if_pyth.txt Nvim
NVIM REFERENCE MANUAL
The Python Interface to NVim if_pyth python Python
See provider-python for more information.
Type gO to see the table of contents.
==============================================================================
Commands python-commands
:python :py E263 E264 E887
:[range]py[thon] {stmt}
Execute Python statement {stmt}. A simple check if
the :python command is working:
:python print("Hello")
:[range]py[thon] << [trim] [{endmarker}]
{script}
{endmarker}
Execute Python script {script}. Useful for including
python code in Vim scripts. Requires Python, 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.
Example:
function! IcecreamInitialize()
python << EOF
class StrawberryIcecream:
def __call__(self):
print('EAT ME')
EOF
endfunction
To see what version of Python you have:
:python print(sys.version)
There is no need to "import sys", it's done by default.
python-environment
Environment variables set in Vim are not always available in Python. This
depends on how Vim and Python were build. Also see
https://docs.python.org/3/library/os.html#os.environ
Note: Python is very sensitive to indenting. Make sure the "class" line and
"EOF" do not have any indent.
:pydo
:[range]pydo {body} Execute Python function "def _vim_pydo(line, linenr):
{body}" for each line in the [range], with the
function arguments being set to the text of each line
in turn, without a trailing <EOL>, and the current
line number. The function should return a string or
None. If a string is returned, it becomes the text of
the line in the current turn. The default for [range]
is the whole file: "1,$".
Examples:
:pydo return "%s\t%d" % (line[::-1], len(line))
:pydo if line: return "%4d: %s" % (linenr, line)
One can use :pydo in possible conjunction with :py to filter a range using
python. For example:
:py3 << EOF
needle = vim.eval('@a')
replacement = vim.eval('@b')
def py_vim_string_replace(str):
return str.replace(needle, replacement)
EOF
:'<,'>py3do return py_vim_string_replace(line)
:pyfile :pyf
:[range]pyf[ile] {file}
Execute the Python script in {file}. The whole
argument is used as a single file name.
Both of these commands do essentially the same thing - they execute a piece of
Python code, with the "current range" python-range set to the given line
range.
In the case of :python, the code to execute is in the command-line.
In the case of :pyfile, the code to execute is the contents of the given file.
Python commands cannot be used in the sandbox.
To pass arguments you need to set sys.argv[] explicitly. Example:
:python sys.argv = ["foo", "bar"]
:pyfile myscript.py
Here are some examples python-examples
:python from vim import *
:python current.line = str.upper(current.line)
:python print("Hello")
:python str = current.buffer[42]
Note that changes (such as the "import" statements) persist from one command
to the next, just like the Python REPL.
script-here
When using a script language in-line, you might want to skip this when the
language isn't supported.
if has('python')
python << EOF
print("python works")
EOF
endif
Note that "EOF" must be at the start of the line without preceding white
space.
==============================================================================
The vim module python-vim
Python code gets all of its access to vim (with one exception - see
python-output below) via the "vim" module. The vim module implements two
methods, three constants, and one error object. You need to import the vim
module before using it:
:python import vim
Overview
:py print("Hello") # displays a message
:py vim.command(cmd) # execute an Ex command
:py w = vim.windows[n] # gets window "n"
:py cw = vim.current.window # gets the current window
:py b = vim.buffers[n] # gets buffer "n"
:py cb = vim.current.buffer # gets the current buffer
:py w.height = lines # sets the window height
:py w.cursor = (row, col) # sets the window cursor position
:py pos = w.cursor # gets a tuple (row, col)
:py name = b.name # gets the buffer file name
:py line = b[n] # gets a line from the buffer
:py lines = b[n:m] # gets a list of lines
:py num = len(b) # gets the number of lines
:py b[n] = str # sets a line in the buffer
:py b[n:m] = [str1, str2, str3] # sets a number of lines at once
:py del b[n] # deletes a line
:py del b[n:m] # deletes a number of lines
Methods of the "vim" module
vim.command(str) python-command
Executes the vim (ex-mode) command str. Returns None.
Examples:
:py vim.command("set tw=72")
:py vim.command("%s/aaa/bbb/g")
The following definition executes Normal mode commands: >python
def normal(str):
vim.command("normal "+str)
# Note the use of single quotes to delimit a string containing
# double quotes
normal('"a2dd"aP')
vim.eval(str) python-eval
Evaluates the expression str using the vim internal expression
evaluator (see expression). Returns the expression result as:
- a string if the Vim expression evaluates to a string or number
- a list if the Vim expression evaluates to a Vim list
- a dictionary if the Vim expression evaluates to a Vim dictionary
Dictionaries and lists are recursively expanded.
Examples:
:py text_width = vim.eval("&tw")
:py str = vim.eval("12+12") # NB result is a string! Use
# int() to convert to a
# number.
vim.strwidth(str) python-strwidth
Like strwidth(): returns number of display cells str occupies, tab
is counted as one cell.
vim.foreach_rtp(callable) python-foreach_rtp
Call the given callable for each path in 'runtimepath' until either
callable returns something but None, the exception is raised or there
are no longer paths. If stopped in case callable returned non-None,
vim.foreach_rtp function returns the value returned by callable.
`vim.chdir(*args, **kwargs)` python-chdir
`vim.fchdir(*args, **kwargs)` python-fchdir
Run os.chdir or os.fchdir, then all appropriate vim stuff.
Note: you should not use these functions directly, use os.chdir and
os.fchdir instead. Behavior of vim.fchdir is undefined in case
os.fchdir does not exist.
Error object of the "vim" module
vim.error python-error
Upon encountering a Vim error, Python raises an exception of type
vim.error.
Example: >python
try:
vim.command("put a")
except vim.error:
# nothing in register a
Constants of the "vim" module
Note that these are not actually constants - you could reassign them.
But this is silly, as you would then lose access to the vim objects
to which the variables referred.
vim.buffers python-buffers
A mapping object providing access to the list of vim buffers. The
object supports the following operations:
:py b = vim.buffers[i] # Indexing (read-only)
:py b in vim.buffers # Membership test
:py n = len(vim.buffers) # Number of elements
:py for b in vim.buffers: # Iterating over buffer list
vim.windows python-windows
A sequence object providing access to the list of vim windows. The
object supports the following operations:
:py w = vim.windows[i] # Indexing (read-only)
:py w in vim.windows # Membership test
:py n = len(vim.windows) # Number of elements
:py for w in vim.windows: # Sequential access
Note: vim.windows object always accesses current tab page.
python-tabpage.windows objects are bound to parent python-tabpage
object and always use windows from that tab page (or throw vim.error
in case tab page was deleted). You can keep a reference to both
without keeping a reference to vim module object or python-tabpage,
they will not lose their properties in this case.
vim.tabpages python-tabpages
A sequence object providing access to the list of vim tab pages. The
object supports the following operations:
:py t = vim.tabpages[i] # Indexing (read-only)
:py t in vim.tabpages # Membership test
:py n = len(vim.tabpages) # Number of elements
:py for t in vim.tabpages: # Sequential access
vim.current python-current
An object providing access (via specific attributes) to various
"current" objects available in vim:
vim.current.line The current line (RW) String
vim.current.buffer The current buffer (RW) Buffer
vim.current.window The current window (RW) Window
vim.current.tabpage The current tab page (RW) TabPage
vim.current.range The current line range (RO) Range
The last case deserves a little explanation. When the :python or
:pyfile command specifies a range, this range of lines becomes the
"current range". A range is a bit like a buffer, but with all access
restricted to a subset of lines. See python-range for more details.
Note: When assigning to vim.current.{buffer,window,tabpage} it expects
valid python-buffer, python-window or python-tabpage objects
respectively. Assigning triggers normal (with autocommands)
switching to given buffer, window or tab page. It is the only way to
switch UI objects in python: you can't assign to
python-tabpage.window attribute. To switch without triggering
autocommands use
py << EOF
saved_eventignore = vim.options['eventignore']
vim.options['eventignore'] = 'all'
try:
vim.current.buffer = vim.buffers[2] # Switch to buffer 2
finally:
vim.options['eventignore'] = saved_eventignore
EOF
vim.vars python-vars
vim.vvars python-vvars
Dictionary-like objects holding dictionaries with global (g:) and
vim (v:) variables respectively.
vim.options python-options
Object partly supporting mapping protocol (supports setting and
getting items) providing a read-write access to global options.
Note: unlike :set this provides access only to global options. You
cannot use this object to obtain or set local options' values or
access local-only options in any fashion. Raises KeyError if no global
option with such name exists (i.e. does not raise KeyError for
global-local options and global only options, but does for window-
and buffer-local ones). Use python-buffer objects to access to
buffer-local options and python-window objects to access to
window-local options.
Type of this object is available via "Options" attribute of vim
module.
Output from Python python-output
Vim displays all Python code output in the Vim message area. Normal
output appears as information messages, and error output appears as
error messages.
In implementation terms, this means that all output to sys.stdout
(including the output from print statements) appears as information
messages, and all output to sys.stderr (including error tracebacks)
appears as error messages.
python-input
Input (via sys.stdin, including input() and raw_input()) is not
supported, and may cause the program to crash. This should probably be
fixed.
python3-directory pythonx-directory
Python 'runtimepath' handling python-special-path
In python vim.VIM_SPECIAL_PATH special directory is used as a replacement for
the list of paths found in 'runtimepath': with this directory in sys.path and
vim.path_hooks in sys.path_hooks python will try to load module from
{rtp}/python3 and {rtp}/pythonx for each {rtp} found in 'runtimepath'.
Implementation is similar to the following, but written in C: >python
from imp import find_module, load_module
import vim
import sys
class VimModuleLoader(object):
def __init__(self, module):
self.module = module
def load_module(self, fullname, path=None):
return self.module
def _find_module(fullname, oldtail, path):
idx = oldtail.find('.')
if idx > 0:
name = oldtail[:idx]
tail = oldtail[idx+1:]
fmr = find_module(name, path)
module = load_module(fullname[:-len(oldtail)] + name, *fmr)
return _find_module(fullname, tail, module.__path__)
else:
fmr = find_module(fullname, path)
return load_module(fullname, *fmr)
# It uses vim module itself in place of VimPathFinder class: it does not
# matter for python which object has find_module function attached to as
# an attribute.
class VimPathFinder(object):
@classmethod
def find_module(cls, fullname, path=None):
try:
return VimModuleLoader(_find_module(fullname, fullname, path or vim._get_paths()))
except ImportError:
return None
@classmethod
def load_module(cls, fullname, path=None):
return _find_module(fullname, fullname, path or vim._get_paths())
def hook(path):
if path == vim.VIM_SPECIAL_PATH:
return VimPathFinder
else:
raise ImportError
sys.path_hooks.append(hook)
vim.VIM_SPECIAL_PATH python-VIM_SPECIAL_PATH
String constant used in conjunction with vim path hook. If path hook
installed by vim is requested to handle anything but path equal to
vim.VIM_SPECIAL_PATH constant it raises ImportError. In the only other
case it uses special loader.
Note: you must not use value of this constant directly, always use
vim.VIM_SPECIAL_PATH object.
vim.find_module(...) python-find_module
vim.path_hook(path) python-path_hook
Methods or objects used to implement path loading as described above.
You should not be using any of these directly except for vim.path_hook
in case you need to do something with sys.meta_path. It is not
guaranteed that any of the objects will exist in the future vim
versions.
vim._get_paths python-_get_paths
Methods returning a list of paths which will be searched for by path
hook. You should not rely on this method being present in future
versions, but can use it for debugging.
It returns a list of {rtp}/python3 and {rtp}/pythonx
directories for each {rtp} in 'runtimepath'.
==============================================================================
Buffer objects python-buffer
Buffer objects represent vim buffers. You can obtain them in a number of ways:
- via vim.current.buffer (python-current)
- from indexing vim.buffers (python-buffers)
- from the "buffer" attribute of a window (python-window)
Buffer objects have two read-only attributes - name - the full file name for
the buffer, and number - the buffer number. They also have three methods
(append, mark, and range; see below).
You can also treat buffer objects as sequence objects. In this context, they
act as if they were lists (yes, they are mutable) of strings, with each
element being a line of the buffer. All of the usual sequence operations,
including indexing, index assignment, slicing and slice assignment, work as
you would expect. Note that the result of indexing (slicing) a buffer is a
string (list of strings). This has one unusual consequence - b[:] is different
from b. In particular, "b[:] = None" deletes the whole of the buffer, whereas
"b = None" merely updates the variable b, with no effect on the buffer.
Buffer indexes start at zero, as is normal in Python. This differs from vim
line numbers, which start from 1. This is particularly relevant when dealing
with marks (see below) which use vim line numbers.
The buffer object attributes are:
b.vars Dictionary-like object used to access
buffer-variables.
b.options Mapping object (supports item getting, setting and
deleting) that provides access to buffer-local options
and buffer-local values of global-local options. Use
python-window.options if option is window-local,
this object will raise KeyError. If option is
global-local and local value is missing getting it
will return None.
b.name String, RW. Contains buffer name (full path).
Note: when assigning to b.name BufFilePre and
BufFilePost autocommands are launched.
b.number Buffer number. Can be used as python-buffers key.
Read-only.
b.valid True or False. Buffer object becomes invalid when
corresponding buffer is wiped out.
The buffer object methods are:
b.append(str) Append a line to the buffer
b.append(str, nr) Idem, below line "nr"
b.append(list) Append a list of lines to the buffer
Note that the option of supplying a list of strings to
the append method differs from the equivalent method
for Python's built-in list objects.
b.append(list, nr) Idem, below line "nr"
b.mark(name) Return a tuple (row,col) representing the position
of the named mark (can also get the []"<> marks)
b.range(s,e) Return a range object (see python-range) which
represents the part of the given buffer between line
numbers s and e inclusive.
Note that when adding a line it must not contain a line break character '\n'.
A trailing '\n' is allowed and ignored, so that you can do:
:py b.append(f.readlines())
Buffer object type is available using "Buffer" attribute of vim module.
Examples (assume b is the current buffer)
:py print(b.name) # write the buffer file name
:py b[0] = "hello!!!" # replace the top line
:py b[:] = None # delete the whole buffer
:py del b[:] # delete the whole buffer
:py b[0:0] = [ "a line" ] # add a line at the top
:py del b[2] # delete a line (the third)
:py b.append("bottom") # add a line at the bottom
:py n = len(b) # number of lines
:py (row,col) = b.mark('a') # named mark
:py r = b.range(1,5) # a sub-range of the buffer
:py b.vars["foo"] = "bar" # assign b:foo variable
:py b.options["ff"] = "dos" # set fileformat
:py del b.options["ar"] # same as :set autoread<
==============================================================================
Range objects python-range
Range objects represent a part of a vim buffer. You can obtain them in a
number of ways:
- via vim.current.range (python-current)
- from a buffer's range() method (python-buffer)
A range object is almost identical in operation to a buffer object. However,
all operations are restricted to the lines within the range (this line range
can, of course, change as a result of slice assignments, line deletions, or
the range.append() method).
The range object attributes are:
r.start Index of first line into the buffer
r.end Index of last line into the buffer
The range object methods are:
r.append(str) Append a line to the range
r.append(str, nr) Idem, after line "nr"
r.append(list) Append a list of lines to the range
Note that the option of supplying a list of strings to
the append method differs from the equivalent method
for Python's built-in list objects.
r.append(list, nr) Idem, after line "nr"
Range object type is available using "Range" attribute of vim module.
Example (assume r is the current range):
# Send all lines in a range to the default printer
vim.command("%d,%dhardcopy!" % (r.start+1,r.end+1))
==============================================================================
Window objects python-window
Window objects represent vim windows. You can obtain them in a number of ways:
- via vim.current.window (python-current)
- from indexing vim.windows (python-windows)
- from indexing "windows" attribute of a tab page (python-tabpage)
- from the "window" attribute of a tab page (python-tabpage)
You can manipulate window objects only through their attributes. They have no
methods, and no sequence or other interface.
Window attributes are:
buffer (read-only) The buffer displayed in this window
cursor (read-write) The current cursor position in the window
This is a tuple, (row,col).
height (read-write) The window height, in rows
width (read-write) The window width, in columns
vars (read-only) The window w: variables. Attribute is
unassignable, but you can change window
variables this way
options (read-only) The window-local options. Attribute is
unassignable, but you can change window
options this way. Provides access only to
window-local options, for buffer-local use
python-buffer and for global ones use
python-options. If option is global-local
and local value is missing getting it will
return None.
number (read-only) Window number. The first window has number 1.
This is zero in case it cannot be determined
(e.g. when the window object belongs to other
tab page).
row, col (read-only) On-screen window position in display cells.
First position is zero.
tabpage (read-only) Window tab page.
valid (read-write) True or False. Window object becomes invalid
when corresponding window is closed.
The height attribute is writable only if the screen is split horizontally.
The width attribute is writable only if the screen is split vertically.
Window object type is available using "Window" attribute of vim module.
==============================================================================
Tab page objects python-tabpage
Tab page objects represent vim tab pages. You can obtain them in a number of
ways:
- via vim.current.tabpage (python-current)
- from indexing vim.tabpages (python-tabpages)
You can use this object to access tab page windows. They have no methods and
no sequence or other interfaces.
Tab page attributes are:
number The tab page number like the one returned by
tabpagenr().
windows Like python-windows, but for current tab page.
vars The tab page t: variables.
window Current tabpage window.
valid True or False. Tab page object becomes invalid when
corresponding tab page is closed.
TabPage object type is available using "TabPage" attribute of vim module.
==============================================================================
pyeval() and py3eval() Vim functions python-pyeval
To facilitate bi-directional interface, you can use pyeval() and py3eval()
functions to evaluate Python expressions and pass their values to Vim script.
pyxeval() is also available.
==============================================================================
Python 3 python3
As Python 3 is the only supported version in Nvim, "python" is synonymous
with "python3" in the current version. However, code that aims to support older
versions of Nvim, as well as Vim, should prefer to use "python3" variants
explicitly if Python 3 is required.
:py3 :python3
:[range]py3 {stmt}
:[range]py3 << [trim] [{endmarker}]
{script}
{endmarker}
:[range]python3 {stmt}
:[range]python3 << [trim] [{endmarker}]
{script}
{endmarker}
The :py3 and :python3 commands work similar to :python. A
simple check if the :py3 command is working:
:py3 print("Hello")
To see what version of Python you have:
:py3 import sys
:py3 print(sys.version)
:py3file
:[range]py3f[ile] {file}
The :py3file command works similar to :pyfile.
:py3do
:[range]py3do {body}
The :py3do command works similar to :pydo.
E880
Raising SystemExit exception in python isn't endorsed way to quit vim, use:
:py vim.command("qall!")
has-python
You can test if Python is available with:
if has('pythonx')
echo 'there is Python'
endif
if has('python3')
echo 'there is Python 3.x'
endif
Python 2 is no longer supported. Thus has('python') always returns
zero for backwards compatibility reasons.
==============================================================================
Python X python_x pythonx
The "pythonx" and "pyx" prefixes were introduced for python code which
works with Python 2.6+ and Python 3. As Nvim only supports Python 3,
all these commands are now synonymous to their "python3" equivalents.
:pyx :pythonx
:pyx and :pythonx work the same as :python3. To check if :pyx works:
:pyx print("Hello")
To see what version of Python is being used:
:pyx import sys
:pyx print(sys.version)
:pyxfile
:pyxfile works the same as :py3file.
:pyxdo
:pyxdo works the same as :py3do.
has-pythonx
To check if pyx* functions and commands are available:
if has('pythonx')
echo 'pyx* commands are available. (Python ' .. &pyx .. ')'
endif
==============================================================================
vim:tw=78:ts=8:noet:ft=help:norl: