view runtime/doc/if_perl.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 695b50472e85
children 897f3ed27be2
line wrap: on
line source

*if_perl.txt*   For Vim version 9.0.  Last change: 2023 May 14


		  VIM REFERENCE MANUAL    by Sven Verdoolaege
					 and Matt Gerassimof

Perl and Vim				*perl* *Perl*

1. Editing Perl files			|perl-editing|
2. Compiling Vim with Perl interface	|perl-compiling|
3. Using the Perl interface		|perl-using|
4. Dynamic loading			|perl-dynamic|

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

==============================================================================
1. Editing Perl files					*perl-editing*

Vim syntax highlighting supports Perl and POD files.  Vim assumes a file is
Perl code if the filename has a .pl or .pm suffix.  Vim also examines the first
line of a file, regardless of the filename suffix, to check if a file is a
Perl script (see scripts.vim in Vim's syntax directory).  Vim assumes a file
is POD text if the filename has a .POD suffix.

To use tags with Perl, you need Universal/Exuberant Ctags.  Look here:
	Universal Ctags (preferred): https://ctags.io
	Exuberant Ctags: http://ctags.sourceforge.net

Alternatively, you can use the Perl script pltags.pl, which is shipped with
Vim in the $VIMRUNTIME/tools directory.  This script has currently more
features than Exuberant ctags' Perl support.

==============================================================================
2. Compiling Vim with Perl interface			*perl-compiling*

To compile Vim with Perl interface, you need Perl 5.004 (or later).  Perl must
be installed before you compile Vim.  Vim's Perl interface does NOT work with
the 5.003 version that has been officially released!  It will probably work
with Perl 5.003_05 and later.

The Perl patches for Vim were made by:
	Sven Verdoolaege <skimo@breughel.ufsia.ac.be>
	Matt Gerassimof

Perl for MS-Windows (and other platforms) can be found at:
	http://www.perl.org/
The ActiveState one should work, Strawberry Perl is a good alternative.

==============================================================================
3. Using the Perl interface				*perl-using*

							*:perl* *:pe*
:pe[rl] {cmd}		Execute Perl command {cmd}.  The current package
			is "main".  Simple example to test if `:perl` is
			working: >
				:perl VIM::Msg("Hello")

:pe[rl] << [trim] [{endmarker}]
{script}
{endmarker}
			Execute Perl script {script}.
			The {endmarker} after {script} must NOT be preceded by
			any white space.

			If [endmarker] is omitted, it defaults to a dot '.'
			like for the |:append| and |:insert| commands.  Using
			'.' helps when inside a function, because "$i;" looks
			like the start of an |:insert| command to Vim.

			This form of the |:perl| command is mainly useful for
			including perl code in vim scripts.
			Note: This command doesn't work when the Perl feature
			wasn't compiled in.  To avoid errors, see
			|script-here|.


Example vim script: >

	function! WhitePearl()
	perl << EOF
		VIM::Msg("pearls are nice for necklaces");
		VIM::Msg("rubys for rings");
		VIM::Msg("pythons for bags");
		VIM::Msg("tcls????");
	EOF
	endfunction
<
To see what version of Perl you have: >
	:perl print $^V
<

							*:perldo* *:perld*
:[range]perld[o] {cmd}	Execute Perl command {cmd} for each line in the
			[range], with $_ being set to the text of each line in
			turn, without a trailing <EOL>.  Setting $_ will change
			the text, but note that it is not possible to add or
			delete lines using this command.
			The default for [range] is the whole file: "1,$".

Here are some things you can try: >

  :perl $a=1
  :perldo $_ = reverse($_);1
  :perl VIM::Msg("hello")
  :perl $line = $curbuf->Get(42)
<							*E299*
Executing Perl commands in the |sandbox| is limited.  ":perldo" will not be
possible at all.  ":perl" will be evaluated in the Safe environment, if
possible.


							*perl-overview*
Here is an overview of the functions that are available to Perl: >

  :perl VIM::Msg("Text")		# displays a message
  :perl VIM::Msg("Wrong!", "ErrorMsg")	# displays an error message
  :perl VIM::Msg("remark", "Comment")	# displays a highlighted message
  :perl VIM::SetOption("ai")		# sets a vim option
  :perl $nbuf = VIM::Buffers()		# returns the number of buffers
  :perl @buflist = VIM::Buffers()	# returns array of all buffers
  :perl $mybuf = (VIM::Buffers('qq.c'))[0] # returns buffer object for 'qq.c'
  :perl @winlist = VIM::Windows()	# returns array of all windows
  :perl $nwin = VIM::Windows()		# returns the number of windows
  :perl ($success, $v) = VIM::Eval('&path') # $v: option 'path', $success: 1
  :perl ($success, $v) = VIM::Eval('&xyz')  # $v: '' and $success: 0
  :perl $v = VIM::Eval('expand("<cfile>")') # expands <cfile>
  :perl $curwin->SetHeight(10)		# sets the window height
  :perl @pos = $curwin->Cursor()	# returns (row, col) array
  :perl @pos = (10, 10)
  :perl $curwin->Cursor(@pos)		# sets cursor to @pos
  :perl $curwin->Cursor(10,10)		# sets cursor to row 10 col 10
  :perl $mybuf = $curwin->Buffer()	# returns the buffer object for window
  :perl $curbuf->Name()			# returns buffer name
  :perl $curbuf->Number()		# returns buffer number
  :perl $curbuf->Count()		# returns the number of lines
  :perl $l = $curbuf->Get(10)		# returns line 10
  :perl @l = $curbuf->Get(1 .. 5)	# returns lines 1 through 5
  :perl $curbuf->Delete(10)		# deletes line 10
  :perl $curbuf->Delete(10, 20)		# delete lines 10 through 20
  :perl $curbuf->Append(10, "Line")	# appends a line
  :perl $curbuf->Append(10, "Line1", "Line2", "Line3") # appends 3 lines
  :perl @l = ("L1", "L2", "L3")
  :perl $curbuf->Append(10, @l)		# appends L1, L2 and L3
  :perl $curbuf->Set(10, "Line")	# replaces line 10
  :perl $curbuf->Set(10, "Line1", "Line2")	# replaces lines 10 and 11
  :perl $curbuf->Set(10, @l)		# replaces 3 lines
<
							*perl-Msg*
VIM::Msg({msg}, {group}?)
			Displays the message {msg}.  The optional {group}
			argument specifies a highlight group for Vim to use
			for the message.

							*perl-SetOption*
VIM::SetOption({arg})	Sets a vim option.  {arg} can be any argument that the
			":set" command accepts.  Note that this means that no
			spaces are allowed in the argument!  See |:set|.

							*perl-Buffers*
VIM::Buffers([{bn}...])	With no arguments, returns a list of all the buffers
			in an array context or returns the number of buffers
			in a scalar context.  For a list of buffer names or
			numbers {bn}, returns a list of the buffers matching
			{bn}, using the same rules as Vim's internal
			|bufname()| function.
			WARNING: the list becomes invalid when |:bwipe| is
			used.  Using it anyway may crash Vim.

							*perl-Windows*
VIM::Windows([{wn}...])	With no arguments, returns a list of all the windows
			in an array context or returns the number of windows
			in a scalar context.  For a list of window numbers
			{wn}, returns a list of the windows with those
			numbers.
			WARNING: the list becomes invalid when a window is
			closed.  Using it anyway may crash Vim.

							*perl-DoCommand*
VIM::DoCommand({cmd})	Executes Ex command {cmd}.

							*perl-Eval*
VIM::Eval({expr})	Evaluates {expr} and returns (success, value) in list
			context or just value in scalar context.
			success=1 indicates that val contains the value of
			{expr}; success=0 indicates a failure to evaluate
			the expression.  '@x' returns the contents of register
			x, '&x' returns the value of option x, 'x' returns the
			value of internal |variables| x, and '$x' is equivalent
			to perl's $ENV{x}.  All |functions| accessible from
			the command-line are valid for {expr}.
			A |List| is turned into a string by joining the items
			and inserting line breaks.

							*perl-Blob*
VIM::Blob({expr})	Return |Blob| literal string 0zXXXX from scalar value.

							*perl-SetHeight*
Window->SetHeight({height})
			Sets the Window height to {height}, within screen
			limits.

							*perl-GetCursor*
Window->Cursor({row}?, {col}?)
			With no arguments, returns a (row, col) array for the
			current cursor position in the Window.  With {row} and
			{col} arguments, sets the Window's cursor position to
			{row} and {col}.  Note that {col} is numbered from 0,
			Perl-fashion, and thus is one less than the value in
			Vim's ruler.

Window->Buffer()					*perl-Buffer*
			Returns the Buffer object corresponding to the given
			Window.

							*perl-Name*
Buffer->Name()		Returns the filename for the Buffer.

							*perl-Number*
Buffer->Number()	Returns the number of the Buffer.

							*perl-Count*
Buffer->Count()		Returns the number of lines in the Buffer.

							*perl-Get*
Buffer->Get({lnum}, {lnum}?, ...)
			Returns a text string of line {lnum} in the Buffer
			for each {lnum} specified.  An array can be passed
			with a list of {lnum}'s specified.

							*perl-Delete*
Buffer->Delete({lnum}, {lnum}?)
			Deletes line {lnum} in the Buffer.  With the second
			{lnum}, deletes the range of lines from the first
			{lnum} to the second {lnum}.

							*perl-Append*
Buffer->Append({lnum}, {line}, {line}?, ...)
			Appends each {line} string after Buffer line {lnum}.
			The list of {line}s can be an array.

							*perl-Set*
Buffer->Set({lnum}, {line}, {line}?, ...)
			Replaces one or more Buffer lines with specified
			{lines}s, starting at Buffer line {lnum}.  The list of
			{line}s can be an array.  If the arguments are
			invalid, replacement does not occur.

$main::curwin
			The current window object.

$main::curbuf
			The current buffer object.


							*script-here*
When using a script language in-line, you might want to skip this when the
language isn't supported.  >
   if has('perl')
     perl << EOF
       print 'perl works'
   EOF
   endif
Note that "EOF" must be at the start of the line without preceding white
space.

==============================================================================
4. Dynamic loading					*perl-dynamic*

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

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


MS-Windows ~

You can download Perl from http://www.perl.org.  The one from ActiveState was
used for building Vim.

To use the Perl interface the Perl DLL must be in your search path.
If Vim reports it cannot find the perl512.dll, make sure your $PATH includes
the directory where it is located.  The Perl installer normally does that.
In a console window type "path" to see what directories are used.  The
'perldll' option can be also used to specify the Perl DLL.

The name of the DLL must match the Perl version Vim was compiled with.
Currently the name is "perl512.dll".  That is for Perl 5.12.  To know for
sure edit "gvim.exe" and search for "perl\d*.dll\c".


Unix ~

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

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