mirror of
https://github.com/mawww/kakoune.git
synced 2024-12-29 14:44:56 +03:00
151 lines
4.7 KiB
Plaintext
151 lines
4.7 KiB
Plaintext
Writing kak scripts
|
|
===================
|
|
|
|
Interaction with external tools from a Kakoune session is supported
|
|
through the use of scripts. Once loaded by the editor (either
|
|
automatically or manually), they allow extending the functionalities
|
|
provided by default through commands and hooks.
|
|
|
|
Their implementation should be kept as simple as possible, as they are
|
|
not meant to be generic tools themselves but a mere API to actual
|
|
software.
|
|
|
|
---------------------------------------------------
|
|
+------+
|
|
+--> | tmux |
|
|
| +------+
|
|
|
|
|
+---------+ | +------+
|
|
| Kakoune | <-------> scripts +-+--> | X11 |
|
|
+---------+ | +------+
|
|
|
|
|
| +------+
|
|
+--> | ... |
|
|
+------+
|
|
---------------------------------------------------
|
|
|
|
Dependencies
|
|
------------
|
|
|
|
The amount of dependencies of a given script should be kept to a minimum
|
|
for practicality reasons, and have to be reasonable and expected
|
|
considering the purpose of the script itself.
|
|
|
|
Examples:
|
|
|
|
* the `clang.kak` script provides with code completion using the `clang`
|
|
compiler
|
|
|
|
* the `tmux.kak` script provides with terminal splitting using the
|
|
`tmux` multiplexer
|
|
|
|
* the `ctags.kak` script provides with symbol lookups using the
|
|
`readtags` utility provided by some `ctags` implementations
|
|
|
|
Naming convention
|
|
-----------------
|
|
|
|
All options and commands declared in a Kakoune script have to be
|
|
prefixed with the name of the script, or a one word description of the
|
|
purpose of the script.
|
|
|
|
Examples:
|
|
|
|
* in `tmux.kak`: command `tmux-new-window`
|
|
|
|
* in `comment.kak`: option `comment_line`
|
|
|
|
The following conventions apply as well:
|
|
|
|
* *options*: if a separator is needed to separate a multiple word option
|
|
name, an underscore should be used to allow shell scopes to use them
|
|
|
|
* *commands*: if a separator is needed, a hyphen is usually used to
|
|
differentiate a command name from an option's
|
|
|
|
Documentation
|
|
-------------
|
|
|
|
Non-hidden commands and options should always be declared with a documentation
|
|
string, so that their purpose is clearly described whenever completed upon
|
|
interactively from the prompt.
|
|
|
|
POSIX shell
|
|
-----------
|
|
|
|
Shell expansions are a useful tool to interact with an external utility,
|
|
and the shell code that they contain should be as portable as possible. As
|
|
such, scripts that rely on those expansions have to be implemented with
|
|
POSIX in mind, most shells follow this standard nowadays which somewhat
|
|
guarantees that the script will be portable across the most common systems.
|
|
|
|
Common shell patterns
|
|
---------------------
|
|
|
|
Printing variables
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
In order to print a string that contains a variable expansion, prefer
|
|
`printf` to `echo`, as the latter is implementation defined and may
|
|
interpret some characters differently depending on the shell (e.g.
|
|
flags, backslashes).
|
|
|
|
----------------------------------
|
|
printf %s\\n "${var}"
|
|
printf "value: %s\\n" "${var}"
|
|
----------------------------------
|
|
|
|
The following won't cause any issues, as the string to print doesn't
|
|
contain ambiguous characters:
|
|
|
|
-------------------------------------
|
|
echo "set global scrolloff 999,0"
|
|
-------------------------------------
|
|
|
|
Variable base name
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
Replace `$(basename "${var}")` with `"${var##*/}"`.
|
|
|
|
Testing
|
|
~~~~~~~
|
|
|
|
The `[[` keyword is provided by `bash`, and should be replaced with `[`.
|
|
|
|
Standard error redirection
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
Redirecting both standard and error streams is simplified in the `bash`
|
|
shell with the `&>` operator, however this syntax is not portable and
|
|
has to be replaced with the following: `>/dev/null 2>&1`.
|
|
|
|
Regular expression
|
|
~~~~~~~~~~~~~~~~~~
|
|
|
|
The `bash` shell provides with a `[[` keyword that supports the `=~`
|
|
operator to match a regular expression against a variable. This
|
|
functionality can be implemented with the `expr` utility:
|
|
|
|
* `expr "${var}" : '[a-z]*' >/dev/null` returns successfully when the
|
|
variable is empty or only contains lowercase characters, otherwise a
|
|
non-zero exit code is returned
|
|
|
|
* `expr "${var}" : '\([a-z]*\)'` prints the variable when empty or
|
|
only contains lowercase characters
|
|
|
|
Note that the regular expression matches the whole string, using the `^`
|
|
and `$` anchors is an undefined behavior.
|
|
|
|
Running a process in the background
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
In order to get a process running in the background without having it
|
|
quit when the shell scope that spawns it terminates, use the following
|
|
syntax:
|
|
|
|
--------------------------------
|
|
{
|
|
command
|
|
} </dev/null >/dev/null 2>&1 &
|
|
--------------------------------
|