runtime/doc/if_lua.txt - android_external_vim - Gitiles

 *if_lua.txt*    For Vim version 9.1.  Last change: 2021 Aug 06


 		  VIM REFERENCE MANUAL    by Luis Carvalho


 The Lua Interface to Vim				*lua* *Lua*

 1. Commands			|lua-commands|
 2. The vim module		|lua-vim|
 3. List userdata		|lua-list|
 4. Dict userdata		|lua-dict|
 5. Blob userdata		|lua-blob|
 6. Funcref userdata		|lua-funcref|
 7. Buffer userdata		|lua-buffer|
 8. Window userdata		|lua-window|
 9. luaeval() Vim function	|lua-luaeval|
 10. Dynamic loading		|lua-dynamic|

 {only available when Vim was compiled with the |+lua| feature}

 ==============================================================================
 1. Commands						*lua-commands*

 							*:lua*
 :[range]lua {chunk}
 			Execute Lua chunk {chunk}.

 Examples:
 >
 	:lua print("Hello, Vim!")
 	:lua local curbuf = vim.buffer() curbuf[7] = "line #7"
 <

 :[range]lua << [trim] [{endmarker}]
 {script}
 {endmarker}
 			Execute Lua script {script}.
 			Note: This command doesn't work when the Lua
 			feature wasn't compiled in.  To avoid errors, see
 			|script-here|.

 If [endmarker] is omitted from after the "<<", a dot '.' must be used after
 {script}, like for the |:append| and |:insert| commands.  Refer to
 |:let-heredoc| for more information.

 This form of the |:lua| command is mainly useful for including Lua code
 in Vim scripts.

 Example:
 >
 	function! CurrentLineInfo()
 	lua << EOF
 	local linenr = vim.window().line
 	local curline = vim.buffer()[linenr]
 	print(string.format("Current line [%d] has %d chars",
 		linenr, #curline))
 	EOF
 	endfunction
 <
 To see what version of Lua you have: >
 	:lua print(_VERSION)

 If you use LuaJIT you can also use this: >
 	:lua print(jit.version)
 <

 							*:luado*
 :[range]luado {body}	Execute Lua function "function (line, linenr) {body}
 			end" for each line in the [range], with the function
 			argument being set to the text of each line in turn,
 			without a trailing <EOL>, and the current line number.
 			If the value returned by the function is a string it
 			becomes the text of the line in the current turn. The
 			default for [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 %
 <

 All these commands execute a Lua chunk from either the command line (:lua and
 :luado) or a file (:luafile) with the given line [range]. Similarly to the Lua
 interpreter, each chunk has its own scope and so only global variables are
 shared between command calls. All Lua default libraries are available. In
 addition, Lua "print" function has its output redirected to the Vim message
 area, with arguments separated by a white space instead of a tab.

 Lua uses the "vim" module (see |lua-vim|) to issue commands to Vim
 and manage buffers (|lua-buffer|) and windows (|lua-window|). However,
 procedures that alter buffer content, open new buffers, and change cursor
 position are restricted when the command is executed in the |sandbox|.


 ==============================================================================
 2. The vim module					*lua-vim*

 Lua interfaces Vim through the "vim" module. The first and last line of the
 input range are stored in "vim.firstline" and "vim.lastline" respectively. The
 module also includes routines for buffer, window, and current line queries,
 Vim evaluation and command execution, and others.

 	vim.list([arg])		Returns an empty list or, if "arg" is a Lua
 				table with numeric keys 1, ..., n (a
 				"sequence"), returns a list l such that l[i] =
 				arg[i] for i = 1, ..., n (see |List|).
 				Non-numeric keys are not used to initialize
 				the list. See also |lua-eval| for conversion
 				rules. Example: >
 				    :lua t = {math.pi, false, say = 'hi'}
 				    :echo luaeval('vim.list(t)')
 				    :" [3.141593, v:false], 'say' is ignored
 <
 	vim.dict([arg])		Returns an empty dictionary or, if "arg" is a
 				Lua table, returns a dict d such that d[k] =
 				arg[k] for all string keys k in "arg" (see
 				|Dictionary|). Number keys are converted to
 				strings. Keys that are not strings are not
 				used to initialize the dictionary. See also
 				|lua-eval| for conversion rules. Example: >
 				    :lua t = {math.pi, false, say = 'hi'}
 				    :echo luaeval('vim.dict(t)')
 				    :" {'1': 3.141593, '2': v:false,
 				    :" 'say': 'hi'}
 <
 	vim.blob([arg])		Returns an empty blob or, if "arg" is a Lua
 				string, returns a blob b such that b is
 				equivalent to "arg" as a byte string.
 				Examples: >
 				    :lua s = "12ab\x00\x80\xfe\xff"
 				    :echo luaeval('vim.blob(s)')
 				    :" 0z31326162.0080FEFF
 <
 	vim.funcref({name})	Returns a Funcref to function {name} (see
 				|Funcref|). It is equivalent to Vim's
 				function().

 	vim.buffer([arg])	If "arg" is a number, returns buffer with
 				number "arg" in the buffer list or, if "arg"
 				is a string, returns buffer whose full or short
 				name is "arg". In both cases, returns 'nil'
 				(nil value, not string) if the buffer is not
 				found. Otherwise, if "toboolean(arg)" is
 				'true' returns the first buffer in the buffer
 				list or else the current buffer.

 	vim.window([arg])	If "arg" is a number, returns window with
 				number "arg" or 'nil' (nil value, not string)
 				if not found. Otherwise, if "toboolean(arg)"
 				is 'true' returns the first window or else the
 				current window.

 	vim.type({arg})		Returns the type of {arg}. It is equivalent to
 				Lua's "type" function, but returns "list",
 				"dict", "funcref", "buffer", or "window" if
 				{arg} is a list, dictionary, funcref, buffer,
 				or window, respectively. Examples: >
 					:lua l = vim.list()
 					:lua print(type(l), vim.type(l))
 					:" list
 <
 	vim.command({cmds})	Executes one or more lines of Ex-mode commands
 				in {cmds}.
 				Examples: >
 					:lua vim.command"set tw=60"
 					:lua vim.command"normal ddp"
 					lua << trim END
 					  vim.command([[
 					      new Myfile.js
 					      call search('start')
 					  ]])
 					END
 <
 	vim.eval({expr})	Evaluates expression {expr} (see |expression|),
 				converts the result to Lua, and returns it.
 				Vim strings and numbers are directly converted
 				to Lua strings and numbers respectively. Vim
 				lists and dictionaries are converted to Lua
 				userdata (see |lua-list| and |lua-dict|).
 				Examples: >
 					:lua tw = vim.eval"&tw"
 					:lua print(vim.eval"{'a': 'one'}".a)
 <
 	vim.line()		Returns the current line (without the trailing
 				<EOL>), a Lua string.

 	vim.beep()		Beeps.

 	vim.open({fname})	Opens a new buffer for file {fname} and
 				returns it. Note that the buffer is not set as
 				current.

 	vim.call({name} [, {args}])
 				Proxy to call Vim function named {name} with
 				arguments {args}.  Example: >
 					:lua print(vim.call('has', 'timers'))
 <
 	vim.fn			Proxy to call Vim functions. Proxy methods are
 				created on demand.  Example: >
 					:lua print(vim.fn.has('timers'))
 <
 	vim.lua_version		The Lua version Vim was compiled with, in the
 				form {major}.{minor}.{patch}, e.g. "5.1.4".

 	vim.version()		Returns a Lua table with the Vim version.
 				The table will have the following keys:
 					major - major Vim version.
 					minor - minor Vim version.
 					patch - latest patch included.

                                                         *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 Vim script
 variables from Lua.

 Example: >

     vim.g.foo = 5     -- Set the g:foo Vim script variable.
     print(vim.g.foo)  -- Get and print the g:foo Vim script variable.
     vim.g.foo = nil   -- Delete (:unlet) the Vim script 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`.

 ==============================================================================
 3. List userdata					*lua-list*

 List userdata represent vim lists, and the interface tries to follow closely
 Vim's syntax for lists. Since lists are objects, changes in list references in
 Lua are reflected in Vim and vice-versa. A list "l" has the following
 properties and methods:

 NOTE: In patch 8.2.1066 array indexes were changed from zero-based to
 one-based.  You can check with: >
 	    if has("patch-8.2.1066")

 Properties
 ----------
 	o "#l" is the number of items in list "l", equivalent to "len(l)"
 	    in Vim.
 	o "l[k]" returns the k-th item in "l"; "l" is one-indexed, as in Lua.
 	    To modify the k-th item, simply do "l[k] = newitem"; in
 	    particular, "l[k] = nil" removes the k-th item from "l". Item can
 	    be added to the end of the list by "l[#l + 1] = newitem"
 	o "l()" returns an iterator for "l".
 	o "table.insert(l, newitem)" inserts an item at the end of the list.
 	    (only Lua 5.3 and later)
 	o "table.insert(l, position, newitem)" inserts an item at the
 	    specified position. "position" is one-indexed.  (only Lua 5.3 and
 	    later)
 	o "table.remove(l, position)" removes an item at the specified
 	    position. "position" is one-indexed.


 Methods
 -------
 	o "l:add(item)" appends "item" to the end of "l".
 	o "l:insert(item[, pos])" inserts "item" at (optional)
 	    position "pos" in the list. The default value for "pos" is 0.

 Examples:
 >
 	:let l = [1, 'item']
 	:lua l = vim.eval('l') -- same 'l'
 	:lua l:add(vim.list())
 	:lua l[1] = math.pi
 	:echo l[0] " 3.141593
 	:lua l[1] = nil -- remove first item
 	:lua l:insert(true, 1)
 	:lua print(l, #l, l[1], l[2])
 	:lua l[#l + 1] = 'value'
 	:lua table.insert(l, 100)
 	:lua table.insert(l, 2, 200)
 	:lua table.remove(l, 1)
 	:lua for item in l() do print(item) end

 ==============================================================================
 4. Dict userdata					*lua-dict*

 Similarly to list userdata, dict userdata represent vim dictionaries; since
 dictionaries are also objects, references are kept between Lua and Vim. A dict
 "d" has the following properties:

 Properties
 ----------
 	o "#d" is the number of items in dict "d", equivalent to "len(d)"
 	    in Vim.
 	o "d.key" or "d['key']" returns the value at entry "key" in "d".
 	    To modify the entry at this key, simply do "d.key = newvalue"; in
 	    particular, "d.key = nil" removes the entry from "d".
 	o "d()" returns an iterator for "d" and is equivalent to "items(d)" in
 	    Vim.

 Examples:
 >
 	:let d = {'n':10}
 	:lua d = vim.eval('d') -- same 'd'
 	:lua print(d, d.n, #d)
 	:let d.self = d
 	:lua for k, v in d() do print(d, k, v) end
 	:lua d.x = math.pi
 	:lua d.self = nil -- remove entry
 	:echo d
 <

 ==============================================================================
 5. Blob userdata					*lua-blob*

 Blob userdata represent vim blobs. A blob "b" has the following properties:

 Properties
 ----------
 	o "#b" is the length of blob "b", equivalent to "len(b)" in Vim.
 	o "b[k]" returns the k-th item in "b"; "b" is zero-indexed, as in Vim.
 	    To modify the k-th item, simply do "b[k] = number"; in particular,
 	    "b[#b] = number" can append a byte to tail.

 Methods
 -------
 	o "b:add(bytes)" appends "bytes" to the end of "b".

 Examples:
 >
 	:let b = 0z001122
 	:lua b = vim.eval('b') -- same 'b'
 	:lua print(b, b[0], #b)
 	:lua b[1] = 32
 	:lua b[#b] = 0x33 -- append a byte to tail
 	:lua b:add("\x80\x81\xfe\xff")
 	:echo b
 <

 ==============================================================================
 6. Funcref userdata					*lua-funcref*

 Funcref userdata represent funcref variables in Vim. Funcrefs that were
 defined with a "dict" attribute need to be obtained as a dictionary key
 in order to have "self" properly assigned to the dictionary (see examples
 below.) A funcref "f" has the following properties:

 Properties
 ----------
 	o "#f" is the name of the function referenced by "f"
 	o "f(...)" calls the function referenced by "f" (with arguments)

 Examples:
 >
 	:function I(x)
 	:  return a:x
 	:  endfunction
 	:let R = function('I')
 	:lua i1 = vim.funcref('I')
 	:lua i2 = vim.eval('R')
 	:lua print(#i1, #i2) -- both 'I'
 	:lua print(i1, i2, #i2(i1) == #i1(i2))
 	:function Mylen() dict
 	:  return len(self.data)
 	:  endfunction
 	:let mydict = {'data': [0, 1, 2, 3]}
 	:lua d = vim.eval('mydict'); d.len = vim.funcref('Mylen')
 	:echo mydict.len()
 	:lua l = d.len -- assign d as 'self'
 	:lua print(l())
 <
 Lua functions and closures are automatically converted to a Vim |Funcref| and
 can be accessed in Vim scripts.  Example:
 >
 	lua <<EOF
 	vim.fn.timer_start(1000, function(timer)
 	    print('timer callback')
 	end)
 	EOF

 ==============================================================================
 7. Buffer userdata					*lua-buffer*

 Buffer userdata represent vim buffers. A buffer userdata "b" has the following
 properties and methods:

 Properties
 ----------
 	o "b()" sets "b" as the current buffer.
 	o "#b" is the number of lines in buffer "b".
 	o "b[k]" represents line number k: "b[k] = newline" replaces line k
 	    with string "newline" and "b[k] = nil" deletes line k.
 	o "b.name" contains the short name of buffer "b" (read-only).
 	o "b.fname" contains the full name of buffer "b" (read-only).
 	o "b.number" contains the position of buffer "b" in the buffer list
 	    (read-only).

 Methods
 -------
 	o "b:insert(newline[, pos])" inserts string "newline" at (optional)
 	    position "pos" in the buffer. The default value for "pos" is
 	    "#b + 1". If "pos == 0" then "newline" becomes the first line in
 	    the buffer.
 	o "b:next()" returns the buffer next to "b" in the buffer list.
 	o "b:previous()" returns the buffer previous to "b" in the buffer
 	    list.
 	o "b:isvalid()" returns 'true' (boolean) if buffer "b" corresponds to
 	    a "real" (not freed from memory) Vim buffer.

 Examples:
 >
 	:lua b = vim.buffer() -- current buffer
 	:lua print(b.name, b.number)
 	:lua b[1] = "first line"
 	:lua b:insert("FIRST!", 0)
 	:lua b[1] = nil -- delete top line
 	:lua for i=1,3 do b:insert(math.random()) end
 	:3,4lua for i=vim.lastline,vim.firstline,-1 do b[i] = nil end
 	:lua vim.open"myfile"() -- open buffer and set it as current

 	function! ListBuffers()
 	lua << EOF
 	local b = vim.buffer(true) -- first buffer in list
 	while b ~= nil do
 		print(b.number, b.name, #b)
 		b = b:next()
 	end
 	vim.beep()
 	EOF
 	endfunction
 <

 ==============================================================================
 8. Window userdata					*lua-window*

 Window objects represent vim windows. A window userdata "w" has the following
 properties and methods:

 Properties
 ----------
 	o "w()" sets "w" as the current window.
 	o "w.buffer" contains the buffer of window "w" (read-only).
 	o "w.line" represents the cursor line position in window "w".
 	o "w.col" represents the cursor column position in window "w".
 	o "w.width" represents the width of window "w".
 	o "w.height" represents the height of window "w".

 Methods
 -------
 	o "w:next()" returns the window next to "w".
 	o "w:previous()" returns the window previous to "w".
 	o "w:isvalid()" returns 'true' (boolean) if window "w" corresponds to
 	    a "real" (not freed from memory) Vim window.

 Examples:
 >
 	:lua w = vim.window() -- current window
 	:lua print(w.buffer.name, w.line, w.col)
 	:lua w.width = w.width + math.random(10)
 	:lua w.height = 2 * math.random() * w.height
 	:lua n,w = 0,vim.window(true) while w~=nil do n,w = n + 1,w:next() end
 	:lua print("There are " .. n .. " windows")
 <

 ==============================================================================
 9. luaeval() Vim function				*lua-luaeval* *lua-eval*

 The (dual) equivalent of "vim.eval" for passing Lua values to Vim is
 "luaeval". "luaeval" takes an expression string and an optional argument 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
 <
 Note that "_A" receives the argument to "luaeval". Lua numbers, strings, and
 list, dict, blob, and funcref userdata are converted to their Vim respective
 types, while Lua booleans are converted to numbers. An error is thrown if
 conversion of any of the remaining Lua types, including userdata other than
 lists, dicts, blobs, and funcrefs, is attempted.

 Examples: >

 	:echo luaeval('math.pi')
 	:lua a = vim.list():add('newlist')
 	:let a = luaeval('a')
 	:echo a[0] " 'newlist'
 	: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)


 ==============================================================================
 10. Dynamic loading				    *lua-dynamic*

 On MS-Windows and Unix the Lua library can be loaded dynamically.  The
 |:version| output then includes |+lua/dyn|.

 This means that Vim will search for the Lua DLL or shared library file only
 when needed.  When you don't use the Lua interface you don't need it, thus
 you can use Vim without this file.


 MS-Windows ~

 To use the Lua interface the Lua DLL must be in your search path.  In a
 console window type "path" to see what directories are used.  The 'luadll'
 option can be also used to specify the Lua DLL.  The version of the DLL must
 match the Lua version Vim was compiled with.


 Unix ~

 The 'luadll' option can be used to specify the Lua shared library file instead
 of DYNAMIC_LUA_DLL file what was specified at compile time.  The version of
 the shared library must match the Lua version Vim was compiled with.


 ==============================================================================
  vim:tw=78:ts=8:noet:ft=help:norl:
	if_lua.txt For Vim version 9.1. Last change: 2021 Aug 06


	VIM REFERENCE MANUAL by Luis Carvalho


	The Lua Interface to Vim lua Lua

	1. Commands \|lua-commands\|
	2. The vim module \|lua-vim\|
	3. List userdata \|lua-list\|
	4. Dict userdata \|lua-dict\|
	5. Blob userdata \|lua-blob\|
	6. Funcref userdata \|lua-funcref\|
	7. Buffer userdata \|lua-buffer\|
	8. Window userdata \|lua-window\|
	9. luaeval() Vim function \|lua-luaeval\|
	10. Dynamic loading \|lua-dynamic\|

	{only available when Vim was compiled with the \|+lua\| feature}

	==============================================================================
	1. Commands lua-commands

	:lua
	:[range]lua {chunk}
	Execute Lua chunk {chunk}.

	Examples:
	>
	:lua print("Hello, Vim!")
	:lua local curbuf = vim.buffer() curbuf[7] = "line #7"
	<

	:[range]lua << [trim] [{endmarker}]
	{script}
	{endmarker}
	Execute Lua script {script}.
	Note: This command doesn't work when the Lua
	feature wasn't compiled in. To avoid errors, see
	\|script-here\|.

	If [endmarker] is omitted from after the "<<", a dot '.' must be used after
	{script}, like for the \|:append\| and \|:insert\| commands. Refer to
	\|:let-heredoc\| for more information.

	This form of the \|:lua\| command is mainly useful for including Lua code
	in Vim scripts.

	Example:
	>
	function! CurrentLineInfo()
	lua << EOF
	local linenr = vim.window().line
	local curline = vim.buffer()[linenr]
	print(string.format("Current line [%d] has %d chars",
	linenr, #curline))
	EOF
	endfunction
	<
	To see what version of Lua you have: >
	:lua print(_VERSION)

	If you use LuaJIT you can also use this: >
	:lua print(jit.version)
	<

	:luado
	:[range]luado {body} Execute Lua function "function (line, linenr) {body}
	end" for each line in the [range], with the function
	argument being set to the text of each line in turn,
	without a trailing <EOL>, and the current line number.
	If the value returned by the function is a string it
	becomes the text of the line in the current turn. The
	default for [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 %
	<

	All these commands execute a Lua chunk from either the command line (:lua and
	:luado) or a file (:luafile) with the given line [range]. Similarly to the Lua
	interpreter, each chunk has its own scope and so only global variables are
	shared between command calls. All Lua default libraries are available. In
	addition, Lua "print" function has its output redirected to the Vim message
	area, with arguments separated by a white space instead of a tab.

	Lua uses the "vim" module (see \|lua-vim\|) to issue commands to Vim
	and manage buffers (\|lua-buffer\|) and windows (\|lua-window\|). However,
	procedures that alter buffer content, open new buffers, and change cursor
	position are restricted when the command is executed in the \|sandbox\|.


	==============================================================================
	2. The vim module lua-vim

	Lua interfaces Vim through the "vim" module. The first and last line of the
	input range are stored in "vim.firstline" and "vim.lastline" respectively. The
	module also includes routines for buffer, window, and current line queries,
	Vim evaluation and command execution, and others.

	vim.list([arg]) Returns an empty list or, if "arg" is a Lua
	table with numeric keys 1, ..., n (a
	"sequence"), returns a list l such that l[i] =
	arg[i] for i = 1, ..., n (see \|List\|).
	Non-numeric keys are not used to initialize
	the list. See also \|lua-eval\| for conversion
	rules. Example: >
	:lua t = {math.pi, false, say = 'hi'}
	:echo luaeval('vim.list(t)')
	:" [3.141593, v:false], 'say' is ignored
	<
	vim.dict([arg]) Returns an empty dictionary or, if "arg" is a
	Lua table, returns a dict d such that d[k] =
	arg[k] for all string keys k in "arg" (see
	\|Dictionary\|). Number keys are converted to
	strings. Keys that are not strings are not
	used to initialize the dictionary. See also
	\|lua-eval\| for conversion rules. Example: >
	:lua t = {math.pi, false, say = 'hi'}
	:echo luaeval('vim.dict(t)')
	:" {'1': 3.141593, '2': v:false,
	:" 'say': 'hi'}
	<
	vim.blob([arg]) Returns an empty blob or, if "arg" is a Lua
	string, returns a blob b such that b is
	equivalent to "arg" as a byte string.
	Examples: >
	:lua s = "12ab\x00\x80\xfe\xff"
	:echo luaeval('vim.blob(s)')
	:" 0z31326162.0080FEFF
	<
	vim.funcref({name}) Returns a Funcref to function {name} (see
	\|Funcref\|). It is equivalent to Vim's
	function().

	vim.buffer([arg]) If "arg" is a number, returns buffer with
	number "arg" in the buffer list or, if "arg"
	is a string, returns buffer whose full or short
	name is "arg". In both cases, returns 'nil'
	(nil value, not string) if the buffer is not
	found. Otherwise, if "toboolean(arg)" is
	'true' returns the first buffer in the buffer
	list or else the current buffer.

	vim.window([arg]) If "arg" is a number, returns window with
	number "arg" or 'nil' (nil value, not string)
	if not found. Otherwise, if "toboolean(arg)"
	is 'true' returns the first window or else the
	current window.

	vim.type({arg}) Returns the type of {arg}. It is equivalent to
	Lua's "type" function, but returns "list",
	"dict", "funcref", "buffer", or "window" if
	{arg} is a list, dictionary, funcref, buffer,
	or window, respectively. Examples: >
	:lua l = vim.list()
	:lua print(type(l), vim.type(l))
	:" list
	<
	vim.command({cmds}) Executes one or more lines of Ex-mode commands
	in {cmds}.
	Examples: >
	:lua vim.command"set tw=60"
	:lua vim.command"normal ddp"
	lua << trim END
	vim.command([[
	new Myfile.js
	call search('start')
	]])
	END
	<
	vim.eval({expr}) Evaluates expression {expr} (see \|expression\|),
	converts the result to Lua, and returns it.
	Vim strings and numbers are directly converted
	to Lua strings and numbers respectively. Vim
	lists and dictionaries are converted to Lua
	userdata (see \|lua-list\| and \|lua-dict\|).
	Examples: >
	:lua tw = vim.eval"&tw"
	:lua print(vim.eval"{'a': 'one'}".a)
	<
	vim.line() Returns the current line (without the trailing
	<EOL>), a Lua string.

	vim.beep() Beeps.

	vim.open({fname}) Opens a new buffer for file {fname} and
	returns it. Note that the buffer is not set as
	current.

	vim.call({name} [, {args}])
	Proxy to call Vim function named {name} with
	arguments {args}. Example: >
	:lua print(vim.call('has', 'timers'))
	<
	vim.fn Proxy to call Vim functions. Proxy methods are
	created on demand. Example: >
	:lua print(vim.fn.has('timers'))
	<
	vim.lua_version The Lua version Vim was compiled with, in the
	form {major}.{minor}.{patch}, e.g. "5.1.4".

	vim.version() Returns a Lua table with the Vim version.
	The table will have the following keys:
	major - major Vim version.
	minor - minor Vim version.
	patch - latest patch included.

	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 Vim script
	variables from Lua.

	Example: >

	vim.g.foo = 5 -- Set the g:foo Vim script variable.
	print(vim.g.foo) -- Get and print the g:foo Vim script variable.
	vim.g.foo = nil -- Delete (:unlet) the Vim script 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`.

	==============================================================================
	3. List userdata lua-list

	List userdata represent vim lists, and the interface tries to follow closely
	Vim's syntax for lists. Since lists are objects, changes in list references in
	Lua are reflected in Vim and vice-versa. A list "l" has the following
	properties and methods:

	NOTE: In patch 8.2.1066 array indexes were changed from zero-based to
	one-based. You can check with: >
	if has("patch-8.2.1066")

	Properties
	----------
	o "#l" is the number of items in list "l", equivalent to "len(l)"
	in Vim.
	o "l[k]" returns the k-th item in "l"; "l" is one-indexed, as in Lua.
	To modify the k-th item, simply do "l[k] = newitem"; in
	particular, "l[k] = nil" removes the k-th item from "l". Item can
	be added to the end of the list by "l[#l + 1] = newitem"
	o "l()" returns an iterator for "l".
	o "table.insert(l, newitem)" inserts an item at the end of the list.
	(only Lua 5.3 and later)
	o "table.insert(l, position, newitem)" inserts an item at the
	specified position. "position" is one-indexed. (only Lua 5.3 and
	later)
	o "table.remove(l, position)" removes an item at the specified
	position. "position" is one-indexed.


	Methods
	-------
	o "l:add(item)" appends "item" to the end of "l".
	o "l:insert(item[, pos])" inserts "item" at (optional)
	position "pos" in the list. The default value for "pos" is 0.

	Examples:
	>
	:let l = [1, 'item']
	:lua l = vim.eval('l') -- same 'l'
	:lua l:add(vim.list())
	:lua l[1] = math.pi
	:echo l[0] " 3.141593
	:lua l[1] = nil -- remove first item
	:lua l:insert(true, 1)
	:lua print(l, #l, l[1], l[2])
	:lua l[#l + 1] = 'value'
	:lua table.insert(l, 100)
	:lua table.insert(l, 2, 200)
	:lua table.remove(l, 1)
	:lua for item in l() do print(item) end

	==============================================================================
	4. Dict userdata lua-dict

	Similarly to list userdata, dict userdata represent vim dictionaries; since
	dictionaries are also objects, references are kept between Lua and Vim. A dict
	"d" has the following properties:

	Properties
	----------
	o "#d" is the number of items in dict "d", equivalent to "len(d)"
	in Vim.
	o "d.key" or "d['key']" returns the value at entry "key" in "d".
	To modify the entry at this key, simply do "d.key = newvalue"; in
	particular, "d.key = nil" removes the entry from "d".
	o "d()" returns an iterator for "d" and is equivalent to "items(d)" in
	Vim.

	Examples:
	>
	:let d = {'n':10}
	:lua d = vim.eval('d') -- same 'd'
	:lua print(d, d.n, #d)
	:let d.self = d
	:lua for k, v in d() do print(d, k, v) end
	:lua d.x = math.pi
	:lua d.self = nil -- remove entry
	:echo d
	<

	==============================================================================
	5. Blob userdata lua-blob

	Blob userdata represent vim blobs. A blob "b" has the following properties:

	Properties
	----------
	o "#b" is the length of blob "b", equivalent to "len(b)" in Vim.
	o "b[k]" returns the k-th item in "b"; "b" is zero-indexed, as in Vim.
	To modify the k-th item, simply do "b[k] = number"; in particular,
	"b[#b] = number" can append a byte to tail.

	Methods
	-------
	o "b:add(bytes)" appends "bytes" to the end of "b".

	Examples:
	>
	:let b = 0z001122
	:lua b = vim.eval('b') -- same 'b'
	:lua print(b, b[0], #b)
	:lua b[1] = 32
	:lua b[#b] = 0x33 -- append a byte to tail
	:lua b:add("\x80\x81\xfe\xff")
	:echo b
	<

	==============================================================================
	6. Funcref userdata lua-funcref

	Funcref userdata represent funcref variables in Vim. Funcrefs that were
	defined with a "dict" attribute need to be obtained as a dictionary key
	in order to have "self" properly assigned to the dictionary (see examples
	below.) A funcref "f" has the following properties:

	Properties
	----------
	o "#f" is the name of the function referenced by "f"
	o "f(...)" calls the function referenced by "f" (with arguments)

	Examples:
	>
	:function I(x)
	: return a:x
	: endfunction
	:let R = function('I')
	:lua i1 = vim.funcref('I')
	:lua i2 = vim.eval('R')
	:lua print(#i1, #i2) -- both 'I'
	:lua print(i1, i2, #i2(i1) == #i1(i2))
	:function Mylen() dict
	: return len(self.data)
	: endfunction
	:let mydict = {'data': [0, 1, 2, 3]}
	:lua d = vim.eval('mydict'); d.len = vim.funcref('Mylen')
	:echo mydict.len()
	:lua l = d.len -- assign d as 'self'
	:lua print(l())
	<
	Lua functions and closures are automatically converted to a Vim \|Funcref\| and
	can be accessed in Vim scripts. Example:
	>
	lua <<EOF
	vim.fn.timer_start(1000, function(timer)
	print('timer callback')
	end)
	EOF

	==============================================================================
	7. Buffer userdata lua-buffer

	Buffer userdata represent vim buffers. A buffer userdata "b" has the following
	properties and methods:

	Properties
	----------
	o "b()" sets "b" as the current buffer.
	o "#b" is the number of lines in buffer "b".
	o "b[k]" represents line number k: "b[k] = newline" replaces line k
	with string "newline" and "b[k] = nil" deletes line k.
	o "b.name" contains the short name of buffer "b" (read-only).
	o "b.fname" contains the full name of buffer "b" (read-only).
	o "b.number" contains the position of buffer "b" in the buffer list
	(read-only).

	Methods
	-------
	o "b:insert(newline[, pos])" inserts string "newline" at (optional)
	position "pos" in the buffer. The default value for "pos" is
	"#b + 1". If "pos == 0" then "newline" becomes the first line in
	the buffer.
	o "b:next()" returns the buffer next to "b" in the buffer list.
	o "b:previous()" returns the buffer previous to "b" in the buffer
	list.
	o "b:isvalid()" returns 'true' (boolean) if buffer "b" corresponds to
	a "real" (not freed from memory) Vim buffer.

	Examples:
	>
	:lua b = vim.buffer() -- current buffer
	:lua print(b.name, b.number)
	:lua b[1] = "first line"
	:lua b:insert("FIRST!", 0)
	:lua b[1] = nil -- delete top line
	:lua for i=1,3 do b:insert(math.random()) end
	:3,4lua for i=vim.lastline,vim.firstline,-1 do b[i] = nil end
	:lua vim.open"myfile"() -- open buffer and set it as current

	function! ListBuffers()
	lua << EOF
	local b = vim.buffer(true) -- first buffer in list
	while b ~= nil do
	print(b.number, b.name, #b)
	b = b:next()
	end
	vim.beep()
	EOF
	endfunction
	<

	==============================================================================
	8. Window userdata lua-window

	Window objects represent vim windows. A window userdata "w" has the following
	properties and methods:

	Properties
	----------
	o "w()" sets "w" as the current window.
	o "w.buffer" contains the buffer of window "w" (read-only).
	o "w.line" represents the cursor line position in window "w".
	o "w.col" represents the cursor column position in window "w".
	o "w.width" represents the width of window "w".
	o "w.height" represents the height of window "w".

	Methods
	-------
	o "w:next()" returns the window next to "w".
	o "w:previous()" returns the window previous to "w".
	o "w:isvalid()" returns 'true' (boolean) if window "w" corresponds to
	a "real" (not freed from memory) Vim window.

	Examples:
	>
	:lua w = vim.window() -- current window
	:lua print(w.buffer.name, w.line, w.col)
	:lua w.width = w.width + math.random(10)
	:lua w.height = 2 * math.random() * w.height
	:lua n,w = 0,vim.window(true) while w~=nil do n,w = n + 1,w:next() end
	:lua print("There are " .. n .. " windows")
	<

	==============================================================================
	9. luaeval() Vim function lua-luaeval lua-eval

	The (dual) equivalent of "vim.eval" for passing Lua values to Vim is
	"luaeval". "luaeval" takes an expression string and an optional argument 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
	<
	Note that "_A" receives the argument to "luaeval". Lua numbers, strings, and
	list, dict, blob, and funcref userdata are converted to their Vim respective
	types, while Lua booleans are converted to numbers. An error is thrown if
	conversion of any of the remaining Lua types, including userdata other than
	lists, dicts, blobs, and funcrefs, is attempted.

	Examples: >

	:echo luaeval('math.pi')
	:lua a = vim.list():add('newlist')
	:let a = luaeval('a')
	:echo a[0] " 'newlist'
	: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)


	==============================================================================
	10. Dynamic loading lua-dynamic

	On MS-Windows and Unix the Lua library can be loaded dynamically. The
	\|:version\| output then includes \|+lua/dyn\|.

	This means that Vim will search for the Lua DLL or shared library file only
	when needed. When you don't use the Lua interface you don't need it, thus
	you can use Vim without this file.


	MS-Windows ~

	To use the Lua interface the Lua DLL must be in your search path. In a
	console window type "path" to see what directories are used. The 'luadll'
	option can be also used to specify the Lua DLL. The version of the DLL must
	match the Lua version Vim was compiled with.


	Unix ~

	The 'luadll' option can be used to specify the Lua shared library file instead
	of DYNAMIC_LUA_DLL file what was specified at compile time. The version of
	the shared library must match the Lua version Vim was compiled with.


	==============================================================================
	vim:tw=78:ts=8:noet:ft=help:norl: