Mercurial > vim
view runtime/doc/if_lua.txt @ 32936:c517845bd10e v9.0.1776
patch 9.0.1776: No support for stable Python 3 ABI
Commit: https://github.com/vim/vim/commit/c13b3d1350b60b94fe87f0761ea31c0e7fb6ebf3
Author: Yee Cheng Chin <ychin.git@gmail.com>
Date: Sun Aug 20 21:18:38 2023 +0200
patch 9.0.1776: No support for stable Python 3 ABI
Problem: No support for stable Python 3 ABI
Solution: Support Python 3 stable ABI
Commits:
1) Support Python 3 stable ABI to allow mixed version interoperatbility
Vim currently supports embedding Python for use with plugins, and the
"dynamic" linking option allows the user to specify a locally installed
version of Python by setting `pythonthreedll`. However, one caveat is
that the Python 3 libs are not binary compatible across minor versions,
and mixing versions can potentially be dangerous (e.g. let's say Vim was
linked against the Python 3.10 SDK, but the user sets `pythonthreedll`
to a 3.11 lib). Usually, nothing bad happens, but in theory this could
lead to crashes, memory corruption, and other unpredictable behaviors.
It's also difficult for the user to tell something is wrong because Vim
has no way of reporting what Python 3 version Vim was linked with.
For Vim installed via a package manager, this usually isn't an issue
because all the dependencies would already be figured out. For prebuilt
Vim binaries like MacVim (my motivation for working on this), AppImage,
and Win32 installer this could potentially be an issue as usually a
single binary is distributed. This is more tricky when a new Python
version is released, as there's a chicken-and-egg issue with deciding
what Python version to build against and hard to keep in sync when a new
Python version just drops and we have a mix of users of different Python
versions, and a user just blindly upgrading to a new Python could lead to
bad interactions with Vim.
Python 3 does have a solution for this problem: stable ABI / limited API
(see https://docs.python.org/3/c-api/stable.html). The C SDK limits the
API to a set of functions that are promised to be stable across
versions. This pull request adds an ifdef config that allows us to turn
it on when building Vim. Vim binaries built with this option should be
safe to freely link with any Python 3 libraies without having the
constraint of having to use the same minor version.
Note: Python 2 has no such concept and this doesn't change how Python 2
integration works (not that there is going to be a new version of Python
2 that would cause compatibility issues in the future anyway).
---
Technical details:
======
The stable ABI can be accessed when we compile with the Python 3 limited
API (by defining `Py_LIMITED_API`). The Python 3 code (in `if_python3.c`
and `if_py_both.h`) would now handle this and switch to limited API
mode. Without it set, Vim will still use the full API as before so this
is an opt-in change.
The main difference is that `PyType_Object` is now an opaque struct that
we can't directly create "static types" out of, and we have to create
type objects as "heap types" instead. This is because the struct is not
stable and changes from version to version (e.g. 3.8 added a
`tp_vectorcall` field to it). I had to change all the types to be
allocated on the heap instead with just a pointer to them.
Other functions are also simply missing in limited API, or they are
introduced too late (e.g. `PyUnicode_AsUTF8AndSize` in 3.10) to it that
we need some other ways to do the same thing, so I had to abstract a few
things into macros, and sometimes re-implement functions like
`PyObject_NEW`.
One caveat is that in limited API, `OutputType` (used for replacing
`sys.stdout`) no longer inherits from `PyStdPrinter_Type` which I don't
think has any real issue other than minor differences in how they
convert to a string and missing a couple functions like `mode()` and
`fileno()`.
Also fixed an existing bug where `tp_basicsize` was set incorrectly for
`BufferObject`, `TabListObject, `WinListObject`.
Technically, there could be a small performance drop, there is a little
more indirection with accessing type objects, and some APIs like
`PyUnicode_AsUTF8AndSize` are missing, but in practice I didn't see any
difference, and any well-written Python plugin should try to avoid
excessing callbacks to the `vim` module in Python anyway.
I only tested limited API mode down to Python 3.7, which seemes to
compile and work fine. I haven't tried earlier Python versions.
2) Fix PyIter_Check on older Python vers / type##Ptr unused warning
For PyIter_Check, older versions exposed them as either macros (used in
full API), or a function (for use in limited API). A previous change
exposed PyIter_Check to the dynamic build because Python just moved it
to function-only in 3.10 anyway. Because of that, just make sure we
always grab the function in dynamic builds in earlier versions since
that's what Python eventually did anyway.
3) Move Py_LIMITED_API define to configure script
Can now use --with-python-stable-abi flag to customize what stable ABI
version to target. Can also use an env var to do so as well.
4) Show +python/dyn-stable in :version, and allow has() feature query
Not sure if the "/dyn-stable" suffix would break things, or whether we
should do it another way. Or just don't show it in version and rely on
has() feature checking.
5) Documentation first draft. Still need to implement v:python3_version
6) Fix PyIter_Check build breaks when compiling against Python 3.8
7) Add CI coverage stable ABI on Linux/Windows / make configurable on Windows
This adds configurable options for Windows make files (both MinGW and
MSVC). CI will also now exercise both traditional full API and stable
ABI for Linux and Windows in the matrix for coverage.
Also added a "dynamic" option to Linux matrix as a drive-by change to
make other scripting languages like Ruby / Perl testable under both
static and dynamic builds.
8) Fix inaccuracy in Windows docs
Python's own docs are confusing but you don't actually want to use
`python3.dll` for the dynamic linkage.
9) Add generated autoconf file
10) Add v:python3_version support
This variable indicates the version of Python3 that Vim was built
against (PY_VERSION_HEX), and will be useful to check whether the Python
library you are loading in dynamically actually fits it. When built with
stable ABI, it will be the limited ABI version instead
(`Py_LIMITED_API`), which indicates the minimum version of Python 3 the
user should have, rather than the exact match. When stable ABI is used,
we won't be exposing PY_VERSION_HEX in this var because it just doesn't
seem necessary to do so (the whole point of stable ABI is the promise
that it will work across versions), and I don't want to confuse the user
with too many variables.
Also, cleaned up some documentation, and added help tags.
11) Fix Python 3.7 compat issues
Fix a couple issues when using limited API < 3.8
- Crash on exit: In Python 3.7, if a heap-allocated type is destroyed
before all instances are, it would cause a crash later. This happens
when we destroyed `OptionsType` before calling `Py_Finalize` when
using the limited API. To make it worse, later versions changed the
semantics and now each instance has a strong reference to its own type
and the recommendation has changed to have each instance de-ref its
own type and have its type in GC traversal. To avoid dealing with
these cross-version variations, we just don't free the heap type. They
are static types in non-limited-API anyway and are designed to last
through the entirety of the app, and we also don't restart the Python
runtime and therefore do not need it to have absolutely 0 leaks.
See:
- https://docs.python.org/3/whatsnew/3.8.html#changes-in-the-c-api
- https://docs.python.org/3/whatsnew/3.9.html#changes-in-the-c-api
- PyIter_Check: This function is not provided in limited APIs older than
3.8. Previously I was trying to mock it out using manual
PyType_GetSlot() but it was brittle and also does not actually work
properly for static types (it will generate a Python error). Just
return false. It does mean using limited API < 3.8 is not recommended
as you lose the functionality to handle iterators, but from playing
with plugins I couldn't find it to be an issue.
- Fix loading of PyIter_Check so it will be done when limited API < 3.8.
Otherwise loading a 3.7 Python lib will fail even if limited API was
specified to use it.
12) Make sure to only load `PyUnicode_AsUTF8AndSize` in needed in limited API
We don't use this function unless limited API >= 3.10, but we were
loading it regardless. Usually it's ok in Unix-like systems where Python
just has a single lib that we load from, but in Windows where there is a
separate python3.dll this would not work as the symbol would not have
been exposed in this more limited DLL file. This makes it much clearer
under what condition is this function needed.
closes: #12032
Signed-off-by: Christian Brabandt <cb@256bit.org>
Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Sun, 20 Aug 2023 21:30:04 +0200 |
parents | f8116058ca76 |
children | 4635e43f2c6f |
line wrap: on
line source
*if_lua.txt* For Vim version 9.0. 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: