= Hooks

== Description

Commands can be registered to be executed when certain events arise. To
register a hook use the following command:

----------------------------------------------------------------------
hook [-group <group>] <scope> <hook_name> <filtering_regex> <commands>
----------------------------------------------------------------------

*scope* can be one of *global*, *buffer* or *window* (See
<<scopes#,`:doc scopes`>>).

*command* is a string containing the commands to execute when the hook
is called.

For example to automatically use line numbering with .cc files, use the
following command:

--------------------------------------------------------------
hook global WinCreate .*\.cc %{ add-highlighter number-lines }
--------------------------------------------------------------

If *group* is given, make this hook part of the named group. Groups are used
for removing hooks with the following command:

----------------------------
remove-hooks <scope> <group>
----------------------------

A call to the command above will remove every hooks in *scope* that are part
of the given *group*.

Hooks declared with the `-once` switch are automatically removed after running.

== Default hooks

*NormalIdle*::
    a certain duration has passed since last key was pressed in normal mode

*NormalBegin*::
    entering normal mode

*NormalEnd*::
    leaving normal mode

*NormalKey* `key`::
    a key is received in normal mode

*InsertIdle*::
    a certain duration has passed since last key was pressed in insert mode

*InsertBegin*::
    entering insert mode

*InsertEnd*::
    leaving insert mode

*InsertKey* `key`::
    a key is received in insert mode

*InsertChar* `char`::
    a character is received in insert mode

*InsertDelete* `deleted char`::
    a character is deleted in insert mode

*InsertMove* `move key`::
    the cursor moved (without inserting) in insert mode

*PromptIdle*::
    a certain duration has passed since last key was pressed in prompt mode

*WinCreate* `buffer name`::
    a window was created

*WinClose* `buffer name`::
    a window was destroyed

*WinResize* `<line>.<column>`::
    a window was resized

*WinDisplay* `buffer name`::
    a window was bound a client

*WinSetOption* `<option_name>=<new_value>`::
    an option was set in a window context

*GlobalSetOption* `<option_name>=<new_value>`::
    an option was set at the global scope

*BufSetOption* `<option_name>=<new_value>`::
    an option was set in a buffer context

*BufNewFile* `filename`::
    a buffer for a new file has been created

*BufOpenFile* `filename`::
    a buffer for an existing file has been created

*BufCreate* `filename`::
    a buffer has been created

*BufWritePre* `filename`::
    executed just before a buffer is written

*BufWritePost* `filename`::
    executed just after a buffer is written

*BufReload* `filename`::
    executed after a buffer reload has been triggered by an external
    modification to its file

*BufClose* `buffer name`::
    executed when a buffer is deleted, while it is still valid

*BufOpenFifo* `buffer name`::
    executed when a buffer opens a fifo

*BufReadFifo* `buffer name`::
    executed after some data has been read from a fifo and inserted in
    the buffer

*BufCloseFifo*::
    executed when a fifo buffer closes its fifo file descriptor either
    because the buffer is being deleted or the writing end has been closed

*RuntimeError* `error message`::
    an error was encountered while executing a user command

*ModeChange* `<old mode>:<new mode>`::
    Triggered whenever the current input mode changes

*KakBegin* `session name`::
    kakoune has started, this hook is called just after reading the user
    configuration files

*KakEnd*::
    kakoune is quitting

*FocusIn* `client name`::
    on supported clients, triggered when the client gets focused

*FocusOut* `client name`::
    on supported clients, triggered when the client gets unfocused

*InsertCompletionShow*::
    Triggered when the insert completion menu gets displayed

*InsertCompletionHide*::
    Triggered when the insert completion menu gets hidden

*InsertCompletionSelect* `selected completion`::
    Triggered when an entry is selected in the insert completion
    menu. The filtering text is the selected completion text or
    the empty string if the original text was selected back

*RawKey* `key`::
    Triggered whenever a key is pressed by the user

When not specified, the filtering text is an empty string. Note that
some hooks will not consider underlying scopes depending on what context
they are bound to be run into, e.g. the `BufWritePost` hook is a buffer
hook, and will not consider the `window` scope.

While defining hook commands with a `%sh{}` block, some additional env
vars are available:

* `kak_hook_param`: filtering text passed to the currently executing hook

* `kak_hook_param_capture_N`: text captured by the hook filter regex capture N

== Disabling Hooks

Any normal mode command can be prefixed with `\ ` which will disable hook
execution for the duration for the command (including the duration of modes
the command could move to, so `\i` will disable hooks for the whole insert
session).

As autoindentation is implemented in terms of hooks, this can be used to
disable it when pasting text.

A less temporary alternative is to set the `disabled_hooks` option which
accepts a regex describing which hooks won't be executed.
For example indentation hooks can be disabled with '.*-indent'.

Finally, hook execution can be disabled while using the `execute-keys` or
`evaluate-commands` commands by using the `-no-hooks` switch.
(See <<execeval#,`:doc execeval`>>)

As an exception to these rules, hooks declared with the `-always` switch
are triggered no matter what. A good use case is doing some cleanup on `BufCloseFifo`.
