VI Mode


Introduction

Vim Logo Kate’s VI mode is a project to bring Vim-like, modal editing to the Kate text editor and by extension to other KDE programs who share the same editor component. The project started as a Google Summer of Code project in 2008 – where all the basic functionality was written. I have continued to maintain and further develop this code and the number of missing features from Vim are slowly decreasing. Most Vim users will already be productive in Kate’s VI mode. A list of what’s missing is found at the bottom of the page.

This page is meant to be an updated overview of this work.

To enable the VI input mode, go to
Settings → Configure Kate… → Editing → VI Input Mode.
It can also be toggled with the “VI Input Mode” setting in the “Edit” menu. (The default shortcut key is Meta+Ctrl+V – where Meta usually is the Windows key).

Goals

The goal of the VI mode is not to be a complete replacement for Vim and support all Vim’s features. Its aim is to make the “Vim way” of text editing – and the Vim habits learned – available for programs using the Kate text editor as their internal editor. These programs include

  1. The Kate Text editor
  2. KWrite – KDE’s simple text editor
  3. KDevelop – An advanced IDE for many programming languages
  4. Kile – A LaTeX editor

The VI mode aims integrate nicely with the programs and deviate from Vim’s behaviour where it makes sense. For example, :w will open a save dialogue in Kate’s VI mode.

Incompatibilities with Vim

There are only a few features of Kate’s VI mode which are incompatible with Vim (not counting things missing). They are listed below together with the respective reasons.

  1. Kate: U and ctrl+r is redo Vim: ctrl+r is normal redo, U is used to undo all latest changes on one line The reason for having U act as redo in Kate’s VI mode is that the shortcut ctrl+r by default is taken by Kate’s replace function (search and replace). By default, the VI mode won’t override Kate’s shortcuts (this can be configured in Settings → Configure Kate… → Editing → Vi Input Mode), therefore a redo-action needs to be available as a “regular” key press, too. Besides, the behaviour of the U command in Vim doesn’t map well to Kate’s internal undo system, so it would be non-trivial to support anyway.
  2. Kate: :print shows the ‘print’ dialogue Vim: :print prints the lines of the given range like its grandfather ed Commands like :print are available not only in the VI mode but for users using “regular” Kate, too – I have therefore chosen to let the :print command open the print dialogue – following the principle of least surprise instead of mimicking Vim’s behaviour.
  3. Kate: ‘Y’ yanks to end of line. Vim: ‘Y’ yanks whole line, just like ‘yy’. VI’s behaviour for the ‘Y’ command is in practice a bug; For both change and delete commands, ‘cc’/’dd’ will do its action on the current line and ‘C’/’D’ will work from the cursor column to the end of the line. However, both ‘yy’ and ‘Y’ yanks the current line.In Kate’s VI Mode ‘Y’ will yank to the end of the line. This is described as “more logical” in the Vim documentation.
  4. Kate: :map alters the selected lines of the document using the provided Javascript expression. Vim: :map adds the provided mapping to Normal and Visual modes. The “map” command was already reserved by Kate; in 4.12+, you can use a combination of :nmap and :vmap to replace it.

Supported Commands

Supported normal/visual mode commands

aEnter Insert Mode and append
AEnter Insert Mode and append to EOL
iEnter Insert Mode
IInsert before first non-blank char in line
vEnter Visual Mode
VEnter Visual Line Mode
Enter Visual Block Mode
gvRe-select Visual
oOpen new line under
OOpen new line over
JJoin lines
cChange
CChange to EOL
ccChange line
sSubstitute char
SSubstitute line
ddDelete line
dDelete
DDelete to EOL
xDelete char
XDelete char backward
guMake lowercase
guuMake lowercase line
gUMake uppercase
gUUMake uppercase line
yYank
yyYank line
YYank to EOL
pPaste
PPaste before
r.Replace character
REnter replace mode
:Switch to command line
/Search
uUndo
Redo
URedo
m.Set mark
>>Indent line
<<Unindent line
>Indent lines
<Unindent lines
Scroll page down
Scroll page down
Scroll page up
Scroll page up
Scroll half page up
Scroll half page down
zzCentre view on cursor
gaPrint character code
.Repeat last change
==Align line
=Align lines
~Change case
Add to number
Subtract from number
Go to prev jump
Go to next jump
hSwitch to left view
Switch to left view
Switch to left view
jSwitch to down view
Switch to down view
Switch to down view
kSwitch to up view
Switch to up view
Switch to up view
lSwitch to right view
Switch to right view
Switch to right view
wSwitch to next view
Switch to next view
sSplit horizontally
SSplit horizontally
Split horizontally
vSplit vertically
Split vertically
gtSwitch to next tab
gTSwitch to prev tab
gqqFormat line
gqFormat lines
q. / qBegin/ finish recording macro using the named macro register.

Supported motions

hLeft
Left
Left
jDown
Down
Down to first non blank
kUp
Up
Up to first non blank
lRight
Right
Right
$To EOL
To EOL
To 0 column
To 0 column
^To first character of line
f.Find char
F.Find char backward
t.To char
T.To char backward
;Repeat last t. or f. command
,Repeat last t. or f. command
nFind next
NFind prev
ggTo first line
GTo last line
wWord forward
WWORD forward
bWord backward
BWORD backward
eTo end of word
ETo end of WORD
geTo end of prev word
gETo end of prev WORD
|To screen column
%To matching item
`[a-zA-Z><]To mark
‘[a-zA-Z><]To mark line
[[To previous brace block start
]]To next brace block start
[]To previous brace block end
][To next brace block end
*To next occurrence of word under cursor
#To prev occurrence of word under cursor
HTo first line of window
MTo middle line of window
LTo last line of window
gjTo next visual line
gkTo prev visual line

Supported text objects

iwInner word
awA word
iWInner WORD
aWA WORD
i”Inner double quote
a”A double quote
i’Inner single quote
a’A single quote
i`Inner back quote
a`A back quote
ibInner paren
i)Inner paren
i(Inner paren
abA paren
a)A paren
a(A paren
iBInner curly bracket
o}Inner curly bracket
i{Inner curly bracket
aBA curly bracket
a}A curly bracket
a{A curly bracket
i<Inner inequality sign
i>Inner inequality sign
a<A inequality sign
a>A inequality sign
i[Inner bracket
I]Inner bracket
a[A bracket
a]A bracket
i,Inner comma
a,A comma

Supported insert mode commands

Unindent
Indent
Insert from below
Insert from above
Delete word
.Insert content of register
Switch to normal mode for one command
Increase number under cursor
Decrease number under cursor

The Comma Text Object

This is something that I have been missing in Vim. The comma text object makes it easy to modify parameter lists in C-like languages and other comma separated lists. It is basically the area between two commas or between a comma and a bracket. In the line shown in the illustration to the right, the three ranges this text object can span are highlighted in red.

Comma text object ranges. If the cursor is over, say, “arg2”, pressing c i , (“change inner comma”) would delete “double arg2” and place the cursor between the two commas in insert mode. A very convenient way to change a function’s parameters.

Emulated Vim Command Bar

Kate 4.11 introduced a hidden config option that make “/”, “?” and “:” bring up a new search/ command in place of the usual Kate Find/ Replace / Command-line bar. The bar is intended to intended to replicate many of the features of Vim’s command bar, and also to fix many of the issues with Kate Vim mode’s interaction with Kate’s Find/ Replace bar (interactive replace not working; incremental search not positioning the cursor correctly; not usable in mappings/ macros; etc).

The following shortcuts are provided by the emulated command bar; as with Vim, these can be remapped with cmap, cnoremap, etc:

.insert contents of register.
Insert word under the (document) cursor.
Invoke context-specific completion (see below)/ move back/ up in the completion list.
Move forward/ down in the completion list.
Kate Vim Extension. Auto-complete word from document.
Kate Vim Extension. In a sed-replace expression (i.e. one of the form s/find/replace/[g][c][i]), clear the “find” term and place the cursor there.
Kate Vim Extension. In a sed-replace expression (i.e. one of the form s/find/replace/[g][c][i]), clear the “replace” term and place the cursor there.
.Kate Vim Extension. As with ., insert the content of the named register, but escape it in such a way that when used with a search, we search for the literal content of the register; not the content of the register interpreted as a regex.

The “context-specific completion” is decided as follows:

  • In a search bar (“/” or “?”), auto-complete from search history (which includes searches initiated via “*” and “#”; searches done in sed-replace expressions; etc.)
  • In an empty command bar (“:”), auto-complete from command history (NB: auto-completion of command names is invoked automatically when you begin typing).
  • In a command-bar containing a sed-replace expression (e.g. “‘<,’>s/find/replace/gc”), if the cursor is positioned over “find”, auto-complete from the “search” history; if over the “replace”, auto-complete from the history of “replace” terms.

When executing a sed-replace expression in the command bar with the “c” flag (e.g. s/find/replace/gc), a Vim-style interactive search/replace expression will be initiated.

Some example usages of the emulated command bar, with GIF animations, are given in this blog. In 4.11, the emulated command bar can be enabled by setting the hidden config option “Vi Input Mode Emulate Command Bar” to “true”. in your katerc/ kwriterc/ kdeveloprc.

Missing Features

As stated earlier, the goal of Kate’s VI Mode is not to support 100% of Vim’s features, however, there are some features which are sorely missed

  • Visual block mode – especially the ability to prepend/append text to the visual block selection.
  • Having ex commands available in other programs than the Kate application.
  • The search code needs improvement and the * and # commands should just be regular searches.

If you miss other features or want to help on the ones mentioned above, feel free to contact me or send patches! :-)

Change Log

  • 2010-05-16:
    Initial version. Collected the information from blog entries and README files to make a single source of current information.
  • 2010-05-17:
    Ctrl+A and Ctrl+X added (increment/decrement number under cursor).
  • 2010-08-30:
    Moved page to kate-editor.org.
  • 2010-09-10:
    Fixed the text on the comma text object and made some formatting fixes