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neovim/runtime/doc/lua.txt
Justin M. Keyes 9f3679cbfd docs: naming conventions
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*lua.txt* Nvim
NVIM REFERENCE MANUAL
Lua engine *lua* *Lua*
Type |gO| to see the table of contents.
==============================================================================
INTRODUCTION *lua-intro*
The Lua 5.1 language is builtin and always available. Try this command to get
an idea of what lurks beneath: >
:lua print(vim.inspect(package.loaded))
Nvim includes a "standard library" |lua-stdlib| for Lua. It complements the
"editor stdlib" (|functions| and Ex commands) and the |API|, all of which can
be used from Lua code. A good overview of using Lua in neovim is given by
https://github.com/nanotee/nvim-lua-guide.
Module conflicts are resolved by "last wins". For example if both of these
are on 'runtimepath':
runtime/lua/foo.lua
~/.config/nvim/lua/foo.lua
then `require('foo')` loads "~/.config/nvim/lua/foo.lua", and
"runtime/lua/foo.lua" is not used. See |lua-require| to understand how Nvim
finds and loads Lua modules. The conventions are similar to VimL plugins,
with some extra features. See |lua-require-example| for a walkthrough.
==============================================================================
IMPORTING LUA MODULES *lua-require*
*lua-package-path*
Nvim automatically adjusts `package.path` and `package.cpath` according to
effective 'runtimepath' value. Adjustment happens whenever 'runtimepath' is
changed. `package.path` is adjusted by simply appending `/lua/?.lua` and
`/lua/?/init.lua` to each directory from 'runtimepath' (`/` is actually the
first character of `package.config`).
Similarly to `package.path`, modified directories from 'runtimepath' are also
added to `package.cpath`. In this case, instead of appending `/lua/?.lua` and
`/lua/?/init.lua` to each runtimepath, all unique `?`-containing suffixes of
the existing `package.cpath` are used. Example:
1. Given that
- 'runtimepath' contains `/foo/bar,/xxx;yyy/baz,/abc`;
- initial (defined at compile-time or derived from
`$LUA_CPATH`/`$LUA_INIT`) `package.cpath` contains
`./?.so;/def/ghi/a?d/j/g.elf;/def/?.so`.
2. It finds `?`-containing suffixes `/?.so`, `/a?d/j/g.elf` and `/?.so`, in
order: parts of the path starting from the first path component containing
question mark and preceding path separator.
3. The suffix of `/def/?.so`, namely `/?.so` is not unique, as it’s the same
as the suffix of the first path from `package.path` (i.e. `./?.so`). Which
leaves `/?.so` and `/a?d/j/g.elf`, in this order.
4. 'runtimepath' has three paths: `/foo/bar`, `/xxx;yyy/baz` and `/abc`. The
second one contains semicolon which is a paths separator so it is out,
leaving only `/foo/bar` and `/abc`, in order.
5. The cartesian product of paths from 4. and suffixes from 3. is taken,
giving four variants. In each variant `/lua` path segment is inserted
between path and suffix, leaving
- `/foo/bar/lua/?.so`
- `/foo/bar/lua/a?d/j/g.elf`
- `/abc/lua/?.so`
- `/abc/lua/a?d/j/g.elf`
6. New paths are prepended to the original `package.cpath`.
The result will look like this:
`/foo/bar,/xxx;yyy/baz,/abc` ('runtimepath')
× `./?.so;/def/ghi/a?d/j/g.elf;/def/?.so` (`package.cpath`)
= `/foo/bar/lua/?.so;/foo/bar/lua/a?d/j/g.elf;/abc/lua/?.so;/abc/lua/a?d/j/g.elf;./?.so;/def/ghi/a?d/j/g.elf;/def/?.so`
Note:
- To track 'runtimepath' updates, paths added at previous update are
remembered and removed at the next update, while all paths derived from the
new 'runtimepath' are prepended as described above. This allows removing
paths when path is removed from 'runtimepath', adding paths when they are
added and reordering `package.path`/`package.cpath` content if 'runtimepath'
was reordered.
- Although adjustments happen automatically, Nvim does not track current
values of `package.path` or `package.cpath`. If you happen to delete some
paths from there you can set 'runtimepath' to trigger an update: >
let &runtimepath = &runtimepath
- Skipping paths from 'runtimepath' which contain semicolons applies both to
`package.path` and `package.cpath`. Given that there are some badly written
plugins using shell which will not work with paths containing semicolons it
is better to not have them in 'runtimepath' at all.
==============================================================================
Lua Syntax Information *lua-syntax-help*
While Lua has a simple syntax, there are a few things to understand,
particularly when looking at the documentation above.
*lua-syntax-call-function*
Lua functions can be called in multiple ways. Consider the function: >
local example_func = function(a, b)
print("A is: ", a)
print("B is: ", b)
end
The first way to call a function is: >
example_func(1, 2)
-- ==== Result ====
-- A is: 1
-- B is: 2
<
This way of calling a function is familiar to most scripting languages.
In Lua, it's important to understand that any function arguments that are
not supplied are automatically set to `nil`. For example: >
example_func(1)
-- ==== Result ====
-- A is: 1
-- B is: nil
<
Additionally, if any extra parameters are passed, they are discarded
completely.
In Lua, it is also possible (when only one argument is passed) to call the
function without any parentheses. This is most often used to approximate
"keyword"-style arguments with a single dictionary. For example: >
local func_with_opts = function(opts)
local will_do_foo = opts.foo
local filename = opts.filename
...
end
func_with_opts { foo = true, filename = "hello.world" }
<
In this style, each "parameter" is passed via keyword. It is still valid
to call the function in this style: >
func_with_opts({ foo = true, filename = "hello.world" })
<
But often in the documentation, you will see the former rather than the
latter style, due to its brevity (this is vim after all!).
------------------------------------------------------------------------------
LUA PLUGIN EXAMPLE *lua-require-example*
The following example plugin adds a command `:MakeCharBlob` which transforms
current buffer into a long `unsigned char` array. Lua contains transformation
function in a module `lua/charblob.lua` which is imported in
`autoload/charblob.vim` (`require("charblob")`). Example plugin is supposed
to be put into any directory from 'runtimepath', e.g. `~/.config/nvim` (in
this case `lua/charblob.lua` means `~/.config/nvim/lua/charblob.lua`).
autoload/charblob.vim: >
function charblob#encode_buffer()
call setline(1, luaeval(
\ 'require("charblob").encode(unpack(_A))',
\ [getline(1, '$'), &textwidth, ' ']))
endfunction
plugin/charblob.vim: >
if exists('g:charblob_loaded')
finish
endif
let g:charblob_loaded = 1
command MakeCharBlob :call charblob#encode_buffer()
lua/charblob.lua: >
local function charblob_bytes_iter(lines)
local init_s = {
next_line_idx = 1,
next_byte_idx = 1,
lines = lines,
}
local function next(s, _)
if lines[s.next_line_idx] == nil then
return nil
end
if s.next_byte_idx > #(lines[s.next_line_idx]) then
s.next_line_idx = s.next_line_idx + 1
s.next_byte_idx = 1
return ('\n'):byte()
end
local ret = lines[s.next_line_idx]:byte(s.next_byte_idx)
if ret == ('\n'):byte() then
ret = 0 -- See :h NL-used-for-NUL.
end
s.next_byte_idx = s.next_byte_idx + 1
return ret
end
return next, init_s, nil
end
local function charblob_encode(lines, textwidth, indent)
local ret = {
'const unsigned char blob[] = {',
indent,
}
for byte in charblob_bytes_iter(lines) do
-- .- space + number (width 3) + comma
if #(ret[#ret]) + 5 > textwidth then
ret[#ret + 1] = indent
else
ret[#ret] = ret[#ret] .. ' '
end
ret[#ret] = ret[#ret] .. (('%3u,'):format(byte))
end
ret[#ret + 1] = '};'
return ret
end
return {
bytes_iter = charblob_bytes_iter,
encode = charblob_encode,
}
==============================================================================
COMMANDS *lua-commands*
These commands execute a Lua chunk from either the command line (:lua, :luado)
or a file (:luafile) on the given line [range]. As always in Lua, each chunk
has its own scope (closure), so only global variables are shared between
command calls. The |lua-stdlib| modules, user modules, and anything else on
|lua-package-path| are available.
The Lua print() function redirects its output to the Nvim message area, with
arguments separated by " " (space) instead of "\t" (tab).
*:lua*
:[range]lua {chunk}
Executes Lua chunk {chunk}.
Examples: >
:lua vim.api.nvim_command('echo "Hello, Nvim!"')
< To see the Lua version: >
:lua print(_VERSION)
< To see the LuaJIT version: >
:lua print(jit.version)
<
*:lua-heredoc*
:[range]lua << [endmarker]
{script}
{endmarker}
Executes Lua script {script} from within Vimscript.
{endmarker} must NOT be preceded by whitespace. You
can omit [endmarker] after the "<<" and use a dot "."
after {script} (similar to |:append|, |:insert|).
Example:
>
function! CurrentLineInfo()
lua << EOF
local linenr = vim.api.nvim_win_get_cursor(0)[1]
local curline = vim.api.nvim_buf_get_lines(
0, linenr, linenr + 1, false)[1]
print(string.format("Current line [%d] has %d bytes",
linenr, #curline))
EOF
endfunction
< Note that the `local` variables will disappear when
the block finishes. But not globals.
*:luado*
:[range]luado {body} Executes Lua chunk "function(line, linenr) {body} end"
for each buffer line in [range], where `line` is the
current line text (without <EOL>), and `linenr` is the
current line number. If the function returns a string
that becomes the text of the corresponding buffer
line. Default [range] is the whole file: "1,$".
Examples:
>
:luado return string.format("%s\t%d", line:reverse(), #line)
:lua require"lpeg"
:lua -- balanced parenthesis grammar:
:lua bp = lpeg.P{ "(" * ((1 - lpeg.S"()") + lpeg.V(1))^0 * ")" }
:luado if bp:match(line) then return "-->\t" .. line end
<
*:luafile*
:[range]luafile {file}
Execute Lua script in {file}.
The whole argument is used as a single file name.
Examples:
>
:luafile script.lua
:luafile %
<
==============================================================================
luaeval() *lua-eval* *luaeval()*
The (dual) equivalent of "vim.eval" for passing Lua values to Nvim is
"luaeval". "luaeval" takes an expression string and an optional argument used
for _A inside expression and returns the result of the expression. It is
semantically equivalent in Lua to:
>
local chunkheader = "local _A = select(1, ...) return "
function luaeval (expstr, arg)
local chunk = assert(loadstring(chunkheader .. expstr, "luaeval"))
return chunk(arg) -- return typval
end
Lua nils, numbers, strings, tables and booleans are converted to their
respective VimL types. An error is thrown if conversion of any other Lua types
is attempted.
The magic global "_A" contains the second argument to luaeval().
Example: >
:echo luaeval('_A[1] + _A[2]', [40, 2])
42
:echo luaeval('string.match(_A, "[a-z]+")', 'XYXfoo123')
foo
Lua tables are used as both dictionaries and lists, so it is impossible to
determine whether empty table is meant to be empty list or empty dictionary.
Additionally Lua does not have integer numbers. To distinguish between these
cases there is the following agreement:
0. Empty table is empty list.
1. Table with N incrementally growing integral numbers, starting from 1 and
ending with N is considered to be a list.
2. Table with string keys, none of which contains NUL byte, is considered to
be a dictionary.
3. Table with string keys, at least one of which contains NUL byte, is also
considered to be a dictionary, but this time it is converted to
a |msgpack-special-map|.
*lua-special-tbl*
4. Table with `vim.type_idx` key may be a dictionary, a list or floating-point
value:
- `{[vim.type_idx]=vim.types.float, [vim.val_idx]=1}` is converted to
a floating-point 1.0. Note that by default integral Lua numbers are
converted to |Number|s, non-integral are converted to |Float|s. This
variant allows integral |Float|s.
- `{[vim.type_idx]=vim.types.dictionary}` is converted to an empty
dictionary, `{[vim.type_idx]=vim.types.dictionary, [42]=1, a=2}` is
converted to a dictionary `{'a': 42}`: non-string keys are ignored.
Without `vim.type_idx` key tables with keys not fitting in 1., 2. or 3.
are errors.
- `{[vim.type_idx]=vim.types.list}` is converted to an empty list. As well
as `{[vim.type_idx]=vim.types.list, [42]=1}`: integral keys that do not
form a 1-step sequence from 1 to N are ignored, as well as all
non-integral keys.
Examples: >
:echo luaeval('math.pi')
:function Rand(x,y) " random uniform between x and y
: return luaeval('(_A.y-_A.x)*math.random()+_A.x', {'x':a:x,'y':a:y})
: endfunction
:echo Rand(1,10)
Note: second argument to `luaeval` undergoes VimL to Lua conversion
("marshalled"), so changes to Lua containers do not affect values in VimL.
Return value is also always converted. When converting,
|msgpack-special-dict|s are treated specially.
==============================================================================
Vimscript v:lua interface *v:lua-call*
From Vimscript the special `v:lua` prefix can be used to call Lua functions
which are global or accessible from global tables. The expression >
v:lua.func(arg1, arg2)
is equivalent to the Lua chunk >
return func(...)
where the args are converted to Lua values. The expression >
v:lua.somemod.func(args)
is equivalent to the Lua chunk >
return somemod.func(...)
The `v:lua` prefix may be used to call Lua functions as |method|s. For
example: >
arg1->v:lua.somemod.func(arg2)
You can use `v:lua` in "func" options like 'tagfunc', 'omnifunc', etc.
For example consider the following Lua omnifunc handler: >
function mymod.omnifunc(findstart, base)
if findstart == 1 then
return 0
else
return {'stuff', 'steam', 'strange things'}
end
end
vim.api.nvim_buf_set_option(0, 'omnifunc', 'v:lua.mymod.omnifunc')
Note: the module ("mymod" in the above example) must be a Lua global.
Note: `v:lua` without a call is not allowed in a Vimscript expression:
|Funcref|s cannot represent Lua functions. The following are errors: >
let g:Myvar = v:lua.myfunc " Error
call SomeFunc(v:lua.mycallback) " Error
let g:foo = v:lua " Error
let g:foo = v:['lua'] " Error
==============================================================================
Lua standard modules *lua-stdlib*
The Nvim Lua "standard library" (stdlib) is the `vim` module, which exposes
various functions and sub-modules. It is always loaded, thus require("vim")
is unnecessary.
You can peek at the module properties: >
:lua print(vim.inspect(vim))
Result is something like this: >
{
_os_proc_children = <function 1>,
_os_proc_info = <function 2>,
...
api = {
nvim__id = <function 5>,
nvim__id_array = <function 6>,
...
},
deepcopy = <function 106>,
gsplit = <function 107>,
...
}
To find documentation on e.g. the "deepcopy" function: >
:help vim.deepcopy()
Note that underscore-prefixed functions (e.g. "_os_proc_children") are
internal/private and must not be used by plugins.
------------------------------------------------------------------------------
VIM.LOOP *lua-loop* *vim.loop*
`vim.loop` exposes all features of the Nvim event-loop. This is a low-level
API that provides functionality for networking, filesystem, and process
management. Try this command to see available functions: >
:lua print(vim.inspect(vim.loop))
Reference: https://github.com/luvit/luv/blob/master/docs.md
Examples: https://github.com/luvit/luv/tree/master/examples
*E5560* *lua-loop-callbacks*
It is an error to directly invoke `vim.api` functions (except |api-fast|) in
`vim.loop` callbacks. For example, this is an error: >
local timer = vim.loop.new_timer()
timer:start(1000, 0, function()
vim.api.nvim_command('echomsg "test"')
end)
To avoid the error use |vim.schedule_wrap()| to defer the callback: >
local timer = vim.loop.new_timer()
timer:start(1000, 0, vim.schedule_wrap(function()
vim.api.nvim_command('echomsg "test"')
end))
(For one-shot timers, see |vim.defer_fn()|, which automatically adds the wrapping.)
Example: repeating timer
1. Save this code to a file.
2. Execute it with ":luafile %". >
-- Create a timer handle (implementation detail: uv_timer_t).
local timer = vim.loop.new_timer()
local i = 0
-- Waits 1000ms, then repeats every 750ms until timer:close().
timer:start(1000, 750, function()
print('timer invoked! i='..tostring(i))
if i > 4 then
timer:close() -- Always close handles to avoid leaks.
end
i = i + 1
end)
print('sleeping');
Example: File-change detection *watch-file*
1. Save this code to a file.
2. Execute it with ":luafile %".
3. Use ":Watch %" to watch any file.
4. Try editing the file from another text editor.
5. Observe that the file reloads in Nvim (because on_change() calls
|:checktime|). >
local w = vim.loop.new_fs_event()
local function on_change(err, fname, status)
-- Do work...
vim.api.nvim_command('checktime')
-- Debounce: stop/start.
w:stop()
watch_file(fname)
end
function watch_file(fname)
local fullpath = vim.api.nvim_call_function(
'fnamemodify', {fname, ':p'})
w:start(fullpath, {}, vim.schedule_wrap(function(...)
on_change(...) end))
end
vim.api.nvim_command(
"command! -nargs=1 Watch call luaeval('watch_file(_A)', expand('<args>'))")
Example: TCP echo-server *tcp-server*
1. Save this code to a file.
2. Execute it with ":luafile %".
3. Note the port number.
4. Connect from any TCP client (e.g. "nc 0.0.0.0 36795"): >
local function create_server(host, port, on_connect)
local server = vim.loop.new_tcp()
server:bind(host, port)
server:listen(128, function(err)
assert(not err, err) -- Check for errors.
local sock = vim.loop.new_tcp()
server:accept(sock) -- Accept client connection.
on_connect(sock) -- Start reading messages.
end)
return server
end
local server = create_server('0.0.0.0', 0, function(sock)
sock:read_start(function(err, chunk)
assert(not err, err) -- Check for errors.
if chunk then
sock:write(chunk) -- Echo received messages to the channel.
else -- EOF (stream closed).
sock:close() -- Always close handles to avoid leaks.
end
end)
end)
print('TCP echo-server listening on port: '..server:getsockname().port)
------------------------------------------------------------------------------
VIM.HIGHLIGHT *lua-highlight*
Nvim includes a function for highlighting a selection on yank (see for example
https://github.com/machakann/vim-highlightedyank). To enable it, add
>
au TextYankPost * silent! lua vim.highlight.on_yank()
<
to your `init.vim`. You can customize the highlight group and the duration of
the highlight via
>
au TextYankPost * silent! lua vim.highlight.on_yank {higroup="IncSearch", timeout=150}
<
If you want to exclude visual selections from highlighting on yank, use
>
au TextYankPost * silent! lua vim.highlight.on_yank {on_visual=false}
<
vim.highlight.on_yank({opts}) *vim.highlight.on_yank()*
Highlights the yanked text. The fields of the optional dict {opts}
control the highlight:
- {higroup} highlight group for yanked region (default |hl-IncSearch|)
- {timeout} time in ms before highlight is cleared (default `150`)
- {on_macro} highlight when executing macro (default `false`)
- {on_visual} highlight when yanking visual selection (default `true`)
- {event} event structure (default |v:event|)
vim.highlight.range({bufnr}, {ns}, {higroup}, {start}, {finish}, {rtype}, {inclusive})
*vim.highlight.range()*
Highlights the range between {start} and {finish} (tuples of {line,col})
in buffer {bufnr} with the highlight group {higroup} using the namespace
{ns}. Optional arguments are the type of range (characterwise, linewise,
or blockwise, see |setreg|; default to characterwise) and whether the
range is inclusive (default false).
------------------------------------------------------------------------------
VIM.REGEX *lua-regex*
Vim regexes can be used directly from lua. Currently they only allow
matching within a single line.
vim.regex({re}) *vim.regex()*
Parse the regex {re} and return a regex object. 'magic' and
'ignorecase' options are ignored, lua regexes always defaults to magic
and ignoring case. The behavior can be changed with flags in
the beginning of the string |/magic|.
Regex objects support the following methods:
regex:match_str({str}) *regex:match_str()*
Match the string against the regex. If the string should match the
regex precisely, surround the regex with `^` and `$`.
If the was a match, the byte indices for the beginning and end of
the match is returned. When there is no match, `nil` is returned.
As any integer is truth-y, `regex:match()` can be directly used
as a condition in an if-statement.
regex:match_line({bufnr}, {line_idx}[, {start}, {end}]) *regex:match_line()*
Match line {line_idx} (zero-based) in buffer {bufnr}. If {start} and
{end} are supplied, match only this byte index range. Otherwise see
|regex:match_str()|. If {start} is used, then the returned byte
indices will be relative {start}.
------------------------------------------------------------------------------
VIM.DIFF *lua-diff*
vim.diff({a}, {b}, {opts}) *vim.diff()*
Run diff on strings {a} and {b}. Any indices returned by this
function, either directly or via callback arguments, are
1-based.
Examples: >
vim.diff('a\n', 'b\nc\n')
-->
@@ -1 +1,2 @@
-a
+b
+c
vim.diff('a\n', 'b\nc\n', {result_type = 'indices'})
-->
{
{1, 1, 1, 2}
}
<
Parameters: ~
{a} First string to compare
{b} Second string to compare
{opts} Optional parameters:
• `on_hunk` (callback):
Invoked for each hunk in the diff. Return a
negative number to cancel the callback for any
remaining hunks.
Args:
• `start_a` (integer): Start line of hunk in {a}.
• `count_a` (integer): Hunk size in {a}.
• `start_b` (integer): Start line of hunk in {b}.
• `count_b` (integer): Hunk size in {b}.
• `result_type` (string): Form of the returned diff:
• "unified": (default) String in unified format.
• "indices": Array of hunk locations.
Note this option is ignored if `on_hunk` is
used.
• `algorithm` (string):
Diff algorithm to use. Values:
• "myers" the default algorithm
• "minimal" spend extra time to generate the
smallest possible diff
• "patience" patience diff algorithm
• "histogram" histogram diff algorithm
• `ctxlen` (integer): Context length
• `interhunkctxlen` (integer):
Inter hunk context length
• `ignore_whitespace` (boolean):
Ignore whitespace
• `ignore_whitespace_change` (boolean):
Ignore whitespace change
• `ignore_whitespace_change_at_eol` (boolean)
Ignore whitespace change at end-of-line.
• `ignore_cr_at_eol` (boolean)
Ignore carriage return at end-of-line
• `ignore_blank_lines` (boolean)
Ignore blank lines
• `indent_heuristic` (boolean):
Use the indent heuristic for the internal
diff library.
Return: ~
See {opts.result_type}. nil if {opts.on_hunk} is given.
------------------------------------------------------------------------------
VIM *lua-builtin*
vim.api.{func}({...}) *vim.api*
Invokes Nvim |API| function {func} with arguments {...}.
Example: call the "nvim_get_current_line()" API function: >
print(tostring(vim.api.nvim_get_current_line()))
vim.version() *vim.version*
Returns the version of the current neovim build.
vim.in_fast_event() *vim.in_fast_event()*
Returns true if the code is executing as part of a "fast" event
handler, where most of the API is disabled. These are low-level events
(e.g. |lua-loop-callbacks|) which can be invoked whenever Nvim polls
for input. When this is `false` most API functions are callable (but
may be subject to other restrictions such as |textlock|).
vim.NIL *vim.NIL*
Special value used to represent NIL in msgpack-rpc and |v:null| in
vimL interaction, and similar cases. Lua `nil` cannot be used as
part of a lua table representing a Dictionary or Array, as it
is equivalent to a missing value: `{"foo", nil}` is the same as
`{"foo"}`
vim.empty_dict() *vim.empty_dict()*
Creates a special table which will be converted to an empty
dictionary when converting lua values to vimL or API types. The
table is empty, and this property is marked using a metatable. An
empty table `{}` without this metatable will default to convert to
an array/list.
Note: if numeric keys are added to the table, the metatable will be
ignored and the dict converted to a list/array anyway.
vim.rpcnotify({channel}, {method}[, {args}...]) *vim.rpcnotify()*
Sends {event} to {channel} via |RPC| and returns immediately.
If {channel} is 0, the event is broadcast to all channels.
This function also works in a fast callback |lua-loop-callbacks|.
vim.rpcrequest({channel}, {method}[, {args}...]) *vim.rpcrequest()*
Sends a request to {channel} to invoke {method} via
|RPC| and blocks until a response is received.
Note: NIL values as part of the return value is represented as
|vim.NIL| special value
vim.stricmp({a}, {b}) *vim.stricmp()*
Compares strings case-insensitively. Returns 0, 1 or -1 if strings
are equal, {a} is greater than {b} or {a} is lesser than {b},
respectively.
vim.str_utfindex({str}[, {index}]) *vim.str_utfindex()*
Convert byte index to UTF-32 and UTF-16 indicies. If {index} is not
supplied, the length of the string is used. All indicies are zero-based.
Returns two values: the UTF-32 and UTF-16 indicies respectively.
Embedded NUL bytes are treated as terminating the string. Invalid
UTF-8 bytes, and embedded surrogates are counted as one code
point each. An {index} in the middle of a UTF-8 sequence is rounded
upwards to the end of that sequence.
vim.str_byteindex({str}, {index}[, {use_utf16}]) *vim.str_byteindex()*
Convert UTF-32 or UTF-16 {index} to byte index. If {use_utf16} is not
supplied, it defaults to false (use UTF-32). Returns the byte index.
Invalid UTF-8 and NUL is treated like by |vim.str_byteindex()|. An {index}
in the middle of a UTF-16 sequence is rounded upwards to the end of that
sequence.
vim.schedule({callback}) *vim.schedule()*
Schedules {callback} to be invoked soon by the main event-loop. Useful
to avoid |textlock| or other temporary restrictions.
vim.defer_fn({fn}, {timeout}) *vim.defer_fn*
Defers calling {fn} until {timeout} ms passes. Use to do a one-shot timer
that calls {fn}.
Note: The {fn} is |schedule_wrap|ped automatically, so API functions are
safe to call.
Parameters: ~
{fn} Callback to call once {timeout} expires
{timeout} Time in ms to wait before calling {fn}
Returns: ~
|vim.loop|.new_timer() object
vim.wait({time} [, {callback}, {interval}, {fast_only}]) *vim.wait()*
Wait for {time} in milliseconds until {callback} returns `true`.
Executes {callback} immediately and at approximately {interval}
milliseconds (default 200). Nvim still processes other events during
this time.
Parameters: ~
{time} Number of milliseconds to wait
{callback} Optional callback. Waits until {callback} returns true
{interval} (Approximate) number of milliseconds to wait between polls
{fast_only} If true, only |api-fast| events will be processed.
If called from while in an |api-fast| event, will
automatically be set to `true`.
Returns: ~
If {callback} returns `true` during the {time}:
`true, nil`
If {callback} never returns `true` during the {time}:
`false, -1`
If {callback} is interrupted during the {time}:
`false, -2`
If {callback} errors, the error is raised.
Examples: >
---
-- Wait for 100 ms, allowing other events to process
vim.wait(100, function() end)
---
-- Wait for 100 ms or until global variable set.
vim.wait(100, function() return vim.g.waiting_for_var end)
---
-- Wait for 1 second or until global variable set, checking every ~500 ms
vim.wait(1000, function() return vim.g.waiting_for_var end, 500)
---
-- Schedule a function to set a value in 100ms
vim.defer_fn(function() vim.g.timer_result = true end, 100)
-- Would wait ten seconds if results blocked. Actually only waits 100 ms
if vim.wait(10000, function() return vim.g.timer_result end) then
print('Only waiting a little bit of time!')
end
<
vim.type_idx *vim.type_idx*
Type index for use in |lua-special-tbl|. Specifying one of the
values from |vim.types| allows typing the empty table (it is
unclear whether empty Lua table represents empty list or empty array)
and forcing integral numbers to be |Float|. See |lua-special-tbl| for
more details.
vim.val_idx *vim.val_idx*
Value index for tables representing |Float|s. A table representing
floating-point value 1.0 looks like this: >
{
[vim.type_idx] = vim.types.float,
[vim.val_idx] = 1.0,
}
< See also |vim.type_idx| and |lua-special-tbl|.
vim.types *vim.types*
Table with possible values for |vim.type_idx|. Contains two sets
of key-value pairs: first maps possible values for |vim.type_idx|
to human-readable strings, second maps human-readable type names to
values for |vim.type_idx|. Currently contains pairs for `float`,
`array` and `dictionary` types.
Note: one must expect that values corresponding to `vim.types.float`,
`vim.types.array` and `vim.types.dictionary` fall under only two
following assumptions:
1. Value may serve both as a key and as a value in a table. Given the
properties of Lua tables this basically means “value is not `nil`”.
2. For each value in `vim.types` table `vim.types[vim.types[value]]`
is the same as `value`.
No other restrictions are put on types, and it is not guaranteed that
values corresponding to `vim.types.float`, `vim.types.array` and
`vim.types.dictionary` will not change or that `vim.types` table will
only contain values for these three types.
------------------------------------------------------------------------------
LUA-VIMSCRIPT BRIDGE *lua-vimscript*
Nvim Lua provides an interface to Vimscript variables and functions, and
editor commands and options.
See also https://github.com/nanotee/nvim-lua-guide.
vim.call({func}, {...}) *vim.call()*
Invokes |vim-function| or |user-function| {func} with arguments {...}.
See also |vim.fn|.
Equivalent to: >
vim.fn[func]({...})
vim.cmd({cmd}) *vim.cmd()*
Executes multiple lines of Vimscript at once. It is an alias to
|nvim_exec()|, where `output` is set to false. Thus it works identical
to |:source|.
See also |ex-cmd-index|.
Example: >
vim.cmd('echo 42')
vim.cmd([[
augroup My_group
autocmd!
autocmd FileType c setlocal cindent
augroup END
]])
vim.fn.{func}({...}) *vim.fn*
Invokes |vim-function| or |user-function| {func} with arguments {...}.
To call autoload functions, use the syntax: >
vim.fn['some#function']({...})
<
Unlike vim.api.|nvim_call_function| this converts directly between Vim
objects and Lua objects. If the Vim function returns a float, it will
be represented directly as a Lua number. Empty lists and dictionaries
both are represented by an empty table.
Note: |v:null| values as part of the return value is represented as
|vim.NIL| special value
Note: vim.fn keys are generated lazily, thus `pairs(vim.fn)` only
enumerates functions that were called at least once.
*lua-vim-variables*
The Vim editor global dictionaries |g:| |w:| |b:| |t:| |v:| can be accessed
from Lua conveniently and idiomatically by referencing the `vim.*` Lua tables
described below. In this way you can easily read and modify global Vimscript
variables from Lua.
Example: >
vim.g.foo = 5 -- Set the g:foo Vimscript variable.
print(vim.g.foo) -- Get and print the g:foo Vimscript variable.
vim.g.foo = nil -- Delete (:unlet) the Vimscript variable.
vim.g *vim.g*
Global (|g:|) editor variables.
Key with no value returns `nil`.
vim.b *vim.b*
Buffer-scoped (|b:|) variables for the current buffer.
Invalid or unset key returns `nil`.
vim.w *vim.w*
Window-scoped (|w:|) variables for the current window.
Invalid or unset key returns `nil`.
vim.t *vim.t*
Tabpage-scoped (|t:|) variables for the current tabpage.
Invalid or unset key returns `nil`.
vim.v *vim.v*
|v:| variables.
Invalid or unset key returns `nil`.
vim.env *vim.env*
Environment variables defined in the editor session.
See |expand-env| and |:let-environment| for the Vimscript behavior.
Invalid or unset key returns `nil`.
Example: >
vim.env.FOO = 'bar'
print(vim.env.TERM)
<
*lua-vim-options*
*lua-vim-opt*
*lua-vim-set*
*lua-vim-optlocal*
*lua-vim-setlocal*
In vimL, there is a succint and simple way to set options. For more
information, see |set-option|. In Lua, the corresponding method is `vim.opt`.
`vim.opt` provides several conveniences for setting and controlling options
from within Lua.
Examples: ~
To set a boolean toggle:
In vimL:
`set number`
In Lua:
`vim.opt.number = true`
To set an array of values:
In vimL:
`set wildignore=*.o,*.a,__pycache__`
In Lua, there are two ways you can do this now. One is very similar to
the vimL way:
`vim.opt.wildignore = '*.o,*.a,__pycache__'`
However, vim.opt also supports a more elegent way of setting
list-style options, but using lua tables:
`vim.opt.wildignore = { '*.o', '*.a', '__pycache__' }`
To replicate the behavior of |:set+=|, use: >
-- vim.opt supports appending options via the "+" operator
vim.opt.wildignore = vim.opt.wildignore + { "*.pyc", "node_modules" }
-- or using the `:append(...)` method
vim.opt.wildignore:append { "*.pyc", "node_modules" }
<
To replicate the behavior of |:set^=|, use: >
-- vim.opt supports prepending options via the "^" operator
vim.opt.wildignore = vim.opt.wildignore ^ { "new_first_value" }
-- or using the `:prepend(...)` method
vim.opt.wildignore:prepend { "new_first_value" }
<
To replicate the behavior of |:set-=|, use: >
-- vim.opt supports removing options via the "-" operator
vim.opt.wildignore = vim.opt.wildignore - { "node_modules" }
-- or using the `:remove(...)` method
vim.opt.wildignore:remove { "node_modules" }
<
To set a map of values:
In vimL:
`set listchars=space:_,tab:>~`
In Lua:
`vim.opt.listchars = { space = '_', tab = '>~' }`
In any of the above examples, to replicate the behavior |setlocal|, use
`vim.opt_local`. Additionally, to replicate the behavior of |setglobal|, use
`vim.opt_global`.
*vim.opt*
|vim.opt| returns an Option object.
For example: `local listchar_object = vim.opt.listchar`
An `Option` has the following methods:
*vim.opt:get()*
Option:get()
Returns a lua-representation of the option. Boolean, number and string
values will be returned in exactly the same fashion.
For values that are comma-separated lists, an array will be returned with
the values as entries in the array: >
vim.cmd [[set wildignore=*.pyc,*.o]]
print(vim.inspect(vim.opt.wildignore:get()))
-- { "*.pyc", "*.o", }
for _, ignore_pattern in ipairs(vim.opt.wildignore:get()) do
print("Will ignore:", ignore_pattern)
end
-- Will ignore: *.pyc
-- Will ignore: *.o
<
For values that are comma-separated maps, a table will be returned with
the names as keys and the values as entries: >
vim.cmd [[set listchars=space:_,tab:>~]]
print(vim.inspect(vim.opt.listchars:get()))
-- { space = "_", tab = ">~", }
for char, representation in pairs(vim.opt.listchars:get()) do
print(char, "->", representation)
end
<
For values that are lists of flags, a set will be returned with the flags
as keys and `true` as entries. >
vim.cmd [[set formatoptions=njtcroql]]
print(vim.inspect(vim.opt.formatoptions:get()))
-- { n = true, j = true, c = true, ... }
local format_opts = vim.opt.formatoptions:get()
if format_opts.j then
print("J is enabled!")
end
<
*vim.opt:append()*
Option:append(value)
Append a value to string-style options. See |:set+=|
These are equivalent:
`vim.opt.formatoptions:append('j')`
`vim.opt.formatoptions = vim.opt.formatoptions + 'j'`
*vim.opt:prepend()*
Option:prepend(value)
Prepend a value to string-style options. See |:set^=|
These are equivalent:
`vim.opt.wildignore:prepend('*.o')`
`vim.opt.wildignore = vim.opt.wildignore ^ '*.o'`
*vim.opt:remove()*
Option:remove(value)
Remove a value from string-style options. See |:set-=|
These are equivalent:
`vim.opt.wildignore:remove('*.pyc')`
`vim.opt.wildignore = vim.opt.wildignore - '*.pyc'`
In general, using `vim.opt` will provide the expected result when the user is
used to interacting with editor |options| via `set`. There are still times
where the user may want to set particular options via a shorthand in Lua,
which is where |vim.o|, |vim.bo|, |vim.wo|, and |vim.go| come into play.
The behavior of |vim.o|, |vim.bo|, |vim.wo|, and |vim.go| is designed to
follow that of |:set|, |:setlocal|, and |:setglobal| which can be seen in the
table below:
lua command global_value local_value ~
vim.o :set set set
vim.bo/vim.wo :setlocal - set
vim.go :setglobal set -
vim.o *vim.o*
Get or set editor options, like |:set|. Invalid key is an error.
Example: >
vim.o.cmdheight = 4
print(vim.o.columns)
vim.go *vim.go*
Get or set an |option|. Invalid key is an error.
This is a wrapper around |nvim_set_option()| and |nvim_get_option()|.
NOTE: This is different than |vim.o| because this ONLY sets the global
option, which generally produces confusing behavior for options with
|global-local| values.
Example: >
vim.go.cmdheight = 4
<
vim.bo *vim.bo*
Get or set buffer-scoped |local-options|. Invalid key is an error.
This is a wrapper around |nvim_buf_set_option()| and
|nvim_buf_get_option()|.
Example: >
vim.bo.buflisted = true
print(vim.bo.comments)
vim.wo *vim.wo*
Get or set window-scoped |local-options|. Invalid key is an error.
This is a wrapper around |nvim_win_set_option()| and
|nvim_win_get_option()|.
Example: >
vim.wo.cursorcolumn = true
print(vim.wo.foldmarker)
==============================================================================
Lua module: vim *lua-vim*
defer_fn({fn}, {timeout}) *vim.defer_fn()*
Defers calling `fn` until `timeout` ms passes.
Use to do a one-shot timer that calls `fn` Note: The {fn} is |schedule_wrap|ped automatically, so API
functions are safe to call.
Parameters: ~
{fn} Callback to call once `timeout` expires
{timeout} Number of milliseconds to wait before calling
`fn`
Return: ~
timer luv timer object
insert_keys({obj}) *vim.insert_keys()*
TODO: Documentation
inspect({object}, {options}) *vim.inspect()*
Return a human-readable representation of the given object.
See also: ~
https://github.com/kikito/inspect.lua
https://github.com/mpeterv/vinspect
make_dict_accessor({scope}) *vim.make_dict_accessor()*
TODO: Documentation
notify({msg}, {log_level}, {_opts}) *vim.notify()*
Notification provider
Without a runtime, writes to :Messages
Parameters: ~
{msg} Content of the notification to show to the
user
{log_level} Optional log level
{opts} Dictionary with optional options (timeout,
etc)
See also: ~
:help nvim_notify
paste({lines}, {phase}) *vim.paste()*
Paste handler, invoked by |nvim_paste()| when a conforming UI
(such as the |TUI|) pastes text into the editor.
Example: To remove ANSI color codes when pasting: >
vim.paste = (function(overridden)
return function(lines, phase)
for i,line in ipairs(lines) do
-- Scrub ANSI color codes from paste input.
lines[i] = line:gsub('\27%[[0-9;mK]+', '')
end
overridden(lines, phase)
end
end)(vim.paste)
<
Parameters: ~
{lines} |readfile()|-style list of lines to paste.
|channel-lines|
{phase} -1: "non-streaming" paste: the call contains all
lines. If paste is "streamed", `phase` indicates the stream state:
• 1: starts the paste (exactly once)
• 2: continues the paste (zero or more times)
• 3: ends the paste (exactly once)
Return: ~
false if client should cancel the paste.
See also: ~
|paste|
region({bufnr}, {pos1}, {pos2}, {regtype}, {inclusive}) *vim.region()*
Get a table of lines with start, end columns for a region
marked by two points
Parameters: ~
{bufnr} number of buffer
{pos1} (line, column) tuple marking beginning of
region
{pos2} (line, column) tuple marking end of region
{regtype} type of selection (:help setreg)
{inclusive} boolean indicating whether the selection is
end-inclusive
Return: ~
region lua table of the form {linenr = {startcol,endcol}}
schedule_wrap({cb}) *vim.schedule_wrap()*
Defers callback `cb` until the Nvim API is safe to call.
See also: ~
|lua-loop-callbacks|
|vim.schedule()|
|vim.in_fast_event()|
deep_equal({a}, {b}) *vim.deep_equal()*
TODO: Documentation
deepcopy({orig}) *vim.deepcopy()*
Returns a deep copy of the given object. Non-table objects are
copied as in a typical Lua assignment, whereas table objects
are copied recursively. Functions are naively copied, so
functions in the copied table point to the same functions as
those in the input table. Userdata and threads are not copied
and will throw an error.
Parameters: ~
{orig} Table to copy
Return: ~
New table of copied keys and (nested) values.
endswith({s}, {suffix}) *vim.endswith()*
Tests if `s` ends with `suffix` .
Parameters: ~
{s} (string) a string
{suffix} (string) a suffix
Return: ~
(boolean) true if `suffix` is a suffix of s
gsplit({s}, {sep}, {plain}) *vim.gsplit()*
Splits a string at each instance of a separator.
Parameters: ~
{s} String to split
{sep} Separator string or pattern
{plain} If `true` use `sep` literally (passed to
String.find)
Return: ~
Iterator over the split components
See also: ~
|vim.split()|
https://www.lua.org/pil/20.2.html
http://lua-users.org/wiki/StringLibraryTutorial
is_callable({f}) *vim.is_callable()*
Returns true if object `f` can be called as a function.
Parameters: ~
{f} Any object
Return: ~
true if `f` is callable, else false
is_valid({opt}) *vim.is_valid()*
TODO: Documentation
list_extend({dst}, {src}, {start}, {finish}) *vim.list_extend()*
Extends a list-like table with the values of another list-like
table.
NOTE: This mutates dst!
Parameters: ~
{dst} list which will be modified and appended to.
{src} list from which values will be inserted.
{start} Start index on src. defaults to 1
{finish} Final index on src. defaults to #src
Return: ~
dst
See also: ~
|vim.tbl_extend()|
list_slice({list}, {start}, {finish}) *vim.list_slice()*
Creates a copy of a table containing only elements from start
to end (inclusive)
Parameters: ~
{list} table table
{start} integer Start range of slice
{finish} integer End range of slice
Return: ~
Copy of table sliced from start to finish (inclusive)
pesc({s}) *vim.pesc()*
Escapes magic chars in a Lua pattern.
Parameters: ~
{s} String to escape
Return: ~
%-escaped pattern string
See also: ~
https://github.com/rxi/lume
split({s}, {sep}, {plain}) *vim.split()*
Splits a string at each instance of a separator.
Examples: >
split(":aa::b:", ":") --> {'','aa','','b',''}
split("axaby", "ab?") --> {'','x','y'}
split(x*yz*o, "*", true) --> {'x','yz','o'}
<
Parameters: ~
{s} String to split
{sep} Separator string or pattern
{plain} If `true` use `sep` literally (passed to
String.find)
Return: ~
List-like table of the split components.
See also: ~
|vim.gsplit()|
startswith({s}, {prefix}) *vim.startswith()*
Tests if `s` starts with `prefix` .
Parameters: ~
{s} (string) a string
{prefix} (string) a prefix
Return: ~
(boolean) true if `prefix` is a prefix of s
tbl_add_reverse_lookup({o}) *vim.tbl_add_reverse_lookup()*
Add the reverse lookup values to an existing table. For
example: tbl_add_reverse_lookup { A = 1 } == { [1] = 'A , A = 1 }`
Parameters: ~
{o} table The table to add the reverse to.
tbl_contains({t}, {value}) *vim.tbl_contains()*
Checks if a list-like (vector) table contains `value` .
Parameters: ~
{t} Table to check
{value} Value to compare
Return: ~
true if `t` contains `value`
tbl_count({t}) *vim.tbl_count()*
Counts the number of non-nil values in table `t` .
>
vim.tbl_count({ a=1, b=2 }) => 2
vim.tbl_count({ 1, 2 }) => 2
<
Parameters: ~
{t} Table
Return: ~
Number that is the number of the value in table
See also: ~
https://github.com/Tieske/Penlight/blob/master/lua/pl/tablex.lua
tbl_deep_extend({behavior}, {...}) *vim.tbl_deep_extend()*
Merges recursively two or more map-like tables.
Parameters: ~
{behavior} Decides what to do if a key is found in more
than one map:
• "error": raise an error
• "keep": use value from the leftmost map
• "force": use value from the rightmost map
{...} Two or more map-like tables.
See also: ~
|tbl_extend()|
tbl_extend({behavior}, {...}) *vim.tbl_extend()*
Merges two or more map-like tables.
Parameters: ~
{behavior} Decides what to do if a key is found in more
than one map:
• "error": raise an error
• "keep": use value from the leftmost map
• "force": use value from the rightmost map
{...} Two or more map-like tables.
See also: ~
|extend()|
tbl_filter({func}, {t}) *vim.tbl_filter()*
Filter a table using a predicate function
Parameters: ~
{func} function or callable table
{t} table
tbl_flatten({t}) *vim.tbl_flatten()*
Creates a copy of a list-like table such that any nested
tables are "unrolled" and appended to the result.
Parameters: ~
{t} List-like table
Return: ~
Flattened copy of the given list-like table.
See also: ~
Fromhttps://github.com/premake/premake-core/blob/master/src/base/table.lua
tbl_isempty({t}) *vim.tbl_isempty()*
Checks if a table is empty.
Parameters: ~
{t} Table to check
See also: ~
https://github.com/premake/premake-core/blob/master/src/base/table.lua
tbl_islist({t}) *vim.tbl_islist()*
Tests if a Lua table can be treated as an array.
Empty table `{}` is assumed to be an array, unless it was
created by |vim.empty_dict()| or returned as a dict-like |API|
or Vimscript result, for example from |rpcrequest()| or
|vim.fn|.
Parameters: ~
{t} Table
Return: ~
`true` if array-like table, else `false` .
tbl_keys({t}) *vim.tbl_keys()*
Return a list of all keys used in a table. However, the order
of the return table of keys is not guaranteed.
Parameters: ~
{t} Table
Return: ~
list of keys
See also: ~
Fromhttps://github.com/premake/premake-core/blob/master/src/base/table.lua
tbl_map({func}, {t}) *vim.tbl_map()*
Apply a function to all values of a table.
Parameters: ~
{func} function or callable table
{t} table
tbl_values({t}) *vim.tbl_values()*
Return a list of all values used in a table. However, the
order of the return table of values is not guaranteed.
Parameters: ~
{t} Table
Return: ~
list of values
trim({s}) *vim.trim()*
Trim whitespace (Lua pattern "%s") from both sides of a
string.
Parameters: ~
{s} String to trim
Return: ~
String with whitespace removed from its beginning and end
See also: ~
https://www.lua.org/pil/20.2.html
validate({opt}) *vim.validate()*
Validates a parameter specification (types and values).
Usage example: >
function user.new(name, age, hobbies)
vim.validate{
name={name, 'string'},
age={age, 'number'},
hobbies={hobbies, 'table'},
}
...
end
<
Examples with explicit argument values (can be run directly): >
vim.validate{arg1={{'foo'}, 'table'}, arg2={'foo', 'string'}}
=> NOP (success)
vim.validate{arg1={1, 'table'}}
=> error('arg1: expected table, got number')
vim.validate{arg1={3, function(a) return (a % 2) == 0 end, 'even number'}}
=> error('arg1: expected even number, got 3')
<
Parameters: ~
{opt} Map of parameter names to validations. Each key is
a parameter name; each value is a tuple in one of
these forms:
1. (arg_value, type_name, optional)
• arg_value: argument value
• type_name: string type name, one of: ("table",
"t", "string", "s", "number", "n", "boolean",
"b", "function", "f", "nil", "thread",
"userdata")
• optional: (optional) boolean, if true, `nil`
is valid
2. (arg_value, fn, msg)
• arg_value: argument value
• fn: any function accepting one argument,
returns true if and only if the argument is
valid. Can optionally return an additional
informative error message as the second
returned value.
• msg: (optional) error string if validation
fails
==============================================================================
Lua module: uri *lua-uri*
uri_from_bufnr({bufnr}) *vim.uri_from_bufnr()*
Get a URI from a bufnr
Parameters: ~
{bufnr} (number): Buffer number
Return: ~
URI
uri_from_fname({path}) *vim.uri_from_fname()*
Get a URI from a file path.
Parameters: ~
{path} (string): Path to file
Return: ~
URI
uri_to_bufnr({uri}) *vim.uri_to_bufnr()*
Return or create a buffer for a uri.
Parameters: ~
{uri} (string): The URI
Return: ~
bufnr.
Note:
Creates buffer but does not load it
uri_to_fname({uri}) *vim.uri_to_fname()*
Get a filename from a URI
Parameters: ~
{uri} (string): The URI
Return: ~
Filename
vim:tw=78:ts=8:ft=help:norl:
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