Mercurial > vim
view runtime/doc/usr_08.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
*usr_08.txt* For Vim version 9.0. Last change: 2021 May 20 VIM USER MANUAL - by Bram Moolenaar Splitting windows Display two different files above each other. Or view two locations in the file at the same time. See the difference between two files by putting them side by side. All this is possible with split windows. |08.1| Split a window |08.2| Split a window on another file |08.3| Window size |08.4| Vertical splits |08.5| Moving windows |08.6| Commands for all windows |08.7| Viewing differences with vimdiff |08.8| Various |08.9| Tab pages Next chapter: |usr_09.txt| Using the GUI Previous chapter: |usr_07.txt| Editing more than one file Table of contents: |usr_toc.txt| ============================================================================== *08.1* Split a window The easiest way to open a new window is to use the following command: > :split This command splits the screen into two windows and leaves the cursor in the top one: +----------------------------------+ |/* file one.c */ | |~ | |~ | |one.c=============================| |/* file one.c */ | |~ | |one.c=============================| | | +----------------------------------+ What you see here is two windows on the same file. The line with "====" is the status line. It displays information about the window above it. (In practice the status line will be in reverse video.) The two windows allow you to view two parts of the same file. For example, you could make the top window show the variable declarations of a program, and the bottom one the code that uses these variables. The CTRL-W w command can be used to jump between the windows. If you are in the top window, CTRL-W w jumps to the window below it. If you are in the bottom window it will jump to the first window. (CTRL-W CTRL-W does the same thing, in case you let go of the CTRL key a bit later.) CLOSE THE WINDOW To close a window, use the command: > :close Actually, any command that quits editing a file works, like ":quit" and "ZZ". But ":close" prevents you from accidentally exiting Vim when you close the last window. CLOSING ALL OTHER WINDOWS If you have opened a whole bunch of windows, but now want to concentrate on one of them, this command will be useful: > :only This closes all windows, except for the current one. If any of the other windows has changes, you will get an error message and that window won't be closed. ============================================================================== *08.2* Split a window on another file The following command opens a second window and starts editing the given file: > :split two.c If you were editing one.c, then the result looks like this: +----------------------------------+ |/* file two.c */ | |~ | |~ | |two.c=============================| |/* file one.c */ | |~ | |one.c=============================| | | +----------------------------------+ To open a window on a new, empty file, use this: > :new You can repeat the ":split" and ":new" commands to create as many windows as you like. ============================================================================== *08.3* Window size The ":split" command can take a number argument. If specified, this will be the height of the new window. For example, the following opens a new window three lines high and starts editing the file alpha.c: > :3split alpha.c For existing windows you can change the size in several ways. When you have a working mouse, it is easy: Move the mouse pointer to the status line that separates two windows, and drag it up or down. To increase the size of a window: > CTRL-W + To decrease it: > CTRL-W - Both of these commands take a count and increase or decrease the window size by that many lines. Thus "4 CTRL-W +" make the window four lines higher. To set the window height to a specified number of lines: > {height}CTRL-W _ That's: a number {height}, CTRL-W and then an underscore (the - key with Shift on English-US keyboards). To make a window as high as it can be, use the CTRL-W _ command without a count. USING THE MOUSE In Vim you can do many things very quickly from the keyboard. Unfortunately, the window resizing commands require quite a bit of typing. In this case, using the mouse is faster. Position the mouse pointer on a status line. Now press the left mouse button and drag. The status line will move, thus making the window on one side higher and the other smaller. OPTIONS The 'winheight' option can be set to a minimal desired height of a window and 'winminheight' to a hard minimum height. Likewise, there is 'winwidth' for the minimal desired width and 'winminwidth' for the hard minimum width. The 'equalalways' option, when set, makes Vim equalize the windows sizes when a window is closed or opened. ============================================================================== *08.4* Vertical splits The ":split" command creates the new window above the current one. To make the window appear at the left side, use: > :vsplit or: > :vsplit two.c The result looks something like this: +--------------------------------------+ |/* file two.c */ |/* file one.c */ | |~ |~ | |~ |~ | |~ |~ | |two.c===============one.c=============| | | +--------------------------------------+ Actually, the | lines in the middle will be in reverse video. This is called the vertical separator. It separates the two windows left and right of it. There is also the ":vnew" command, to open a vertically split window on a new, empty file. Another way to do this: > :vertical new The ":vertical" command can be inserted before another command that splits a window. This will cause that command to split the window vertically instead of horizontally. (If the command doesn't split a window, it works unmodified.) MOVING BETWEEN WINDOWS Since you can split windows horizontally and vertically as much as you like, you can create almost any layout of windows. Then you can use these commands to move between them: CTRL-W h move to the window on the left CTRL-W j move to the window below CTRL-W k move to the window above CTRL-W l move to the window on the right CTRL-W t move to the TOP window CTRL-W b move to the BOTTOM window You will notice the same letters as used for moving the cursor. And the cursor keys can also be used, if you like. More commands to move to other windows: |Q_wi|. ============================================================================== *08.5* Moving windows You have split a few windows, but now they are in the wrong place. Then you need a command to move the window somewhere else. For example, you have three windows like this: +----------------------------------+ |/* file two.c */ | |~ | |~ | |two.c=============================| |/* file three.c */ | |~ | |~ | |three.c===========================| |/* file one.c */ | |~ | |one.c=============================| | | +----------------------------------+ Clearly the last one should be at the top. Go to that window (using CTRL-W w) and then type this command: > CTRL-W K This uses the uppercase letter K. What happens is that the window is moved to the very top. You will notice that K is again used for moving upwards. When you have vertical splits, CTRL-W K will move the current window to the top and make it occupy the full width of the Vim window. If this is your layout: +-------------------------------------------+ |/* two.c */ |/* three.c */ |/* one.c */ | |~ |~ |~ | |~ |~ |~ | |~ |~ |~ | |~ |~ |~ | |~ |~ |~ | |two.c=========three.c=========one.c========| | | +-------------------------------------------+ Then using CTRL-W K in the middle window (three.c) will result in: +-------------------------------------------+ |/* three.c */ | |~ | |~ | |three.c====================================| |/* two.c */ |/* one.c */ | |~ |~ | |two.c==================one.c===============| | | +-------------------------------------------+ The other three similar commands (you can probably guess these now): CTRL-W H move window to the far left CTRL-W J move window to the bottom CTRL-W L move window to the far right ============================================================================== *08.6* Commands for all windows When you have several windows open and you want to quit Vim, you can close each window separately. A quicker way is using this command: > :qall This stands for "quit all". If any of the windows contain changes, Vim will not exit. The cursor will automatically be positioned in a window with changes. You can then either use ":write" to save the changes, or ":quit!" to throw them away. If you know there are windows with changes, and you want to save all these changes, use this command: > :wall This stands for "write all". But actually, it only writes files with changes. Vim knows it doesn't make sense to write files that were not changed. And then there is the combination of ":qall" and ":wall": the "write and quit all" command: > :wqall This writes all modified files and quits Vim. Finally, there is a command that quits Vim and throws away all changes: > :qall! Be careful, there is no way to undo this command! OPENING A WINDOW FOR ALL ARGUMENTS To make Vim open a window for each file, start it with the "-o" argument: > vim -o one.txt two.txt three.txt This results in: +-------------------------------+ |file one.txt | |~ | |one.txt========================| |file two.txt | |~ | |two.txt========================| |file three.txt | |~ | |three.txt======================| | | +-------------------------------+ The "-O" argument is used to get vertically split windows. When Vim is already running, the ":all" command opens a window for each file in the argument list. ":vertical all" does it with vertical splits. ============================================================================== *08.7* Viewing differences with vimdiff There is a special way to start Vim, which shows the differences between two files. Let's take a file "main.c" and insert a few characters in one line. Write this file with the 'backup' option set, so that the backup file "main.c~" will contain the previous version of the file. Type this command in a shell (not in Vim): > vimdiff main.c~ main.c Vim will start, with two windows side by side. You will only see the line in which you added characters, and a few lines above and below it. VV VV +-----------------------------------------+ |+ +--123 lines: /* a|+ +--123 lines: /* a| <- fold | text | text | | text | text | | text | text | | text | changed text | <- changed line | text | text | | text | ------------------| <- deleted line | text | text | | text | text | | text | text | |+ +--432 lines: text|+ +--432 lines: text| <- fold | ~ | ~ | | ~ | ~ | |main.c~==============main.c==============| | | +-----------------------------------------+ (This picture doesn't show the highlighting, use the vimdiff command for a better look.) The lines that were not modified have been collapsed into one line. This is called a closed fold. They are indicated in the picture with "<- fold". Thus the single fold line at the top stands for 123 text lines. These lines are equal in both files. The line marked with "<- changed line" is highlighted, and the inserted text is displayed with another color. This clearly shows what the difference is between the two files. The line that was deleted is displayed with "---" in the main.c window. See the "<- deleted line" marker in the picture. These characters are not really there. They just fill up main.c, so that it displays the same number of lines as the other window. THE FOLD COLUMN Each window has a column on the left with a slightly different background. In the picture above these are indicated with "VV". You notice there is a plus character there, in front of each closed fold. Move the mouse pointer to that plus and click the left button. The fold will open, and you can see the text that it contains. The fold column contains a minus sign for an open fold. If you click on this -, the fold will close. Obviously, this only works when you have a working mouse. You can also use "zo" to open a fold and "zc" to close it. DIFFING IN VIM Another way to start in diff mode can be done from inside Vim. Edit the "main.c" file, then make a split and show the differences: > :edit main.c :vertical diffsplit main.c~ The ":vertical" command is used to make the window split vertically. If you omit this, you will get a horizontal split. If you have a patch or diff file, you can use the third way to start diff mode. First edit the file to which the patch applies. Then tell Vim the name of the patch file: > :edit main.c :vertical diffpatch main.c.diff WARNING: The patch file must contain only one patch, for the file you are editing. Otherwise you will get a lot of error messages, and some files might be patched unexpectedly. The patching will only be done to the copy of the file in Vim. The file on your harddisk will remain unmodified (until you decide to write the file). SCROLL BINDING When the files have more changes, you can scroll in the usual way. Vim will try to keep both the windows start at the same position, so you can easily see the differences side by side. When you don't want this for a moment, use this command: > :set noscrollbind JUMPING TO CHANGES When you have disabled folding in some way, it may be difficult to find the changes. Use this command to jump forward to the next change: > ]c To go the other way use: > [c Prepended a count to jump further away. REMOVING CHANGES You can move text from one window to the other. This either removes differences or adds new ones. Vim doesn't keep the highlighting updated in all situations. To update it use this command: > :diffupdate To remove a difference, you can move the text in a highlighted block from one window to another. Take the "main.c" and "main.c~" example above. Move the cursor to the left window, on the line that was deleted in the other window. Now type this command: > dp The change will be removed by putting the text of the current window in the other window. "dp" stands for "diff put". You can also do it the other way around. Move the cursor to the right window, to the line where "changed" was inserted. Now type this command: > do The change will now be removed by getting the text from the other window. Since there are no changes left now, Vim puts all text in a closed fold. "do" stands for "diff obtain". "dg" would have been better, but that already has a different meaning ("dgg" deletes from the cursor until the first line). For details about diff mode, see |vimdiff|. ============================================================================== *08.8* Various The 'laststatus' option can be used to specify when the last window has a statusline: 0 never 1 only when there are split windows (the default) 2 always Many commands that edit another file have a variant that splits the window. For Command-line commands this is done by prepending an "s". For example: ":tag" jumps to a tag, ":stag" splits the window and jumps to a tag. For Normal mode commands a CTRL-W is prepended. CTRL-^ jumps to the alternate file, CTRL-W CTRL-^ splits the window and edits the alternate file. The 'splitbelow' option can be set to make a new window appear below the current window. The 'splitright' option can be set to make a vertically split window appear right of the current window. When splitting a window you can prepend a modifier command to tell where the window is to appear: :leftabove {cmd} left or above the current window :aboveleft {cmd} idem :rightbelow {cmd} right or below the current window :belowright {cmd} idem :topleft {cmd} at the top or left of the Vim window :botright {cmd} at the bottom or right of the Vim window ============================================================================== *08.9* Tab pages You will have noticed that windows never overlap. That means you quickly run out of screen space. The solution for this is called Tab pages. Assume you are editing "thisfile". To create a new tab page use this command: > :tabedit thatfile This will edit the file "thatfile" in a window that occupies the whole Vim window. And you will notice a bar at the top with the two file names: +----------------------------------+ | thisfile | /thatfile/ __________X| (thatfile is bold) |/* thatfile */ | |that | |that | |~ | |~ | |~ | | | +----------------------------------+ You now have two tab pages. The first one has a window for "thisfile" and the second one a window for "thatfile". It's like two pages that are on top of each other, with a tab sticking out of each page showing the file name. Now use the mouse to click on "thisfile" in the top line. The result is +----------------------------------+ | /thisfile/ | thatfile __________X| (thisfile is bold) |/* thisfile */ | |this | |this | |~ | |~ | |~ | | | +----------------------------------+ Thus you can switch between tab pages by clicking on the label in the top line. If you don't have a mouse or don't want to use it, you can use the "gt" command. Mnemonic: Goto Tab. Now let's create another tab page with the command: > :tab split This makes a new tab page with one window that is editing the same buffer as the window we were in: +-------------------------------------+ | thisfile | /thisfile/ | thatfile __X| (thisfile is bold) |/* thisfile */ | |this | |this | |~ | |~ | |~ | | | +-------------------------------------+ You can put ":tab" before any Ex command that opens a window. The window will be opened in a new tab page. Another example: > :tab help gt Will show the help text for "gt" in a new tab page. A few more things you can do with tab pages: - click with the mouse in the space after the last label The next tab page will be selected, like with "gt". - click with the mouse on the "X" in the top right corner The current tab page will be closed. Unless there are unsaved changes in the current tab page. - double click with the mouse in the top line A new tab page will be created. - the "tabonly" command Closes all tab pages except the current one. Unless there are unsaved changes in other tab pages. For more information about tab pages see |tab-page|. ============================================================================== Next chapter: |usr_09.txt| Using the GUI Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: