viper: Viper Specials
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’). 
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. Paragraphs and
Sentences (emacs)Paragraphs, 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.
(emacs)Tags Tables, 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’ in Emacs and to
‘mouse-track-multi-click-time’ milliseconds in XEmacs.
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.
Info Catalog
viper: Packages that Change Keymaps
viper: Customization
viper: Vi Macros