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Pynvim: Python client to Neovim

Pynvim implements support for python plugins in Nvim. It also works as a library for connecting to and scripting Nvim processes through its msgpack-rpc API.

Install

Supports python 3.7 or later.

pip3 install pynvim

You can install the package without being root by adding the --user flag. Anytime you upgrade Neovim, make sure to upgrade pynvim as well:

pip3 install --upgrade pynvim

Alternatively, you can install the development version by cloning this repository and executing the following at the top level:

pip3 install .

Python Plugin API

Pynvim supports python remote plugins (via the language-agnostic Nvim rplugin interface), as well as Vim plugins (via the :python3 interface). Thus when pynvim is installed Neovim will report support for the +python3 Vim feature.

The rplugin interface allows plugins to handle vimL function calls as well as defining commands and autocommands, and such plugins can operate asynchronously without blocking nvim. For details on the new rplugin interface, see the Remote Plugin documentation.

Pynvim defines some extensions over the vim python API:

• Builtin and plugin vimL functions are available as nvim.funcs
• API functions are available as vim.api and for objects such as buffer.api
• Lua functions can be defined using vim.exec_lua and called with vim.lua
• Support for thread-safety and async requests.

See the Python Plugin API documentation for usage of this new functionality.

Known Issues

• Vim evaluates 'v:<bool>' to <class 'bool'>, whereas neovim evaluates to <class 'str'>. This is expected behaviour due to the way booleans are implemented in python as explained here.

Development

Use (and activate) a local virtualenv, for example:

python3 -m virtualenv venv
source venv/bin/activate

If you change the code, you must reinstall for the changes to take effect:

pip install .

Use pytest to run the tests. Invoking with python -m prepends the current directory to sys.path (otherwise pytest might find other versions!):

python -m pytest

For details about testing and troubleshooting, see the development documentation.

Usage from the Python REPL

A number of different transports are supported, but the simplest way to get started is with the python REPL. First, start Nvim with a known address:

$ nvim --listen /tmp/nvim.sock

Or alternatively, note the v:servername address of a running Nvim instance.

In another terminal, connect a python REPL to Nvim (note that the API is similar to the one exposed by the python-vim bridge):

>>> import pynvim
# Create a session attached to Nvim's address (`v:servername`).
>>> nvim = pynvim.attach('socket', path='/tmp/nvim.sock')
# Now do some work.
>>> buffer = nvim.current.buffer # Get the current buffer
>>> buffer[0] = 'replace first line'
>>> buffer[:] = ['replace whole buffer']
>>> nvim.command('vsplit')
>>> nvim.windows[1].width = 10
>>> nvim.vars['global_var'] = [1, 2, 3]
>>> nvim.eval('g:global_var')
[1, 2, 3]

You can embed Neovim into your python application instead of connecting to a running Neovim instance.

>>> import pynvim
>>> nvim = pynvim.attach('child', argv=["/usr/bin/env", "nvim", "--embed", "--headless"])

• The --headless argument tells nvim not to wait for a UI to connect.
• Alternatively, use --embed without --headless if your client is a UI and you want nvim to wait for your client to nvim_ui_attach before continuing startup.

See the tests for more examples.

Release

1. Create a release commit with title Pynvim x.y.z
   • list significant changes in the commit message
   • bump the version in pynvim/_version.py
2. Make a release on GitHub with the same commit/version tag and copy the message.
3. Run scripts/disable_log_statements.sh
4. Run python -m build
   • diff the release tarball dist/pynvim-x.y.z.tar.gz against the previous one.
5. Run twine upload -r pypi dist/*
   • Assumes you have a pypi account with permissions.
6. Run scripts/enable_log_statements.sh or git reset --hard to restore the working dir.
7. Bump up to the next development version in pynvim/_version.py, with prerelease suffix dev0.

License

Apache License 2.0