic indentation would
immediately alert the programmer to a possible error. For instance, if a
) or a " is missing somewhere above the current
line, TAB is likely to mis-indent the line.
For this reason, Viper doesn’t change the standard Emacs binding of
TAB, thereby sacrificing Vi compatibility
(except for users at level 1). Instead, in Viper, the key
S-tab (shift+ tab) is chosen to emulate Vi’s TAB.
We should note that on some non-windowing terminals, Shift doesn’t modify
the TAB key, so S-tab behaves as if it were TAB. In such
a case, you will have to bind viper-insert-tab
to some other
convenient key.
Some packages, notably Dired, Gnus, Info, etc., attach special meaning to
common keys like SPC, x, d, v, and others. This
means that Vi command state is inappropriate for working with these
packages. Fortunately, these modes operate on read-only buffers and are
designed not for editing files, but for special-purpose browsing, reading
news, mail, etc., and Vi commands are meaningless in these situations. For
this reason, Viper doesn’t force Vi state on such major modes—it
brings them in Emacs state. You can switch to Vi state by typing C-z
if, for instance, you want to do Vi-style search in a buffer (although,
usually, incremental search, which is bound to C-s, is sufficient in
these situations). But you should then switch back to Emacs state if you
plan to continue using these major modes productively. You can also switch
to Vi temporarily, to execute just one command. This is done by typing
C-c \. (In some of these modes, / and : are bound
Vi-style, unless these keys perform essential duties.)
If you would like certain major modes to come up in Emacs state rather than
Vi state (but Viper thinks otherwise), you should put these major modes
on the viper-emacs-state-mode-list
list and delete them from
viper-vi-state-mode-list
.
Likewise, you can force Viper’s Insert state on a major mode by putting it
in viper-insert-state-mode-list
.
It is also possible to impose Vi on some major modes, even though they may
bind common keys to specialized commands. This might make sense for modes
that bind only a small number of common keys. For instance, Viper subverts
the Shell mode by changing the bindings for C-m and C-d using
viper-add-local-keys
described in the section on customization
(see Customization).
In some cases, some minor modes might override certain essential
bindings in Vi command state. This is not a big problem because this
can happen only in the beginning, when the minor mode kicks in. Typing
M-x viper-mode
will correct the situation. Viper knows about
several such minor modes and takes care of them, so the above trick
is usually not necessary. If you find that some minor mode, e.g.,
nasty-mode
interferes with Viper, putting the following in
your Viper customization file should fix the problem:
(viper-harness-minor-mode "nasty-mode")
The argument to viper-harness-minor-mode
is the name of the file for the
offending minor mode with the suffixes .el and .elc removed.
It may not be always obvious which minor mode is at fault. The only
guidance here is to look into the file that defines the minor mode you are
suspecting, say nasty-mode.el, and see if it has a variable called
nasty-mode-map
. Then check if there is a statement of the form
(define-key nasty-mode-map key function)
that binds the misbehaving
keys. If so, use the above line to harness nasty-mode
. If your
suspicion is wrong, no harm is done if you harness a minor mode that
doesn’t need to be harnessed.
It is recommended to harness even those minor modes that don’t override
Viper keys, but still have their own keymaps. A general way to
make a minor mode, my-mode
,
compatible with Viper is to have the file my-mode.el include the following code:
(when (fboundp 'viper-harness-minor-mode)
(let ((lib (file-name-sans-extension
(file-name-nondirectory load-file-name))))
(viper-harness-minor-mode lib)))
3.4 Viper Specials
Viper extends Vi with a number of useful features. This includes various
search functions, histories of search strings, Ex commands, insertions, and
Vi’s destructive commands. In addition, Viper supports file name completion
and history, completion of Ex commands and variables, and many other
features. Some of these features are explained in detail elsewhere in this
document. Other features are explained here.
(viper-buffer-search-enable)
viper-buffer-search-char nil
Enable buffer search. Explicit call to viper-buffer-search-enable
sets viper-buffer-search-char
to g. Alternatively, the user can
set viper-buffer-search-char
in his/her Viper customization file to a key
sequence to be used for buffer search. There is no need to call
viper-buffer-search-enable
in that case.
viper-toggle-search-style
This function, bound to C-c /, lets one toggle case-sensitive and
case-insensitive search, and also switch between plain vanilla search and
search via regular expressions. Without the prefix argument, the user is
asked which mode to toggle. With prefix argument 1, this toggles
case-sensitivity. With prefix argument 2, regular expression/vanilla search
will be toggled.
However, we found that the most convenient way to toggle
these options is to bind a Vi macro to
bind // to toggles case sensitivity and to /// to toggles
vanilla search. Thus, quickly hitting / twice will switch Viper from
case sensitive search to case-insensitive. Repeating this once again will
restore the original state. Likewise, quickly hitting / three times
will switch you from vanilla-style search to search via regular expressions.
If you hit something other than / after the first / or if the
second / doesn’t follow quickly enough, then Viper will issue the
usual prompt / and will wait for input, as usual in Vi.
If you don’t like this behavior, you can “unrecord” these macros in your
Viper customization file. For instance, if you don’t like the above
feature, put this in the file:
(viper-set-searchstyle-toggling-macros 'undefine)
If you don’t like this feature as a default, but would still like to have
it in some major modes, you can do so by first unsetting it globally, as
shown above, and then setting it in the desired major modes as follows:
(viper-set-searchstyle-toggling-macros nil 'c-mode)
(viper-set-searchstyle-toggling-macros nil 'lisp-mode)
Vi-isms in Emacs state
Some people find it useful to use the Vi-style search key, /, to invoke
search in modes which Viper leaves in emacs-state. These modes are:
dired-mode
, mh-folder-mode
,
Info-mode
, and Buffer-menu-mode
(more may be added in the future). So, in the above modes, Viper binds /
so that it will behave Vi-style. Furthermore, in those major modes, Viper
binds : to invoke ex-style commands, like in vi-state. And, as described
above, // and /// get bound to Vi-style macros that toggle
case-insensitivity and regexp-search.
If you don’t like these features—which I don’t really understand—you
can unbind / and : in viper-dired-modifier-map
(for
Dired) or in viper-slash-and-colon-map
, for other modes.
To unbind the macros // and /// for a major mode where you
feel they
are undesirable, execute viper-set-emacs-state-searchstyle-macros
with a
non-nil
argument. This can be done either interactively, by supplying a
prefix argument, or by placing
(viper-set-emacs-state-searchstyle-macros 'undefine)
in the hook to the major mode (e.g., dired-mode-hook
).
See Vi Macros, for more information on Vi macros.
viper-heading-start
viper-heading-end
¶
-
Regular Expressions for [[ and ]]. Note that Emacs defines
Regexps for paragraphs and sentences. See Paragraphs and
Sentences in The GNU Emacs Manual, for details.
M-x viper-set-expert-level
¶
Change your user level interactively.
viper-smart-suffix-list '("" "tex" "c" "cc" "el" "p")
¶
Viper supports Emacs-style file completion when it prompts the user for a
file name. However, in many cases, the same directory may contain files
with identical prefix but different suffixes, e.g., prog.c, prog.o,
paper.tex, paper.dvi. In such cases, completion will stop at the period.
If the above variable is a list of strings representing suffixes, Viper will
try these suffixes
in the order listed and will check if the corresponding file exists.
For instance, if completion stopped at ‘paper.’ and the user
typed RET, then Viper will check if the files paper.,
paper.tex, paper.c, etc., exist.
It will take the first such file. If no file exists, Viper will give a chance
to complete the file name by typing the appropriate suffix.
If paper. was
the intended file name, hitting return will accept it.
To turn this feature off, set the above variable to nil
.
viper-insertion-ring-size 14
¶
-
Viper remembers what was previously inserted in Insert and Replace states.
Several such recent insertions are kept in a special ring of strings of size
viper-insertion-ring-size
.
If you enter Insert or Replace state you can reinsert strings from this
ring by typing C-c M-p or C-c M-n. The former will search the
ring in
the direction of older insertions, and the latter will search in
the direction of newer insertions. Hitting C-c M-p or C-c M-n
in succession
will undo the previous insertion from the ring and insert the next item on
the ring. If a larger ring size is needed, change the value of the above
variable in the Viper customization file.
Since typing these sequences of keys may be tedious, it is suggested that the
user should bind a function key, such as f31, as follows:
(define-key viper-insert-global-user-map [f31]
'viper-insert-prev-from-insertion-ring)
This binds f31 (which is usually R11 on a Sun workstation)
to the function that inserts the previous string in the insertion history.
To rotate the history in the opposite
direction, you can either bind an unused key to
viper-insert-next-from-insertion-ring
or hit any digit (1 to 9) then
f31.
One should not bind the above functions to M-p or M-n, since
this will interfere with the minibuffer histories and, possibly, other
major modes.
viper-command-ring-size 14
¶
-
Viper keeps track of the recent history of destructive
commands, such as dw, i, etc.
In Vi state,
the most recent command can be re-executed by hitting a period, as in Vi.
However, repeated typing C-c M-p will cause Viper to show the
previous destructive commands in the minibuffer. Subsequent hitting period
will execute the command that was displayed last.
The key C-c M-n will cycle through the command history in the
opposite direction.
Since typing C-c M-p may be tedious, it is more convenient to bind an
appropriate function to an unused function key on the keyboard and use that
key. For instance, the following
(define-key viper-vi-global-user-map [f31]
'viper-prev-destructive-command)
binds the key f31 (which is usually R11 on a Sun workstation)
to the function that searches the command history in the direction of older
commands. To search in the opposite
direction, you can either bind an unused key to
viper-next-destructive-command
or hit any digit (1 to 9) then f31.
One should not bind the above functions to M-p or M-n, since
this will interfere with the minibuffer histories and, possibly, other
major modes.
viper-minibuffer-vi-face 'viper-minibuffer-vi-face
viper-minibuffer-insert-face 'viper-minibuffer-insert-face
viper-minibuffer-emacs-face 'viper-minibuffer-emacs-face
These faces control the appearance of the minibuffer text in the
corresponding Viper states. You can change the appearance of these faces
through Emacs’s customization widget, which is accessible through the
menubar.
Viper is located in this widget under the Emulations customization
subgroup of the Editing group. All Viper faces are grouped together
in Viper’s Highlighting customization subgroup.
Note that only the text you type in is affected by the above faces.
Prompts and minibuffer messages are not affected.
Purists who do not like adornments in the minibuffer can always zap them by
putting
(copy-face 'default 'viper-minibuffer-vi-face)
(copy-face 'default 'viper-minibuffer-insert-face)
(copy-face 'default 'viper-minibuffer-emacs-face)
in their Viper customization file or through the customization widget, as
described above. However, in that case, the user will not have any
indication of the current Viper state in the minibuffer. (This is important
if the user accidentally switches to another Viper state by typing ESC or
C-z).
M-x viper-go-away
¶
Make Viper disappear from the face of your running Emacs instance. If your
fingers start aching again, M-x viper-mode might save your day.
M-x toggle-viper-mode
¶
Toggle Viperization of Emacs on and off.
Viper provides some support for multi-file documents and programs.
If a document consists of several files we can designate one of them as a
master and put the following at the end of that file:
;; Local Variables:
;; eval: (viper-setup-master-buffer "file1" "file2" "file3" "file4")
;; End:
where file1
to file4
are names of files related to the master
file. Next time, when the master file is visited, the command
viper-setup-master-buffer
will be evaluated and the above files will
be associated with the master file. Then, the new Ex command
:RelatedFile (abbr. :R) will display files 1 to 4 one after
another, so you can edit them. If a file is not in any Emacs buffer, it
will be visited. The command PreviousRelatedFile (abbr., :P)
goes through the file list in the opposite direction.
These commands are akin to :n and :N, but they allow the user to
focus on relevant files only.
Note that only the master file needs to have the aforementioned block of
commands. Also, ";;" above can be replaced by some other
markers. Semicolon is good for Lisp programs, since it is considered a
comment designator there. For LaTeX, this could be "%%%", and for C the
above block should be commented out.
Even though these commands are sometimes useful, they are no substitute for
the powerful tag table facility of Emacs. Viper’s :tag command
in a primitive interface to Emacs tags. See Tags Tables in The GNU Emacs Manual, for more information on tags.
The following two commands are normally bound to a mouse click and are part
of Viper. They work only if Emacs runs as an application under X
Windows (or under some other window system for which a port of GNU Emacs 20
is available). Clicking the mouse when Emacs is invoked in an Xterm window
(using emacs -nw
) will do no good.
-
viper-mouse-search-key (meta shift 1)
¶
This variable controls the mouse-search feature of Viper. The
default value
states that holding Meta and Shift keys while clicking mouse button 1
should initiate search for a region under the mouse pointer (defined
below). This command can take a prefix argument, which indicates the
occurrence of the pattern to search for.
Note: while loading initially, Viper binds this mouse action only if it is
not already bound to something else. If you want to use the mouse-search
feature, and the Meta-Shift-mouse-1 mouse action is already bound to
something else, you can rebind the mouse-search feature by setting
viper-mouse-search-key
to something else in
your Viper customization file:
(setq viper-mouse-search-key '(meta 1))
This would bind mouse search to the action invoked by pressing the
Meta key and clicking mouse button 1. The allowed values of
viper-mouse-search-key
are lists that contain a mouse-button number
(1,2, or 3) and any combination of the words “control”, “meta”, and
“shift”.
If the requested mouse action (e.g., (meta 1)) is already taken for other
purposes then you have to confirm your intention by placing the following
command in your Viper customization file after setting
viper-mouse-search-key
:
(viper-bind-mouse-search-key 'force)
You can also change this setting interactively, through the customization
widget of Emacs (type :customize).
The region that is chosen as a pattern to search for is determined as
follows. If search is invoked via a single click, Viper chooses the region
that lies between the beginning of the “word” under the pointer (“word”
is understood in Vi sense) and the end of that word. The only difference
with Vi’s words is that in Lisp major modes ‘-’ is considered an
alphanumeric symbol. This is done for the convenience of working with Lisp
symbols, which often have an ‘-’ in them. Also, if you click on a
non-alphanumeric character that is not a word separator (in Vi sense) then
this character will also be considered alphanumeric, provided that it is
adjacent (from either side) to an alphanumeric character. This useful
feature gives added control over the patterns selected by the mouse click.
On a double-click, the region is determined by the beginning of the current
Vi’s “Word” (i.e., the largest non-separator chunk of text) and the End
of that “Word” (as determined by the E command).
On a triple-click, the region consists of the entire line where the click
occurred with all leading and trailing spaces and tabs removed.
viper-mouse-insert-key (meta shift 2)
¶
This variable controls the mouse-insert feature of Viper.
The above default value states that
holding Meta and Shift keys while clicking mouse button 2
should insert the region surrounding the
mouse pointer. The rules defining this region are the same as for
mouse-search. This command takes an optional prefix argument, which
indicates how many such regions to snarf from the buffer and insert. (In
case of a triple-click, the prefix argument is ignored.)
Note: while loading initially, Viper binds this mouse action only if it not
already bound to something else. If you want to use this feature and the
default mouse action is already bound, you can rebind mouse-insert by
placing this command in your Viper customization file:
(setq viper-mouse-insert-key '(meta 2))
If you want to bind mouse-insert to an action even if this action is
already taken for other purposes in Emacs, then you should add this command
to your Viper customization file, after setting viper-mouse-insert-key
:
(viper-bind-mouse-insert-key 'force)
This value can also be changed via the Emacs customization widget at the
menubar.
viper-multiclick-timeout
This variable controls the rate at which double-clicking must occur for the
purpose of mouse search and mouse insert. By default, this is set to
double-click-time
.
Note: The above functions search and insert in the selected window of
the latest active frame. This means that you can click in another window or
another frame and have search or insertion done in the frame and window you
just left. This lets one use these functions in a multi-frame
configuration. However, this may require some getting used to. For
instance, if you are typing in a frame, A, and then move the mouse to frame
B and click to invoke mouse search, search (or insertion) will be performed
in frame A. To perform search/insertion in frame B, you will first have to
shift focus there, which doesn’t happen until you type a character or
perform some other action in frame B—mouse search doesn’t shift focus.
If you decide that you don’t like the above feature and always want
search/insertion be performed in the frame where the click occurs, don’t
bind (and unbind, if necessary) viper-mouse-catch-frame-switch
from
the mouse event it is bound to.
Mouse search is integrated with Vi-style search, so you can
repeat it with n and N. It should be also noted that, while
case-sensitivity of search in Viper is controlled by the variable
viper-case-fold-search
, the case of mouse search is
controlled by the Emacs variable case-fold-search
, which may be set
differently from viper-case-fold-search
. Therefore, case-sensitivity
of mouse search may be different from that of the usual Vi-style search.
Finally, if the way Viper determines the word to be searched for or to be
inserted is not what you want, there is a variable,
viper-surrounding-word-function
, which can be changed to indicate
another function for snarfing words out of the buffer. The catch is that
you will then have to write such a function and make it known to your
Emacs. The function viper-surrounding-word
in viper.el can be
used as a guiding example.
3.5 Vi Macros
Viper supports much enhanced Vi-style macros and also facilitates the use
of Emacs-style macros. To define a temporary macro, it is generally more
convenient to use Emacs keyboard macro facility. Emacs keyboard macros are
usually defined anonymously, and the latest macro can be executed by typing
C-x e (or *, if Viper is in Vi state). If you need to use several
temporary macros, Viper lets you save them to a
register (a lowercase letter); such macros can then be executed by typing
@a in Vi state (if a macro was previously saved in register
a).
See Macros and Registers, for details.
If, however, you need to use a macro regularly, it must be given a
permanent name and saved. Emacs manual explains how to do this, but
invocation of named Emacs macros is quite different from Vi’s. First,
invocation of permanent Emacs macros takes time because it requires typing
too many keys (to a Vi user’s taste, anyway).
Second, binding such macros to function keys, for
fast access, hogs valuable real estate on the keyboard.
Vi-style macros are better in that respect, since Vi lets the user overload
the meaning of key sequences: keys typed in fast succession are treated
specially, if this key sequence is bound to a macro.
Viper provides Vi-style keyboard macros through the usual Ex commands,
:map and
:map!. These macros are much more powerful in Viper than
they are in the original Vi and in other emulators. This is because Viper
implements an enhanced vi-style
interface to the powerful Emacs keyboard macro facility.
First, any Emacs
command can be executed while defining a macro, not just the Vi
commands. In particular, the user can invoke Emacs commands via M-x
command-name or by pressing various function keys on the keyboard. One
can even use the mouse, although this is usually not useful and is not
recommended (and macros defined with the use of the mouse cannot be saved in
command history and in the startup file, for future use).
Macros defined by mixing Vi and Emacs commands are represented as
vectors. So, don’t be confused when you see one (usually through the
history of Ex commands). For instance, if gg is defined by typing
l, the up-arrow key and M-x next-line, its definition will look
as follows in Emacs:
[l up (meta x) n e x t - l i n e return]
Second, Viper macros are defined in a WYSIWYG style. This means that
commands are executed as you type them, so you can see precisely what is
being defined. Third, macros can be bound to arbitrary sequences of keys,
not just to printable keys. For instance, one can define a macro that will
be invoked by hitting f3 then f2 function keys. (The keys
delete and backspace are excluded; also, a macro invocation
sequence can’t start with ESC. Some other keys, such as f1 and
help, can’t be bound to macros under Emacs, since they
are bound in key-translation-map
, which overrides any other binding
the user gives to keys. In general, keys that have a binding in
key-translation-map
can’t be bound to a macro.)
Fourth, in Viper, one can define macros that are specific to a given
buffer, a given major mode, or macros that are defined for all buffers. In
fact, the same macro name can have several different definitions: one
global, several definitions for various major modes, and
definitions for various specific buffers. Buffer-specific definitions
override mode-specific definitions, which, in turn, override global
definitions.
As if all that is not enough, Viper (through its interface to Emacs
macros) lets the user define keyboard macros that ask for confirmation or
even prompt the user for input and then continue. To do this, one should
type C-x q (for confirmation) or C-u C-x q (for prompt).
For details, see Customization in The GNU Emacs
Manual.
When the user finishes defining a macro (which is done by typing C-x),
a departure from Vi), you will be asked whether you want this
macro to be global, mode-specific, or buffer-specific. You will also be
given a chance to save the macro in your Viper customization file.
This is the easiest way to save a macro and make
it permanently available. If you work your startup files with bare hands,
here is how Viper saves the above macro so that it will be
available in Viper’s Insert state (and Replace state) in buffer my-buf
only:
(viper-record-kbd-macro "gg" 'insert-state
[l up (meta x) n e x t - l i n e return]
"my-buf")
To do the same for Vi state and all buffers with the major mode
cc-mode
, use:
(viper-record-kbd-macro "gg" 'vi-state
[l up (meta x) n e x t - l i n e return]
'cc-mode)
Both macro names and macro definitions are vectors of symbols that denote
keys on the keyboard. Some keys, like \, , or digit-keys must
be escaped with a backslash. Modified keys are represented as lists. For
instance, holding Meta and Control and pressing f4 is represented as
(control meta f4).
If all members of a vectors are printable characters (or sequences, such as
\e, \t, for ESC and TAB), then they can also be represented as
strings:
(viper-record-kbd-macro "aa" 'vi-state "aaa\e" "my-buffer")
Thus, typing aa fast in Vi state will switch Viper to Insert state
(due to the first a), insert aa, and then it will switch back to Vi
state. All this will take effect only in the buffer named my-buffer
.
Note that the last argument to viper-record-kbd-macro
must be either a
string (a buffer name), a symbol representing a major mode, or t
;
the latter says that the macro is to be defined for all buffers
(which is how macros are defined in original Vi).
For convenience, Viper also lets you define Vi-style macros in its Emacs
state. There is no Ex command, like :map and :map! for doing
this, but the user can include such a macro in the Viper customization file.
The only thing is that the viper-record-kbd-macro
command should specify
emacs-state
instead of vi-state
or insert-state
.
The user can get rid of a macro either by using the Ex commands :unmap
and :unmap! or by issuing a call to viper-unrecord-kbd-macro
.
The latter is more powerful, since it can delete macros even in
emacs-state
. However, viper-unrecord-kbd-macro
is usually
needed only when the user needs to get rid of the macros that are already
predefined in Viper.
The syntax is:
(viper-unrecord-kbd-macro macro state)
The second argument must be vi-state
, insert-state
, or
emacs-state
. The first argument is a name of a macro. To avoid
mistakes in specifying names of existing macros, type M-x
viper-describe-kbd-macros and use a name from the list displayed by this
command.
If an error occurs during macro definition, Emacs
aborts the process, and it must be repeated. This is analogous to Vi,
except that in Vi the user doesn’t know there is an error until the macro is
actually run. All that means that in order for a definition to be
successful, the user must do some simple planning of the process in
advance, to avoid errors. For instance, if you want to map gg to
llll in Vi state, you must make sure that there is enough room on the
current line. Since l moves the cursor forward, it may signal an
error on reaching the end of line, which will abort the definition.
These precautions are necessary only when defining macros; they will help
avoid the need to redo the job. When macros are actually run, an error
during the execution will simply terminate the current execution
(but the macro will remain mapped).
A macro name can be a string of characters or a vector of keys.
The latter makes it possible to define macros bound to, say, double-hits
on a function key, such as up or f13.
This is very useful if you run out of function keys on your keyboard; it
makes Viper macro facility a keyboard doubler, so to speak.
Elsewhere (See Key Bindings, for details), we review
the standard Emacs mechanism for binding function keys to commands.
For instance,
(global-set-key [f13] 'repeat-complex-command)
binds the key f13 to the Emacs function that repeats the last minibuffer
command. Under Viper, however, you may still use this key for additional
purposes, if you bind, say, a double-hitting action for that key to some
other function. Emacs doesn’t allow the user to do that, but Viper does
this through its keyboard macro facility. To do this, type :map
first. When you are asked to enter a macro name, hit f13 twice, followed by
RET or SPC.
Emacs will now start the mapping process by actually executing
Vi and Emacs commands, so that you could see what will happen each time the
macro is executed. Suppose now we wanted to bind the key sequence
f13 f13 to the command eval-last-sexp
. To accomplish this, we
can type M-x eval-last-sexp followed by C-x ).
If you answer positively to Viper’s offer to save this macro in your
Viper customization file for future uses, the following will be inserted
in that file:
(viper-record-kbd-macro [f16 f16] 'vi-state
[(meta x) e v a l - l a s t - s e x p]
'lisp-interaction-mode)
To illustrate the above point, Viper provides two canned macros, which, by
default, are bound to [f12 \1] and [f12 \2] (invoked by typing
f12 then 1 and 2, respectively). These macros are useful
shortcuts to Viper’s command ring history. The first macro will execute the
second-last destructive command (the last one is executed by ., as
usual). The second macro executes the third-last command.
If you need to go deeper into the command history, you will have to use
other commands, as described earlier in this section; or you can bind,
say, f12 \3 like this:
(viper-record-kbd-macro [f12 \3] 'vi-state
[(meta x) r e p e a t - f r o m - h i s t o r y]
t)
Note that even though the macro uses the function key f12, the key is
actually free and can still be bound to some Emacs function via
define-key
or global-set-key
.
Viper allows the user to define macro names that are prefixes of other macros.
For instance, one can define [[ and [[[[ to be macros.
If you type the exact sequence of such keys and then pause, Viper will
execute the right macro. However, if you don’t pause and, say, type
[[[[text then the conflict is resolved as follows. If only one of the
key sequences, [[ or [[[[ has a definition applicable to the
current buffer, then, in fact, there is no conflict and the right macro
will be chosen. If both have applicable definitions, then the first one
found will be executed. Usually this is the macro with a shorter name. So,
in our case, [[[[text will cause the macro [[ to be executed
twice and then the remaining keys, t e x t, will be processed.
When defining macros using :map or :map!, the user enters
the actually keys to be used to invoke the macro. For instance, you
should hit the actual key f6 if it is to be part of a macro
name; you do not write f 6. When entering keys, Viper
displays them as strings or vectors (e.g., "abc"
or [f6
f7 a]
). The same holds for unmapping. Hitting TAB while
typing a macro name in the :unmap or :unmap! command will
cause name completion. Completions are displayed as strings or
vectors. However, as before, you don’t actually type ‘"’,
‘[’, or ‘]’ that appear in the completions. These are
meta-symbols that indicate whether the corresponding macro name is a
vector or a string.
One last difference from Vi: Vi-style keyboard macros cannot be defined in
terms of other Vi-style keyboard macros (but named Emacs macros are OK).
More precisely, while defining or executing a macro, the special meaning
of key sequences (as Vi macros) is ignored.
This is because it is all too easy to create an infinite loop in this way.
Since Viper macros are much more powerful than Vi’s it is impossible to
detect such loops. In practice, this is not really a limitation but,
rather, a feature.
We should also note that Vi macros are disabled in the minibuffer, which
helps keep some potential troubles away.
The rate at which the user must type keys in order for them to be
recognized as a timeout macro is controlled by the variable
viper-fast-keyseq-timeout
, which defaults to 200 milliseconds.
For the most part, Viper macros defined in the Viper customization file can
be shared between X and TTY modes.
The problem with TTY may be that the function keys there generate sequences
of events instead of a single event (as under a window system).
Emacs maps some of these sequences back to the logical keys
(e.g., the sequences generated by the arrow keys are mapped to up,
left, etc.). However, not all function keys are mapped in this way.
Macros that are bound to key sequences that contain such unmapped function
keys have to be redefined for TTY’s (and possibly for every type of TTY you
may be using). To do this, start Emacs on an appropriate TTY device and
define the macro using :map, as usual.
Finally, Viper provides a function that conveniently displays all macros
currently defined. To see all macros along with their definitions, type
M-x viper-describe-kbd-macros.
4 Commands
This section is a semi-automatically bowdlerized version of the Vi
reference created by
‘maart@cs.vu.nl’ and others. It can be
found on the Vi archives. This reference has been adapted for Viper.
4.1 Groundwork
The VI command set is based on the idea of combining motion commands
with other commands. The motion command is used as a text region
specifier for other commands.
We classify motion commands into point commands and
line commands.
The point commands are:
h, l, 0, $, w, W, b, B,
e, E, (, ), /, ?, `, f,
F, t, T, %, ;, ,, ^
The line commands are:
j, k, +, -, H, M, L, {,
}, G, ', [[, ]], []
Text Deletion Commands (see Deleting Text), Change commands
(see Changing Text), even Shell Commands (see Shell Commands)
use these commands to describe a region of text to operate on.
Viper adds two region descriptors, r and R. These describe
the Emacs regions (see Basics), but they are not movement commands.
The command description uses angle brackets ‘<>’ to indicate
metasyntactic variables, since the normal conventions of using simple
text can be confusing with Viper where the commands themselves are
characters. Watch out where < shift commands and <count> are
mentioned together!!!
‘<move>’ refers to the above movement commands, and ‘<a-z>’
refers to registers or textmarkers from ‘a’ to ‘z’. Note
that the ‘<move>’ is described by full move commands, that is to
say they will take counts, and otherwise behave like normal move commands.
‘<address>’ refers to Ex line addresses, which include
- . <No address>
Current line
- .+n .-n
Add or subtract for current line
- number
Actual line number, use .= to get the line number
- '<a-z>
Textmarker
- $
Last line
- x,y
Where x and y are one of the above
- % ¶
For the whole file, same as (1,$).
- /<pat>/
- ?<pat>?
Next or previous line with pattern <pat>.
Note that the pattern is allowed to contain newline character (inserted as
C-qC-j). Therefore, one can search for patterns that span several
lines.
Note that ‘%’ is used in Ex commands :e and :r <shell-cmd>
to mean current file. If you want a ‘%’ in your command, it must be
escaped as ‘\%’. Note that :w and the regular :r <file>
command doesn’t support the meta symbols ‘%’ and ‘#’, because
file history is a better mechanism.
Similarly, ‘#’ expands to the previous file. The previous file is
the first file in :args listing. This defaults to previous window
in the VI sense if you have one window only.
Others like ‘<args> -- arguments’, ‘<cmd> -- command’ etc.
should be fairly obvious.
Common characters referred to include:
- <sp>
Space
- <ht>
Tab
- <lf>
Linefeed
- <esc>
Escape
- <cr>
Return, Enter
We also use ‘word’ for alphanumeric/non-alphanumeric words, and
‘WORD’ for whitespace delimited words. ‘char’ refers to any
ASCII character, ‘CHAR’ to non-whitespace character.
Brackets ‘[]’ indicate optional parameters; ‘<count>’ also
optional, usually defaulting to 1. Brackets are elided for
‘<count>’ to eschew obfuscation.
Viper’s idea of Vi’s words is slightly different from Vi. First, Viper
words understand Emacs symbol tables. Therefore, all symbols declared to be
alphanumeric in a symbol table can automatically be made part of the Viper
word. This is useful when, for instance, editing text containing European,
Cyrillic, Japanese, etc., texts.
Second, Viper lets you depart from Vi’s idea of a word by changing the a
syntax preference via the customization widget (the variable
viper-syntax-preference
) or by executing
viper-set-syntax-preference
interactively.
By default, Viper syntax preference is reformed-vi
, which means that
Viper considers only those symbols to be part of a word that are specified
as word-symbols by the current Emacs syntax table (which may be different
for different major modes) plus the underscore symbol _, minus the
symbols that are not considered words in Vi (e.g., ‘,’, ‘;’,
etc.), but may be
considered as word-symbols by various Emacs major modes. Reformed-Vi works
very close to Vi, and it also recognizes words in other
alphabets. Therefore, this is the most appropriate mode for editing text
and is likely to fit all your needs.
You can also set Viper syntax preference to strict-vi
, which would
cause Viper to view all non-English letters as non-word-symbols.
You can also specify emacs
as your preference, which would
make Viper use exactly the same notion of a word as Emacs does. In
particular, the underscore may not be part of a word in some major modes.
Finally, if viper-syntax-preference
is set to extended
, Viper
words would consist of characters that are classified as alphanumeric
or as parts of symbols. This is convenient for editing programs.
viper-syntax-preference
is a local variable, so it can have different
values for different major modes. For instance, in programming modes it can
have the value extended
. In text modes where words contain special
characters, such as European (non-English) letters, Cyrillic letters, etc.,
the value can be reformed-vi
or emacs
.
If you consider using different syntactic preferences for different major
modes, you should execute, for example,
(viper-set-syntax-preference nil "extended")
in the appropriate major mode hooks.
The above discussion concerns only the movement commands. In regular
expressions, words remain the same as in Emacs. That is, the expressions
\w
, \>
, \<
, etc., use Emacs’s idea of what is a word,
and they don’t look into the value of variable
viper-syntax-preference
. This is because Viper avoids changing
syntax tables in order to not thwart the various major modes that set these
tables.
The usual Emacs convention is used to indicate Control Characters, i.e.,
C-h for Control-h. Do not confuse this with a sequence of separate
characters
C, -, h!!! The ^ is itself, never used to indicate a
Control character.
Finally, we note that Viper’s Ex-style commands can be made to work on the
current Emacs region. This is done by typing a digit argument before
:. For instance, typing 1: will prompt you with something like
:123,135, assuming that the current region starts at line 123 and
ends at line 135. There is no need to type the line numbers, since Viper
inserts them automatically in front of the Ex command.
4.2 Text Handling
4.2.1 Move Commands
- <count> h C-h
<count> chars to the left.
- <count> j <lf> C-n
<count> lines downward.
- <count> l <sp>
<count> chars to the right.
- <count> k C-p
<count> lines upward.
- <count> $
To the end of line <count> from the cursor.
- <count> ^
To the first CHAR <count> - 1 lines lower.
- <count> -
To the first CHAR <count> lines higher.
- <count> + <cr>
To the first CHAR <count> lines lower.
- 0
To the first char of the line.
- <count> |
To column <count>
- <count> f<char>
<count> <char>s to the right (find).
- <count> t<char>
Till before <count> <char>s to the right.
- <count> F<char>
<count> <char>s to the left.
- <count> T<char>
Till after <count> <char>s to the left.
- <count> ;
Repeat latest f t F T <count> times.
- <count> ,
Repeat latest f t F T
<count> times in opposite direction.
- <count> w
<count> words forward.
- <count> W
<count> WORDS forward.
- <count> b
<count> words backward.
- <count> B
<count> WORDS backward.
- <count> e
To the end of word <count> forward.
- <count> E
To the end of WORD <count> forward.
- <count> G
Go to line <count> (default end-of-file).
- <count> H
To line <count> from top of the screen (home).
- <count> L
To line <count> from bottom of the screen (last).
- M
To the middle line of the screen.
- <count> )
<count> sentences forward.
- <count> (
<count> sentences backward.
- <count> }
<count> paragraphs forward.
- <count> {
<count> paragraphs backward.
- <count> ]]
To the <count>th heading.
- <count> [[
To the <count>th previous heading.
- <count> []
To the end of <count>th heading.
- m<a-z>
Mark the cursor position with a letter.
- `<a-z>
To the mark.
- '<a-z>
To the first CHAR of the line with the mark.
- [<a-z>
Show contents of textmarker.
- ]<a-z>
Show contents of register.
- ``
To the cursor position before the latest absolute
jump (of which are examples / and G).
- ''
To the first CHAR of the line on which the cursor
was placed before the latest absolute jump.
- <count> /<string>
To the <count>th occurrence of <string>.
- <count> /<cr>
To the <count>th occurrence of <string> from previous / or ?.
- <count> ?<string>
To the <count>th previous occurrence of <string>.
- <count> ?<cr>
To the <count>th previous occurrence of <string> from previous ? or /.
- n
Repeat latest / ? (next).
- N
Repeat latest search in opposite direction.
- C-c /
Without a prefix argument, this command toggles
case-sensitive/case-insensitive search modes and plain vanilla/regular
expression search. With the prefix argument 1, i.e.,
1 C-c /, this toggles case-sensitivity; with the prefix argument 2,
toggles plain vanilla search and search using
regular expressions. See Viper Specials, for alternative ways to invoke
this function.
- %
Find the next bracket/parenthesis/brace and go to its match.
By default, Viper ignores brackets/parentheses/braces that occur inside
parentheses. You can change this by setting
viper-parse-sexp-ignore-comments
to nil
in your Viper
customization file.
This option can also be toggled interactively if you quickly hit %%%.
This latter feature is implemented as a vi-style keyboard macro. If you
don’t want this macro, put
(viper-set-parsing-style-toggling-macro 'undefine)
in your Viper customization file.
4.2.2 Marking
Emacs mark is referred to in the region specifiers r and R.
See Emacs Preliminaries, and See Basics, for explanation. Also
see Mark in The GNU Emacs manual, for an explanation of
the Emacs mark ring.
- m<a-z>
Mark the current file and position with the specified letter.
- m .
Set the Emacs mark (see Emacs Preliminaries) at point.
- m ^
Set the Emacs mark (see Emacs Preliminaries) back to where it was last
set with the m. command. This is useful when you set the mark with
m., but then some other command (such as L or G) changes
it in a way that you didn’t like.
- m <
Set the Emacs mark at beginning of buffer.
- m >
Set the Emacs mark at end of buffer.
- m ,
Jump to the Emacs mark.
- :mark <char>
Mark position with text marker named <char>. This is an Ex command.
- :k <char>
Same as :mark.
- ``
Exchange point and mark.
- ''
Exchange point and mark and go to the first CHAR on line.
- '<a-z>
Go to specified Viper mark.
- `<a-z>
Go to specified Viper mark and go to the first CHAR on line.
4.2.3 Appending Text
See Options, to see how to change tab and shiftwidth size. See the GNU
Emacs manual, or try C-ha tabs (If you have turned Emacs help on).
Check out the variable indent-tabs-mode
to put in just spaces.
Also see options for word-wrap.
- <count> a
<count> times after the cursor.
- <count> A
<count> times at the end of line.
- <count> i
<count> times before the cursor (insert).
- <count> I
<count> times before the first CHAR of the line
- <count> o
On a new line below the current (open).
The count is only useful on a slow terminal.
- <count> O
On a new line above the current.
The count is only useful on a slow terminal.
- <count> ><move>
Shift the lines described by <count><move> one
shiftwidth to the right (layout!).
- <count> >>
Shift <count> lines one shiftwidth to the right.
- <count> ["<a-z1-9>]p
Put the contents of the (default undo) buffer
<count> times after the cursor. The register will
be automatically down-cased.
- <count> ["<a-z1-9>]P
Put the contents of the (default undo) buffer
<count> times before the cursor. The register will
- [<a-z>
Show contents of textmarker.
- ]<a-z>
Show contents of register.
- <count> .
Repeat previous command <count> times. For destructive
commands as well as undo.
- f1 1 and f1 2
While . repeats the last destructive command,
these two macros repeat the second-last and the third-last destructive
commands. See Vi Macros, for more information on Vi macros.
- C-c M-p and C-c M-n
In Vi state,
these commands help peruse the history of Vi’s destructive commands.
Successive typing of C-c M-p causes Viper to search the history in
the direction
of older commands, while hitting C-c M-n does so in reverse
order. Each command in the history is displayed in the minibuffer. The
displayed command can
then be executed by typing a period.
Since typing the above sequences of keys may be tedious, the
functions doing the perusing can be bound to unused keyboard keys in the
Viper customization file. See Viper Specials, for details.
4.2.4 Editing in Insert State
Minibuffer can be edited similarly to Insert state, and you can switch
between Insert/Replace/Vi states at will.
Some users prefer plain Emacs feel in the minibuffer. To this end, set
viper-vi-style-in-minibuffer
to nil
.
- C-v
Deprive the next char of its special meaning (quoting).
- C-h
One char back.
- C-w
One word back.
- C-u
Back to the begin of the change on the
current line.
4.2.5 Deleting Text
There is one difference in text deletion that you should be
aware of. This difference comes from Emacs and was adopted in Viper
because we find it very useful. In Vi, if you delete a line, say, and then
another line, these two deletions are separated and are put back
separately if you use the ‘p’ command. In Emacs (and Viper), successive
series of deletions that are not interrupted by other commands are
lumped together, so the deleted text gets accumulated and can be put back
as one chunk. If you want to break a sequence of deletions so that the
newly deleted text could be put back separately from the previously deleted
text, you should perform a non-deleting action, e.g., move the cursor one
character in any direction.
- <count> x
Delete <count> chars under and after the cursor.
- <count> X
Delete <count> chars before the cursor.
- <count> d<move>
Delete from point to endpoint of <count><move>.
- <count> dd
Delete <count> lines.
- D
The rest of the line.
- <count> <<move>
Shift the lines described by <count><move> one
shiftwidth to the left (layout!).
- <count> <<
Shift <count> lines one shiftwidth to the left.
4.2.6 Changing Text
- <count> r<char>
Replace <count> chars by <char>; no <esc>.
- <count> R
Overwrite the rest of the line,
appending change count - 1 times.
- <count> s
Substitute <count> chars.
- <count> S
Change <count> lines.
- <count> c<move>
Change from begin to endpoint of <count><move>.
- <count> cc
Change <count> lines.
- <count> C
The rest of the line and <count> - 1 next lines.
- <count> =<move>
Reindent the region described by move.
- <count> ~
Switch lower and upper cases.
- <count> J
Join <count> lines (default 2).
- :[x,y]s/<pat>/<repl>/<f>
Substitute (on lines x through y) the pattern
<pat> (default the last pattern) with <repl>. Useful
flags <f> are ‘g’ for ‘global’ (i.e., change every
non-overlapping occurrence of <pat>) and ‘c’ for
‘confirm’ (type ‘y’ to confirm a particular
substitution, else ‘n’ ). Instead of / any
punctuation CHAR unequal to <space> <tab> and <lf> can be used as
delimiter.
In Emacs, ‘\&’ stands for the last matched expression, so
s/[ab]+/\&\&/ will double the string matched by [ab].
Viper doesn’t treat ‘&’ specially, unlike Vi: use ‘\&’ instead.
Viper does not parse search patterns and does not expand special symbols
found there (e.g., ‘~’ is not expanded to the result of the previous
substitution).
Note: The newline character (inserted as C-qC-j)
can be used in <repl>.
- :[x,y]copy [z]
Copy text between x and y to the position after z.
- :[x,y]t [z]
Same as :copy.
- :[x,y]move [z]
Move text between x and y to the position after z.
- &
Repeat latest Ex substitute command, e.g.,
:s/wrong/right.
- :x,yp
- :g/Pat/p
- :v/Pat/p
The above commands display certain buffer lines in a
temporary buffer. The first form above displays the buffer lines between
x and y. The second displays the lines of the buffer, which
match a given pattern. The third form displays the lines that do not
match the given pattern.
- #c<move>
Change upper-case characters in the region to lower-case.
- #C<move>
Change lower-case characters in the region to upper-case.
- #q<move>
Insert specified string at the beginning of each line in the region
- C-c M-p and C-c M-n
In Insert and Replace states, these keys are bound to commands that peruse
the history of the text
previously inserted in other insert or replace commands. By repeatedly typing
C-c M-p or C-c M-n, you will cause Viper to
insert these previously used strings one by one.
When a new string is inserted, the previous one is deleted.
In Vi state, these keys are bound to functions that peruse the history of
destructive Vi commands.
See Viper Specials, for details.
4.2.7 Search and Replace
See Groundwork, for Ex address syntax. See Options, to see how to
get literal (non-regular-expression) search and how to stop search from
wrapping around.
- C-c /
Toggle case-sensitive search. With prefix argument, toggle vanilla/regular
expression search.
- <count> /<string>
To the <count>th occurrence of <string>.
Viper does not parse search patterns and does not expand special symbols
found there (e.g., ‘~’ is not expanded to the result of the previous
substitution).
After typing / or ? all the usual Emacs minibuffer commands, such as
M-p and M-n are available. In addition, typing C-s will
insert the last search string used by the Emacs incremental search command
(which is bound to C-s everywhere except in this case).
- <count> ?<string>
To the <count>th previous occurrence of <string>.
- <count> g<move>
Search for the text described by move. (off by default)
- n
Repeat latest / ? (next).
- N
Idem in opposite direction.
- %
Find the next bracket and go to its match
- :[x,y]g/<string>/<cmd> ¶
Search globally [from line x to y] for <string>
and execute the Ex <cmd> on each occurrence.
- :[x,y]v/<string>/<cmd>
Execute <cmd> on the lines that don’t match.
- #g<move>
Execute the last keyboard macro for each line in the region.
See Macros and Registers, for more info.
- Q
Query Replace.
- :ta <name>
Search in the tags file where <name> is defined (file, line), and go to it.
- :[x,y]s/<pat>/<repl>/<f>
Substitute (on lines x through y) the pattern <pat> (default the last
pattern) with <repl>. Useful
flags <f> are ‘g’ for ‘global’ (i.e., change every
non-overlapping occurrence of <pat>) and ‘c’ for
‘confirm’ (type ‘y’ to confirm a particular
substitution, else ‘n’). Instead of / any
punctuation character other than <space> <tab> and <lf> can be used as
delimiter.
Note: The newline character (inserted as C-qC-j)
can be used in <repl>.
- &
Repeat latest Ex substitute command, e.g., :s/wrong/right.
- :global /<pattern>/<ex-command>
- :g /<pattern>/<ex-command>
Execute <ex-command> on all lines that match <pattern>.
- :vglobal /<pattern>/<ex-command>
- :v /<pattern>/<ex-command>
Execute <ex-command> on all lines that do not match <pattern>.
4.2.8 Yanking
- <count> y<move>
Yank from begin to endpoint of <count><move>.
- <count> "<a-z>y<move>
Yank from begin to endpoint of <count><move> to register.
- <count> "<A-Z>y<move>
Yank from begin to endpoint of <count><move> and append
to register.
- <count> yy
<count> lines.
- <count> Y
Idem (should be equivalent to y$ though).
- m<a-z>
Mark the cursor position with a letter.
- [<a-z>
Show contents of textmarker.
- ]<a-z>
Show contents of register.
- <count> ["<a-z1-9>]p
Put the contents of the (default undo) buffer
<count> times after the cursor. The register will
be automatically down-cased.
- <count> ["<a-z1-9>]P
Put the contents of the (default undo) buffer
<count> times before the cursor. The register will
4.2.9 Undoing
- u U
Undo the latest change.
- .
Repeat undo.
- :q!
Quit Vi without writing.
- :e!
Re-edit a messed-up file.
- :rec
Recover file from autosave. Viper also creates backup files
that have a ‘~’ appended to them.
4.3 Display
- C-g
At user level 1,
give file name, status, current line number
and relative position.
At user levels 2 and higher, abort the current command.
- C-c g
Give file name, status, current line number and relative position—all
user levels.
- C-l
Refresh the screen.
- <count> C-e
Expose <count> more lines at bottom, cursor stays put (if possible).
- <count> C-y
Expose <count> more lines at top, cursor stays put (if possible).
- <count> C-d
Scroll <count> lines downward (default the number of the previous scroll;
initialization: half a page).
- <count> C-u
Scroll <count> lines upward (default the number of the previous scroll;
initialization: half a page).
- <count> C-f
<count> pages forward.
- <count> C-b
<count> pages backward (in older versions C-b only works without count).
- <count> z<cr>
- zH
Put line <count> at the top of the window (default the current line).
- <count> z-
- zL
Put line <count> at the bottom of the window
(default the current line).
- <count> z.
- zM
Put line <count> in the center of the window
(default the current line).
4.4 File and Buffer Handling
In all file handling commands, space should be typed before entering the file
name. If you need to type a modifier, such as >> or !, don’t
put any space between the command and the modifier.
Note that many Ex commands, e.g., :w, accept command arguments. The
effect is that the command would start acting on the current region. For
instance, if the current region spans the lines 11 through 22, then if you
type 1:w you would see ‘:11,22w’ in the minibuffer.
- :q
Quit buffer except if modified.
- :q!
Quit buffer without checking. In Viper, these two commands
are identical. Confirmation is required if exiting modified buffers that
visit files.
- :suspend
- :stop
Suspend Viper
- :[x,y] w
Write the file. Viper makes sure that a final newline is always added to
any file where this newline is missing. This is done by setting Emacs
variable require-final-newline
to t
. If you don’t like this
feature, use setq-default
to set require-final-newline
to
nil
. This must be done in the Viper customization file.
- :[x,y] w <name>
Write to the file <name>.
- :[x,y] w>> <name>
Append the buffer to the file <name>. There should be no space between
w and >>. Type space after the >> and see what happens.
- :w! <name>
Overwrite the file <name>. In Viper, :w and :w! are identical.
Confirmation is required for writing to an existing file (if this is not
the file the buffer is visiting) or to a read-only file.
- :x,y w <name>
Write lines x through y to the file <name>.
- :wq
Write the file and kill buffer.
- :r <file> [<file> ...]
Read file into a buffer, inserting its contents after the current line.
- :xit
Same as :wq.
- :Write
- :W
Save all unsaved buffers, asking for confirmation.
- :WWrite
- :WW
Like W, but without asking for confirmation.
- ZZ
Save current buffer and kill it. If user level is 1, then save all files
and kill Emacs. Killing Emacs is the wrong way to use it, so you should
switch to higher user levels as soon as possible.
- :x [<file>]
Save and kill buffer.
- :x! [<file>]
:w![<file>] and :q.
- :pre
Preserve the file—autosave buffers.
- :rec
Recover file from autosave.
- :f [<file>]
without the argument, prints file name and character/line information afout
the currently visited file. With an argument, sets the currently visited
filename to file.
- :cd [<dir>]
Set the working directory to <dir> (default home directory).
- :pwd
Print present working directory.
- :e [+<cmd>] <files>
Edit files. If no filename is given, edit the file visited by the current
buffer. If buffer was modified or the file changed on disk, ask for
confirmation. Unlike Vi, Viper allows :e to take multiple arguments.
The first file is edited the same way as in Vi. The rest are visited
in the usual Emacs way.
- :e! [+<cmd>] <files>
Re-edit file. If no filename, re-edit current file.
In Viper, unlike Vi, e! is identical to :e. In both cases, the
user is asked to confirm if there is a danger of discarding changes to a
buffer.
- :q!
Quit Vi without writing.
- C-^
Edit the alternate (normally the previous) file.
- :rew
Obsolete
- :args
List files not shown anywhere with counts for next
- :n [count] [+<cmd>] [<files>]
Edit <count> file, or edit files. The count comes from :args.
- :N [count] [+<cmd>] [<files>]
Like :n, but the meaning of the variable
ex-cycle-other-window
is reversed.
- :b
Switch to another buffer. If ex-cycle-other-window
is t
,
switch in another window. Buffer completion is supported.
The variable viper-read-buffer-function
controls which function is
actually used to read the buffer name. The default is read-buffer
,
but better alternatives are also available in Emacs (e.g.,
ido-read-buffer
).
- :B
Like :b, but the meaning of ex-cycle-other-window
is reversed.
- :<address>r <name>
Read the file <name> into the buffer after the line <address>.
- v, V, C-v
Edit a file in current or another window, or in another frame. File name
is typed in minibuffer. File completion and history are supported.
4.5 Mapping
- :map <string>
Start defining a Vi-style keyboard macro.
For instance, typing
:map www followed by :!wc % and then typing C-x )
will cause www to run wc on
current file (Vi replaces ‘%’ with the current file name).
- C-x )
Finish defining a keyboard macro.
In Viper, this command completes the process of defining all keyboard
macros, whether they are Emacs-style or Vi-style.
This is a departure from Vi, needed to allow WYSIWYG mapping of
keyboard macros and to permit the use of function keys and arbitrary Emacs
functions in the macros.
- :unmap <string>
Deprive <string> of its mappings in Vi state.
- :map! <string>
Map a macro for Insert state.
- :unmap! <string>
Deprive <string> of its mapping in Insert state (see :unmap).
- @<a-z>
In Vi state,
execute the contents of register as a command.
- @@
In Vi state,
repeat last register command.
- @#
In Vi state,
begin keyboard macro. End with @<a-z>. This will
put the macro in the proper register. Register will
be automatically down-cased.
See Macros and Registers, for more info.
- @!<a-z>
In Vi state,
yank anonymous macro to register
- *
In Vi state,
execute anonymous macro (defined by C-x( and C-x )).
- C-x e
Like *, but works in all Viper states.
- #g<move>
Execute the last keyboard macro for each line in the region.
See Macros and Registers, for more info.
- [<a-z>
Show contents of textmarker.
- ]<a-z>
Show contents of register.
4.6 Shell Commands
The symbol ‘%’ is used in Ex shell commands to mean current file. If
you want a ‘%’ in your command, it must be escaped as ‘\%’.
However if ‘%’ is the first character, it stands as the address for
the whole file.
Similarly, ‘#’ expands to the previous file. The previous file is the
first file in :args listing. This defaults to the previous file in
the VI sense if you have one window.
Symbols ‘%’ and ‘#’ are also used in the Ex commands :e and
:r <shell-cmd>. The commands :w and the regular :r
<file> command don’t support these meta symbols, because file history is a
better mechanism.
- :sh
Execute a subshell in another window
- :[x,y]!<cmd>
Execute a shell <cmd> [on lines x through y;
% is replace by current file, \% is changed to %
- :[x,y]!! [<args>]
Repeat last shell command [and append <args>].
- :!<cmd>
Just execute command and display result in a buffer.
- :!! <args>
Repeat last shell command and append <args>
- <count> !<move><cmd>
The shell executes <cmd>, with standard
input the lines described by <count><move>,
next the standard output replaces those lines
(think of ‘cb’, ‘sort’, ‘nroff’, etc.).
- <count> !!<cmd>
Give <count> lines as standard input to the
shell <cmd>, next let the standard output
replace those lines.
- :[x,y] w !<cmd>
Let lines x to y be standard input for <cmd>
(notice the <sp> between w and !).
- :<address>r !<cmd>
Put the output of <cmd> after the line <address> (default current).
- :<address>r <name>
Read the file <name> into the buffer after the line <address> (default
current).
- :make
Run the make command in the current directory.
4.7 Options
- autoindent ¶
- ai
autoindent: In append mode after a <cr> the
cursor will move directly below the first
character on the previous line.
This setting affects the current buffer only.
- autoindent-global
- ai-global
Same as autoindent
, but affects all buffers.
- noautoindent
- noai
Cancel autoindent.
- noautoindent-global
- noai-g
Cancel autoindent-global.
- ignorecase ¶
- ic
ignorecase: No distinction between upper and lower cases when searching.
- noignorecase
- noic
Cancel ignorecase.
- magic ¶
- ma
Regular expressions used in searches; nomagic means no regexps.
- nomagic
- noma
Cancel magic.
- readonly ¶
- ro
readonly: The file is not to be changed.
If the user attempts to write to this file, confirmation will be requested.
- noreadonly
- noro
Cancel readonly.
- shell=<string> ¶
- sh=<string>
shell: The program to be used for shell escapes
(default ‘$SHELL’ (default /bin/sh)).
- shiftwidth=<count> ¶
- sw=<count>
-
shiftwidth: Gives the shiftwidth (default 8 positions).
- showmatch ¶
- sm
-
showmatch: Whenever you append a ), Vi shows
its match if it’s on the same page; also with
{ and }. If there’s no match, Vi will beep.
- noshowmatch
- nosm
Cancel showmatch.
- tabstop=<count> ¶
- ts=<count>
-
tabstop: The length of a <ht>; warning: this is
only IN the editor, outside of it <ht>s have
their normal length (default 8 positions).
This setting affects the current buffer only.
- tabstop-global
- ts-g
Same as tabstop
, but affects all buffers.
- wrapmargin=<count> ¶
- wm=<count>
-
wrapmargin: In append mode Vi automatically
puts an <lf> whenever there is an <sp> or <ht>
within <wm> columns from the right margin.
- wrapscan ¶
- ws
wrapscan: When searching, the end is
considered ‘stuck’ to the begin of the file.
- nowrapscan
- nows
Cancel wrapscan.
- :set <option>
Turn <option> on.
- :set no<option>
Turn <option> off.
- :set <option>=<value>
Set <option> to <value>.
4.9 Mouse-bound Commands
The following two mouse actions are normally bound to special search and
insert commands in of Viper:
- S-mouse-1
Holding Shift and clicking mouse button 1 will
initiate search for
a region under the mouse pointer.
This command can take a prefix argument. Note: Viper sets this
binding only if this mouse action is not
already bound to something else.
See Viper Specials, for more information.
- S-mouse-2
Holding Shift and clicking button 2 of the mouse will
insert a region surrounding the mouse pointer.
This command can also take a prefix argument.
Note: Viper sets this binding only if this mouse action is not
already bound to something else.
See Viper Specials, for more details.