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diff --git a/runtime/doc/if_lua.txt b/runtime/doc/if_lua.txt new file mode 100644 index 0000000000..932564170d --- /dev/null +++ b/runtime/doc/if_lua.txt @@ -0,0 +1,174 @@ +*if_lua.txt* For Neovim + + + VIM REFERENCE MANUAL by Luis Carvalho + + +The Lua Interface to Vim *lua* *Lua* + +1. Commands |lua-commands| +2. The vim module |lua-vim| +3. The luaeval function |lua-luaeval| + +============================================================================== +1. Commands *lua-commands* + + *:lua* +:[range]lua {chunk} + Execute Lua chunk {chunk}. {not in Vi} + +Examples: +> + :lua vim.api.nvim_command('echo "Hello, Neovim!"') +< + +:[range]lua << {endmarker} +{script} +{endmarker} + Execute Lua script {script}. {not in Vi} + Note: This command doesn't work when the Lua + feature wasn't compiled in. To avoid errors, see + |script-here|. + +{endmarker} must NOT be preceded by any white space. If {endmarker} is +omitted from after the "<<", a dot '.' must be used after {script}, like +for the |:append| and |:insert| commands. +This form of the |:lua| command is mainly useful for including Lua code +in Vim scripts. + +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 in example variables are prefixed with local: they will disappear +when block finishes. This is not the case for globals. + +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,$". + {not in Vi} + +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}. {not in Vi} + 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 Neovim +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. Currently it only has `api` +submodule which is a table with all API functions. Descriptions of these +functions may be found in |api-funcs.txt|. + +============================================================================== +3. The luaeval function *lua-luaeval* *lua-eval* + *luaeval()* + +The (dual) equivalent of "vim.eval" for passing Lua values to Vim 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 + +Note that "_A" receives the argument to "luaeval". Lua nils, numbers, strings, +tables and booleans are converted to their Vim respective types. An error is +thrown if conversion of any of the remaining Lua types is attempted. + +Note 2: lua tables are used as both dictionaries and lists, thus making it +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|. +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 that currently second argument to `luaeval` undergoes VimL to lua +conversion, so changing containers in lua do not affect values in VimL. Return +value is also always converted. When converting, |msgpack-special-dict|s are +treated specially. + +============================================================================== + vim:tw=78:ts=8:noet:ft=help:norl: |