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= FAQ

== The project

=== How to pronounce the name of the project and what does it mean ?

The name of the project is pronounced "Kak-oon", and is a word taken from a
New Caledonian dialect based on French. It means a hard blow, usually a punch,
but generally refers to a blow into which all of one's strength went.

=== Is there going to be a Windows port of Kakoune ?

As many features provided by UNIX systems would be missing, or if anything
much less efficient on a Windows system, the incentive to porting the
project to this operating system is pretty low.

Moreover, you can get pretty decent performance by using Kakoune on Cygwin
(which is officially supported).

== Interfacing

=== Can I use Kakoune as a pager ?

Kakoune can be used as a pager, either by setting the `PAGER` environment
variable to `kak`, or by writing data directly to its standard input using a
shell pipeline.

=== Are there any non-console based frontends available ?

No graphical frontend is currently officially maintained, you can however
try experimental community-developed ones.

=== Why are colors misrendered in my Kakoune clients ?

The most probable cause for that is a very widespread practice that consists
in setting the `TERM` environment variable in the shell's configuration file.
This variable should be set by the terminal emulator, and not overridden with
an arbitrary value, otherwise it might interfere with general UI rendering on
the terminal's window.

=== I'm using `tmux` and colors look weird

If you're using a tool that doesn't support "palette switching", colors will
still be slightly off: they are being rounded down to values supported by the
regular color palette by Kakoune. Fortunately, on recent versions of `tmux`
(>=2.6), you can work around that by using the following configuration
settings:

.~/.tmux.conf
----
set -g default-terminal "tmux-256color"
set -ga terminal-overrides ",*col*:Tc"
----

Note: `\*col*` is a regular expression that matches your terminal's `$TERM`
value, modify it if necessary, e.g. `xterm-termite`.

Next, run the following command to create a local `terminfo` override:

----
$ tic /path/to/kakoune/contrib/tmux-256color.terminfo
----

Finally, quit all existing sessions (`tmux kill-server`), and restart `tmux`.

=== Why do I see weird special characters (~T~@~U) around Clippy?

You need a UTF-8 compliant locale, in order to render special characters.

The way to do so might vary from distribution to another, but an easy way
to verify that your locale is set correctly is to run the following command:

----
$ locale
----

The output should look similar to the following (with eventually another
language set instead of `en_US`):

----
LANG=en_US.UTF-8
LC_CTYPE="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_PAPER="en_US.UTF-8"
LC_NAME="en_US.UTF-8"
LC_ADDRESS="en_US.UTF-8"
LC_TELEPHONE="en_US.UTF-8"
LC_MEASUREMENT="en_US.UTF-8"
LC_IDENTIFICATION="en_US.UTF-8"
LC_ALL=
----

You can also run the project's test suite, which should display errors if
your locale doesn't support UTF-8 rendering:

----
$ cd kakoune
$ make test
----

=== Why does leaving insert mode take more than half a second in `tmux` ?

Upon hitting the escape key, `tmux` waits for a short period of time to
determine whether it's part of a function or a meta key sequence. In order
to fix this "lag", set the waiting period in your `tmux` configuration file
to a short time, e.g. 25ms: `set -sg escape-time 25`

=== Can I split the window to display different buffers in them ?

As a fairly compliant follower of the UNIX philosophy, Kakoune does not
try to implement features that are best handled by separate, dedicated
tools. Window splitting in terminals is a prime example of that
concept, where the editor provides commands to interact with several
terminal multiplexers (e.g. `tmux`), as opposed to emulating their
functionalities.

In order to open buffers in the same window simultaneously using `tmux`
(or one of the supported multiplexers), run Kakoune in a `tmux` session,
and simply use the `:new` command to spawn new clients as you would
have otherwise in an X11 environment.

== Generic functionalities

=== Something is wrong, how can I get more debug information?

You can get quite a lot of information out of the editor at runtime. One
way is through the `:debug` command, which will print out statistics and
state data into the `\*debug*` buffer:

----
:debug <command>
----

Another way is to set flags on the `debug` option:

----
:set global debug <flags>
----

Make sure to read all possible values suggested by the completion engine,
as you type out both commands in a prompt.

If you want to troubleshoot a crash, you need to compile the editor with
debug symbols enabled:

----
$ make debug=yes
----

The resulting binary should produce a stacktrace that you can, afterwards,
post in an issue in unmangled form (c.f. `c++filt`).

=== How can I explore the filesystem the way Vim's NerdTree does ?

The builtin file completion engine used when opening a file for editing
(using the `:edit` command and letting the suggestions popup in the menu
beneath) is much more convenient than Vim's, which should suit basic needs.

However, if you need an actual explorer to interact with the editor,
you can create a Kakoune script that will spawn the tool in question,
which should in return send an "edit" command followed by the path of the
file you selected to the current Kakoune session (e.g. `echo "eval -client
$kak_client edit /path/to/file" | kak -p $kak_session`).

=== How do I automatically indent code, as Vim does with `=` ?

As `Kakoune` doesn't parse the contents of the buffers, there is no builtin
equivalent for this Vim feature. Use a formatter/prettifier dedicated to
the language you're using with the help of the `|` key.

Example: `%|indent<ret>` to indent an entire buffer with C code.

Note that you can also set the `formatcmd` option, used by the `format`
command to handle formatting in the current buffer without further
interaction.

=== Can Kakoune automatically complete the parameters of my functions ?

As mentioned in the above question about Vim's `=` key, Kakoune does not
parse the contents of a buffer by itself, which makes it impossible for
the editor to propose candidates upon completion.

However, support for such a feature can be achieved through the use of a
dedicated tool, as is the case with `clang` and C code: you can use the
`clang-enable-autocomplete` and `clang-complete` builtin commands whenever
editing a C/C++ file, and completion will work on function parameters.

Other language-support scripts implement this functionality in a similar way,
for example the `jedi` script for Python buffers.

Another way to get automatic parameter completion that doesn't depend on
built-in support in Kakoune is through the
https://microsoft.github.io/language-server-protocol/[Language Server Protocol],
for which you can find implementations that interact with the editor.

=== Why aren't widely known command line shortcuts such as <c-w> or <c-u> available in Kakoune ?

Despite their widespread availability in multiple tools, those shortcuts do
not fit the paradigm that Kakoune implements, which is based on selections
first.

However, you can easily declare key mappings in your configuration file
to be able to use those control-based shortcuts in insert mode.
(See <<mapping#,`:doc mapping`>>)

Also note that a subset of "readline shortcuts" is implemented for command
prompts.

=== Can I disable auto-indentation completely ?

All the indentation hooks are conventionally named `<lang>-indent`, which
allows us to use the `disabled_hooks` variable to disable indentation
globally with the following command: `set global disabled_hooks '.+-indent'`

=== How to enable syntax highlighting ?

The mimetype of the files opened in new buffers is detected using the
`file` command, and syntax highlighting enabled automatically when
possible.

=== My file seems to be highlighted with the wrong colors, I thought syntax highlighting was detected automatically ?

The `file` utility has several shortcomings, such as detecting the
wrong mimetype for a file containing data with different syntax, e.g.
a Python script containing hardcoded HTML templates detected as an HTML
file.

Kakoune does its best at detecting file types (using known extensions
for a given format for instance), but not much can be done about those
ambiguous cases. You might consider writing a custom `$HOME/.magic` file
if needed.

=== Can I disable syntax highlighting completely ?

Similarly to the indentation hooks, the name format followed by the
highlighting hooks is `<lang>-highlight`. You can thus disable syntax
highlighting using the following command: `set global disabled_hooks
'.+-highlight'`

== The editing language

=== Why aren't there other scopes similar to `%sh{}` e.g. python ?

Supporting custom scopes would add hard dependencies to the project, which
is too much of a drawback when balanced against the low cost of using
an interpreter in a regular shell scope (e.g. `%sh{ python -c "..." }`).
The shell scope allows users to spawn any interpreter they want, for a minimal
cost in terms of performance, it is therefore the reason why it's the only
one available by default.

=== What shell is used to expand `%sh{}` scopes ?

The server expands shell scopes using the `sh` binary, stored in one of the
directories where all the POSIX standard utilities can be found -this list
of directories is stored in a system configuration variable, and queried
by Kakoune at startup.

In most distributions, `/bin/sh` will end up being used.

=== Why does a dot `.` in a regex select newline characters ?

Data in buffers is a stream of characters, and newlines do not receive special
treatment compared to other characters, with regards to regex matching. In
order to select data in a line without any trailing newline characters, one could
use the `[^\n]+` pattern, which is arguably a good compromise when
balanced against the ability to select data over several lines.

You can instruct the regex engine to stop matching newline characters with
`.` by disabling the appropriate flag (`(?S)`).

=== Why does `a` extend the current selection, but `i` leaves it untouched ?

Selections are ranges of characters whose delimiters are an "anchor" and
a "cursor", and inserting characters is always done before the cursor in
insert mode.

Consequently, using the append primitive (`a`) nudges the cursor forward to
make room for characters, effectively extending the current selection since
the anchor remains immobile, even when the anchor and the cursor are at the
same location. By opposition, using the insert primitive (`i`) merely adds
characters before the cursor, which never modifies the current selection.