Mercurial > vim
view runtime/doc/usr_04.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_04.txt* For Vim version 9.0. Last change: 2021 Feb 22 VIM USER MANUAL - by Bram Moolenaar Making small changes This chapter shows you several ways of making corrections and moving text around. It teaches you the three basic ways to change text: operator-motion, Visual mode and text objects. |04.1| Operators and motions |04.2| Changing text |04.3| Repeating a change |04.4| Visual mode |04.5| Moving text |04.6| Copying text |04.7| Using the clipboard |04.8| Text objects |04.9| Replace mode |04.10| Conclusion Next chapter: |usr_05.txt| Set your settings Previous chapter: |usr_03.txt| Moving around Table of contents: |usr_toc.txt| ============================================================================== *04.1* Operators and motions In chapter 2 you learned the "x" command to delete a single character. And using a count: "4x" deletes four characters. The "dw" command deletes a word. You may recognize the "w" command as the move word command. In fact, the "d" command may be followed by any motion command, and it deletes from the current location to the place where the cursor winds up. The "4w" command, for example, moves the cursor over four words. The "d4w" command deletes four words. To err is human. To really foul up you need a computer. ~ ------------------> d4w To err is human. you need a computer. ~ Vim only deletes up to the position where the motion takes the cursor. That's because Vim knows that you probably don't want to delete the first character of a word. If you use the "e" command to move to the end of a word, Vim guesses that you do want to include that last character: To err is human. you need a computer. ~ --------> d2e To err is human. a computer. ~ Whether the character under the cursor is included depends on the command you used to move to that character. The reference manual calls this "exclusive" when the character isn't included and "inclusive" when it is. The "$" command moves to the end of a line. The "d$" command deletes from the cursor to the end of the line. This is an inclusive motion, thus the last character of the line is included in the delete operation: To err is human. a computer. ~ ------------> d$ To err is human ~ There is a pattern here: operator-motion. You first type an operator command. For example, "d" is the delete operator. Then you type a motion command like "4l" or "w". This way you can operate on any text you can move over. ============================================================================== *04.2* Changing text Another operator is "c", change. It acts just like the "d" operator, except it leaves you in Insert mode. For example, "cw" changes a word. Or more specifically, it deletes a word and then puts you in Insert mode. To err is human ~ -------> c2wbe<Esc> To be human ~ This "c2wbe<Esc>" contains these bits: c the change operator 2w move two words (they are deleted and Insert mode started) be insert this text <Esc> back to Normal mode You will have noticed something strange: The space before "human" isn't deleted. There is a saying that for every problem there is an answer that is simple, clear, and wrong. That is the case with the example used here for the "cw" command. The c operator works just like the d operator, with one exception: "cw". It actually works like "ce", change to end of word. Thus the space after the word isn't included. This is an exception that dates back to the old Vi. Since many people are used to it now, the inconsistency has remained in Vim. MORE CHANGES Like "dd" deletes a whole line, "cc" changes a whole line. It keeps the existing indent (leading white space) though. Just like "d$" deletes until the end of the line, "c$" changes until the end of the line. It's like doing "d$" to delete the text and then "a" to start Insert mode and append new text. SHORTCUTS Some operator-motion commands are used so often that they have been given a single-letter command: x stands for dl (delete character under the cursor) X stands for dh (delete character left of the cursor) D stands for d$ (delete to end of the line) C stands for c$ (change to end of the line) s stands for cl (change one character) S stands for cc (change a whole line) WHERE TO PUT THE COUNT The commands "3dw" and "d3w" delete three words. If you want to get really picky about things, the first command, "3dw", deletes one word three times; the command "d3w" deletes three words once. This is a difference without a distinction. You can actually put in two counts, however. For example, "3d2w" deletes two words, repeated three times, for a total of six words. REPLACING WITH ONE CHARACTER The "r" command is not an operator. It waits for you to type a character, and will replace the character under the cursor with it. You could do the same with "cl" or with the "s" command, but with "r" you don't have to press <Esc> to get back out of insert mode. there is somerhing grong here ~ rT rt rw There is something wrong here ~ Using a count with "r" causes that many characters to be replaced with the same character. Example: There is something wrong here ~ 5rx There is something xxxxx here ~ To replace a character with a line break use "r<Enter>". This deletes one character and inserts a line break. Using a count here only applies to the number of characters deleted: "4r<Enter>" replaces four characters with one line break. ============================================================================== *04.3* Repeating a change The "." command is one of the simplest yet powerful commands in Vim. It repeats the last change. For instance, suppose you are editing an HTML file and want to delete all the <B> tags. You position the cursor on the first < and delete the <B> with the command "df>". You then go to the < of the next </B> and delete it using the "." command. The "." command executes the last change command (in this case, "df>"). To delete another tag, position the cursor on the < and use the "." command. To <B>generate</B> a table of <B>contents ~ f< find first < ---> df> delete to > --> f< find next < ---------> . repeat df> ---> f< find next < -------------> . repeat df> --> The "." command works for all changes you make, except for "u" (undo), CTRL-R (redo) and commands that start with a colon (:). Another example: You want to change the word "four" to "five". It appears several times in your text. You can do this quickly with this sequence of commands: /four<Enter> find the first string "four" cwfive<Esc> change the word to "five" n find the next "four" . repeat the change to "five" n find the next "four" . repeat the change etc. ============================================================================== *04.4* Visual mode To delete simple items the operator-motion changes work quite well. But often it's not so easy to decide which command will move over the text you want to change. Then you can use Visual mode. You start Visual mode by pressing "v". You move the cursor over the text you want to work on. While you do this, the text is highlighted. Finally type the operator command. For example, to delete from the middle of one word to the middle of another word: This is an examination sample of visual mode ~ ----------> velllld This is an example of visual mode ~ When doing this you don't really have to count how many times you have to press "l" to end up in the right position. You can immediately see what text will be deleted when you press "d". If at any time you decide you don't want to do anything with the highlighted text, just press <Esc> and Visual mode will stop without doing anything. SELECTING LINES If you want to work on whole lines, use "V" to start Visual mode. You will see right away that the whole line is highlighted, without moving around. When you move left or right nothing changes. When you move up or down the selection is extended whole lines at a time. For example, select three lines with "Vjj": +------------------------+ | text more text | >> | more text more text | | selected lines >> | text text text | | Vjj >> | text more | V | more text more | +------------------------+ SELECTING BLOCKS If you want to work on a rectangular block of characters, use CTRL-V to start Visual mode. This is very useful when working on tables. name Q1 Q2 Q3 pierre 123 455 234 john 0 90 39 steve 392 63 334 To delete the middle "Q2" column, move the cursor to the "Q" of "Q2". Press CTRL-V to start blockwise Visual mode. Now move the cursor three lines down with "3j" and to the next word with "w". You can see the first character of the last column is included. To exclude it, use "h". Now press "d" and the middle column is gone. GOING TO THE OTHER SIDE If you have selected some text in Visual mode, and discover that you need to change the other end of the selection, use the "o" command (Hint: o for other end). The cursor will go to the other end, and you can move the cursor to change where the selection starts. Pressing "o" again brings you back to the other end. When using blockwise selection, you have four corners. "o" only takes you to one of the other corners, diagonally. Use "O" to move to the other corner in the same line. Note that "o" and "O" in Visual mode work very differently from Normal mode, where they open a new line below or above the cursor. ============================================================================== *04.5* Moving text When you delete something with "d", "x", or another command, the text is saved. You can paste it back by using the "p" command. (The Vim name for this is put). Take a look at how this works. First you will delete an entire line, by putting the cursor on the line you want to delete and typing "dd". Now you move the cursor to where you want to put the line and use the "p" (put) command. The line is inserted on the line below the cursor. a line a line a line line 2 dd line 3 p line 3 line 3 line 2 Because you deleted an entire line, the "p" command placed the text line below the cursor. If you delete part of a line (a word, for instance), the "p" command puts it just after the cursor. Some more boring try text to out commands. ~ ----> dw Some more boring text to out commands. ~ -------> welp Some more boring text to try out commands. ~ MORE ON PUTTING The "P" command puts text like "p", but before the cursor. When you deleted a whole line with "dd", "P" will put it back above the cursor. When you deleted a word with "dw", "P" will put it back just before the cursor. You can repeat putting as many times as you like. The same text will be used. You can use a count with "p" and "P". The text will be repeated as many times as specified with the count. Thus "dd" and then "3p" puts three copies of the same deleted line. SWAPPING TWO CHARACTERS Frequently when you are typing, your fingers get ahead of your brain (or the other way around?). The result is a typo such as "teh" for "the". Vim makes it easy to correct such problems. Just put the cursor on the e of "teh" and execute the command "xp". This works as follows: "x" deletes the character e and places it in a register. "p" puts the text after the cursor, which is after the h. teh th the ~ x p ============================================================================== *04.6* Copying text To copy text from one place to another, you could delete it, use "u" to undo the deletion and then "p" to put it somewhere else. There is an easier way: yanking. The "y" operator copies text into a register. Then a "p" command can be used to put it. Yanking is just a Vim name for copying. The "c" letter was already used for the change operator, and "y" was still available. Calling this operator "yank" made it easier to remember to use the "y" key. Since "y" is an operator, you use "yw" to yank a word. A count is possible as usual. To yank two words use "y2w". Example: let sqr = LongVariable * ~ --------------> y2w let sqr = LongVariable * ~ p let sqr = LongVariable * LongVariable ~ Notice that "yw" includes the white space after a word. If you don't want this, use "ye". The "yy" command yanks a whole line, just like "dd" deletes a whole line. Unexpectedly, while "D" deletes from the cursor to the end of the line, "Y" works like "yy", it yanks the whole line. Watch out for this inconsistency! Use "y$" to yank to the end of the line. a text line yy a text line a text line line 2 line 2 p line 2 last line last line a text line last line ============================================================================== *04.7* Using the clipboard If you are using the GUI version of Vim (gvim), you can find the "Copy" item in the "Edit" menu. First select some text with Visual mode, then use the Edit/Copy menu item. The selected text is now copied to the clipboard. You can paste the text in other programs. In Vim itself too. If you have copied text to the clipboard in another application, you can paste it in Vim with the Edit/Paste menu item. This works in Normal mode and Insert mode. In Visual mode the selected text is replaced with the pasted text. The "Cut" menu item deletes the text before it's put on the clipboard. The "Copy", "Cut" and "Paste" items are also available in the popup menu (only when there is a popup menu, of course). If your Vim has a toolbar, you can also find these items there. If you are not using the GUI, or if you don't like using a menu, you have to use another way. You use the normal "y" (yank) and "p" (put) commands, but prepend "* (double-quote star) before it. To copy a line to the clipboard: > "*yy To put text from the clipboard back into the text: > "*p This only works on versions of Vim that include clipboard support. More about the clipboard can be found in section |09.3| and here: |clipboard|. ============================================================================== *04.8* Text objects If the cursor is in the middle of a word and you want to delete that word, you need to move back to its start before you can do "dw". There is a simpler way to do this: "daw". this is some example text. ~ daw this is some text. ~ The "d" of "daw" is the delete operator. "aw" is a text object. Hint: "aw" stands for "A Word". Thus "daw" is "Delete A Word". To be precise, the white space after the word is also deleted (or the white space before the word if at the end of the line). Using text objects is the third way to make changes in Vim. We already had operator-motion and Visual mode. Now we add operator-text object. It is very similar to operator-motion, but instead of operating on the text between the cursor position before and after a movement command, the text object is used as a whole. It doesn't matter where in the object the cursor was. To change a whole sentence use "cis". Take this text: Hello there. This ~ is an example. Just ~ some text. ~ Move to the start of the second line, on "is an". Now use "cis": Hello there. Just ~ some text. ~ The cursor is in between the blanks in the first line. Now you type the new sentence "Another line.": Hello there. Another line. Just ~ some text. ~ "cis" consists of the "c" (change) operator and the "is" text object. This stands for "Inner Sentence". There is also the "as" ("A Sentence") object. The difference is that "as" includes the white space after the sentence and "is" doesn't. If you would delete a sentence, you want to delete the white space at the same time, thus use "das". If you want to type new text the white space can remain, thus you use "cis". You can also use text objects in Visual mode. It will include the text object in the Visual selection. Visual mode continues, thus you can do this several times. For example, start Visual mode with "v" and select a sentence with "as". Now you can repeat "as" to include more sentences. Finally you use an operator to do something with the selected sentences. You can find a long list of text objects here: |text-objects|. ============================================================================== *04.9* Replace mode The "R" command causes Vim to enter replace mode. In this mode, each character you type replaces the one under the cursor. This continues until you type <Esc>. In this example you start Replace mode on the first "t" of "text": This is text. ~ Rinteresting.<Esc> This is interesting. ~ You may have noticed that this command replaced 5 characters in the line with twelve others. The "R" command automatically extends the line if it runs out of characters to replace. It will not continue on the next line. You can switch between Insert mode and Replace mode with the <Insert> key. When you use <BS> (backspace) to make a correction, you will notice that the old text is put back. Thus it works like an undo command for the previously typed character. ============================================================================== *04.10* Conclusion The operators, movement commands and text objects give you the possibility to make lots of combinations. Now that you know how they work, you can use N operators with M movement commands to make N * M commands! You can find a list of operators here: |operator|. For example, there are many other ways to delete pieces of text. Here are a few common ones: x delete character under the cursor (short for "dl") X delete character before the cursor (short for "dh") D delete from cursor to end of line (short for "d$") dw delete from cursor to next start of word db delete from cursor to previous start of word diw delete word under the cursor (excluding white space) daw delete word under the cursor (including white space) dG delete until the end of the file dgg delete until the start of the file If you use "c" instead of "d" they become change commands. And with "y" you yank the text. And so forth. There are a few common commands to make changes that didn't fit somewhere else: ~ Change case of the character under the cursor, and move the cursor to the next character. This is not an operator (unless 'tildeop' is set), thus you can't use it with a motion command. It does work in Visual mode, where it changes case for all the selected text. I Start Insert mode after moving the cursor to the first non-blank in the line. A Start Insert mode after moving the cursor to the end of the line. ============================================================================== Next chapter: |usr_05.txt| Set your settings Copyright: see |manual-copyright| vim:tw=78:ts=8:noet:ft=help:norl: