= Options

== Description

Kakoune can store named and typed values that can be used both to
customize the core editor behaviour, and to store data used by extension
scripts.

[[set-option]]
Options can be modified using the `set-option` command:

--------------------------------------------
set-option [-add|-remove] <scope> <name> <values>...
--------------------------------------------

<scope> can be *global*, *buffer*, *window* or *current* (See
<<scopes#,`:doc scopes`>>). *current* relates to the narrowest scope in
which the option is already set.

Multiple <values> can be given as separate arguments when the option is a
list or map.

If `-add` or `-remove` is specified, the new value is respectively *added*
to or *removed* from the current one instead of replacing it (the exact
outcome depends on the type, see below).

[[unset-option]]
Options values can be unset in a specific scope with the `unset-option`
command:

---------------------------
unset-option <scope> <name>
---------------------------

Unsetting an option will make it fallback to the value of its parent scope,
hence options cannot be unset from the *global* scope.

[[declare-option]]
New options can be declared using the `declare-option` command:

---------------------------------------------------
declare-option [-hidden] <type> <name> [<value>...]
---------------------------------------------------

If `-hidden` is specified, the option will not be displayed in completion
suggestions.

[[update-option]]
Certain option type can be *updated*, usually to match potential changes
in the buffer they relate to. This can be triggered by the `update-option`
command:

----------------------------
update-option <scope> <name>
----------------------------

== Types

All options have a type, which defines how they are translated to/from
text and their set of valid values.

Some types are usable for user defined options while some other types
are exclusively available to built-in options.

*int*::
    an integer number.

    `set -add` performs a math addition. +
    `set -remove` performs a math substraction. +

*bool*::
    a boolean value, yes/true or no/false

*str*::
    a string, some freeform text

*regex*::
    as a string but the set commands will complain if the entered text
    is not a valid regex

*coord*::
    a line, column pair (separated by a comma)
    Cannot be used with `declare-option`

*<type>-list*::
    a list, elements are specified as separate arguments to the command.

    `set -add` appends the new element to the list. +
    `set -remove` removes each given element from the list. +

    Only `int-list` and `str-list` options can be created with
    `declare-option`.

*range-specs*::
    a timestamp (like `%val{timestamp}`,
    see <<expansions#value-expansions,`:doc expansions value-expansions`>>)
    followed by a list of range descriptors.

    Each range descriptor must use the syntax `a.b,c.d|string` or
    `a.b+length|string`, with:

        * _a_ is the line containing the first character

        * _b_ is the number of bytes from the start of the line to the
        first byte of the first character

        * _c_ is the line containing the last character

        * _d_ is the number of bytes from the start of the line to the
          first byte of the last character

        * _length_ is the length of the range in bytes, if 0 the range
          is empty, but still valid.

        * _string_ is an arbitrary string which is associated with
          the range.

    All numeric fields are 1-based.

    When the command `update-option` is used on an option of this type,
    its ranges get updated according to all the buffer modifications
    that happened since its timestamp.

    `set -add` appends the new pairs to the list. +
    `set -remove` removes the given pairs from the list. +

    See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)

*line-specs*::
    a list of a line number and a corresponding flag (`<line>|<flag
    text>`), except for the first element which is just the timestamp
    of the buffer. When `update-option` is used on an option of this
    type, its lines get updated according to all the buffer modifications
    that happened since its timestamp.
    See <<highlighters#specs-highlighters,`:doc highlighters specs-highlighters`>>)

    `set -add` appends the new specs to the list. +
    `set -remove` removes the given specs from the list. +

*completions*::
    a list of `<text>|<select cmd>|<menu text>` candidates,
    except for the first element which follows the
    `<line>.<column>[+<length>]@<timestamp>` format to define where the
    completion apply in the buffer.

    Select commands are arbitrary Kakoune commands that will be executed
    each time the element is selected in the menu. The common use case is
    to display element specific documentation.

    Markup can be used in the menu text.
    (see <<faces#markup-strings,`:doc faces markup-strings`>>)

    `set -add` adds given completions to the list. +
    `set -remove` removes given completions from the list. +

*enum(value1|value2|...)*::
    an enum, taking one of the given values
    Cannot be used with `declare-option`

*flags(value1|value2|...)*::
    a set of flags, taking a combination of the given values joined by a
    '|' character.

    `set -add` adds the given flags to the combination. +
    `set -remove` removes the given flags to the combination. +

    Cannot be used with `declare-option`

*<type>-to-<type>-map*::
    a list of `key=value` pairs.

    `set -add` adds the given pair to the hashmap or replace an already
    existing key. +
    `set -remove` removes the given pair from the hashmap, if only the
    key is provided it removes that entry regardless of the associated
    value. +

    Only `str-to-str-map` options can be created with `declare-option`.

== Builtin options

*tabstop* `int`::
    _default_ 8 +
    width of a tab character

*indentwidth* `int`::
    _default_ 4 +
    width (in spaces) used for indentation, 0 means a tab character

*scrolloff* `coord`::
    _default_ 0,0 +
    number of lines, columns to keep visible around the cursor when
    scrolling

*eolformat* `enum(lf|crlf)`::
    _default_ lf +
    the format of end of lines when writing a buffer, this is autodetected
    on load; values of this option assigned to the `window` scope are
    ignored

*BOM* `enum(none|utf8)`::
    _default_ none +
    define if the file should be written with a unicode byte order mark;
    values of this option assigned to the `window` scope are ignored

*readonly* `bool`::
    _default_ false +
    prevent modifications from being saved to disk, all buffers if set
    to `true` in the `global` scope, or current buffer if set in the
    `buffer` scope; values of this option assigned to the `window`
    scope are ignored

*incsearch* `bool`::
    _default_ true +
    execute search as it is typed

*aligntab* `bool`::
    _default_ false +
    use tabs for alignment command

*autoinfo* `flags(command|onkey|normal)`::
    _default_ command|onkey +
    display automatic information box in the enabled contexts

*autocomplete* `flags(insert|prompt)`::
    _default_ insert|prompt +
    automatically display possible completions in the enabled modes.

*ignored_files* `regex`::
    filenames matching this regex won't be considered as candidates
    on filename completion (except if the text being completed already
    matches it)

*disabled_hooks* `regex`::
    hooks whose group matches this regex won't be executed. For example
    indentation hooks can be disabled with `.*-indent`.
    (See <<hooks#disabling-hooks,`:doc hooks`>>)

*filetype* `str`::
    arbitrary string defining the type of the file. Filetype dependent
    actions should hook on this option changing for activation/deactivation

*path* `str-list`::
    _default_ ./ %/ /usr/include +
    directories to search for *gf* command and filenames completion
    `%/` represents the current buffer directory

*completers* `completer-list`::
    _default_ filename word=all +
    completion engines to use for insert mode completion (they are tried
    in order until one generates candidates). Existing completers are:

    *word=all*, *word=buffer*:::
        which complete using words in all buffers (*word=all*)
        or only the current one (*word=buffer*)

    *filename*:::
        which tries to detect when a filename is being entered and
        provides completion based on local filesystem

    *line=all*, *line=buffer*:::
        which complete using lines in all buffers (*line=all*)
        or only the current one (*line=buffer*)

    *option=<opt-name>*:::
        where *opt-name* is an option of type 'completions' whose
        contents will be used

*static_words* `str-list`::
    list of words that are always added to completion candidates
    when completing words in insert mode

*extra_word_chars* `codepoint-list`::
    a list of all additional codepoints that should be considered
    as word character. This must be set on the buffer, not the window,
    for word completion to offer words containing these codepoints.

*matching_pairs* `codepoint-list`::
    _default_ ( ) { } [ ] < > +
    a list of codepoints that are to be treated as matching pairs
    for the *m* command.

*autoreload* `enum(yes|no|ask)`::
    _default_ ask +
    auto reload the buffers when an external modification is detected

*writemethod* `enum(overwrite|replace)`::
    _default_ overwrite +
    method used to write buffers to file, `overwrite` will open the
    existing file and write on top of the previous data, `replace`
    will open a temporary file next to the target file, write it and
    then rename it to the target file.

*debug* `flags(hooks|shell|profile|keys|commands)`::
    dump various debug information in the '\*debug*' buffer

*idle_timeout* `int`::
    _default_ 50 +
    timeout, in milliseconds, with no user input that will trigger the
    *PromptIdle*, *InsertIdle* and *NormalIdle* hooks, and autocompletion.

*fs_check_timeout* `int`::
    _default_ 500 +
    timeout, in milliseconds, between checks in normal mode of modifications
    of the file associated with the current buffer on the filesystem.

*modelinefmt* `string`::
    A format string used to generate the mode line, that string is
    first expanded as a command line would be (expanding '%...{...}'
    strings), then markup tags are applied (see
    <<faces#markup-strings,`:doc faces markup-strings`>>)
    Two special atoms are available as markup:

        *`{{mode_info}}`*:::
            Information about the current mode, such as `insert 3 sel` or
            `prompt`. The faces used are StatusLineMode, StatusLineInfo,
            and StatusLineValue.

        *`{{context_info}}`*:::
            Information such as `[+][recording (@)][no-hooks][new file][fifo]`,
            in face Information.

    The default value is '%val{bufname} %val{cursor_line}:%val{cursor_char_column} {{context_info}} {{mode_info}} - %val{client}@[%val{session}]'

*ui_options* `str-to-str-map`::
    a list of `key=value` pairs that are forwarded to the user
    interface implementation. The NCurses UI support the following options:

        *ncurses_set_title*:::
            if *yes* or *true*, the terminal emulator title will
            be changed

        *ncurses_status_on_top*:::
            if *yes*, or *true* the status line will be placed
            at the top of the terminal rather than at the bottom

        *ncurses_assistant*:::
            specify the nice assistant displayed in info boxes,
            can be *clippy* (the default), *cat*, *dilbert* or *none*

        *ncurses_enable_mouse*:::
            boolean option that enables mouse support

        *ncurses_change_colors*:::
            boolean option that can disable color palette changing if the
            terminfo enables it but the terminal does not support it.

        *ncurses_wheel_down_button*, *ncurses_wheel_up_button*:::
            specify which button send for wheel down/up events

        *ncurses_shift_function_key*:::
            Function key from which shifted function key start, if the
            terminal sends F13 for <s-F1>, this should be set to 12.

[[startup-info]]
*startup_info_version* `int`::
    _default_ 0 +
    Controls which messages will be displayed in the startup info box, only messages
    relating to a Kakoune version greater than this value will be displayed. Versions
    are written as a single number: Like `20180413` for version `2018.04.13`

== Current values

The current value for an option can be viewed using
<<expansions#option-expansions, `:doc expansions option-expansions`>>.

For example, the current value of the `BOM` option can be displayed in the
status line using the `echo` command:

--------------
echo %opt{BOM}
--------------

The current values for all options can be dumped to the *\*debug*\* buffer using
the following command:

-------------
debug options
-------------