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Enriching python coding in Vim

Enriching python coding in Vim


Enriching python coding.

1. Installation

Using vim-plug

Plug 'relastle/vim-nayvy'

2. Usage

2.1 Commands





NayvyTestGenerate & NayvyTestGenerateFZF


2.2 Use with other plugin.

2.2.1 ALE

ALE, Asynchronous Lint Engine, is one of the SOTA plugins of Vim.
Even though LSP is becoming more and more popular, the plugin provides brilliant features,
including great abstraction against code fixer.

Thus, vim-nayvy provides code fixer funciton nayvy#ale_fixer.

Vim script Below is a example of using nayvy#ale_fixer with
autopep8 and isort.

let g:ale_fixers = {
      \ 'python': ['nayvy#ale_fixer', 'autopep8', 'isort'],
      \ }

" or if you already defined `g:ale_fixer`, write
let g:ale_fixers['python'] = ['nayvy#ale_fixer', 'autopep8', 'isort']

And here is demonstrations.


2.2.2 ultisnips

vim-nayvy provides auto_import function used with UltiSnips' snippet.
UltiSnips provides post_expand trigger for each single snippet,
which executes prerefined command when the snippet is expanded.

The snippet fragment below import auto_import function from nayvy,
and defines pretty print post fix completion that add import statement
from pprint import pprint as pp if not exists.

global !p
from nayvy_vim_if.ultisnips import (

post_expand "auto_import(snip, 'from pprint import pprint as pp', 0)"
snippet '((\S|\.)+)\.pp' "pprint postfix completion" r
var_name = match.group(1)
snip.rv = "pp(" + var_name + ")"

(The sample snippet is here and tested with a vader script)

Note that three arguments of auto_import are

  • Snip object of UltiSnips. you should always pass snip
  • Import statement string
  • The import level
    • 0: Standard library imports.
    • 1: Related third party imports.
    • 2: Local application/library specific imports.

(cf. https://www.python.org/dev/peps/pep-0008/#imports)

And here is demonstrations.


2.2.3 coc.nvim

This plugins also provide auto-completion of importable items, follewd by auto-importing of the completed items.
This is thanks to coc's ability to easily creating new coc sources
Create custom source · neoclide/coc.nvim Wiki.

You can see how auto-importing is conducted in the GIF below.


When you auto-complete Class/Function inside the current python project, the signature and docstring will also be shown like this.


To use this function, please bundle neoclide/coc.nvim as well as relastle/vim-nayvy.

Plug 'neoclide/coc.nvim', {'branch': 'release'}
Plug 'relastle/vim-nayvy'

The automatic import in completion is conducted by the item-selected event.
By default, the event is fired by Ctrl + y (when the item is focused in pmenu).

If you use the following settings described here,

" Use <cr> to confirm completion, `<C-g>u` means break undo chain at current
" position. Coc only does snippet and additional edit on confirm.
" <cr> could be remapped by other vim plugin, try `:verbose imap <CR>`.
if exists('*complete_info')
  inoremap <expr> <cr> complete_info()["selected"] != "-1" ? "\<C-y>" : "\<C-g>u\<CR>"
  inoremap <expr> <cr> pumvisible() ? "\<C-y>" : "\<C-g>u\<CR>"

the completion event can be trigger by just Enter (, which I personally recommend 👍).

3. Configurations

3.1 Configuration with vim g: variable or environment variable.

All configurable settings can be configured through vim script variables and environment variables.

This is because you may set some project-specific settings different from your global vim settings.
Thus, the priority of load settings is as follows.

Environment variable -> Vim script variable -> Default variable
Vim Script variable name Environment variable name Description
g:nayvy_import_path_format $NAYVY_IMPORT_PATH_FORMAT Define the import statement format when importing the class/function inside the same package.
g:nayvy_linter_for_fix $NAYVY_LINTER_FOR_FIX Define the linter to use when autofixing the missing imports or unused imports.
g:nayvy_pyproject_root_markers $NAYVY_PYPROJECT_ROOT_MARKERS Define marker (filenames) indicating the python project root directory.
g:nayvy_import_config_path $NAYVY_IMPORT_CONFIG_PATH Define the file path containing your own import statement lines.
g:nayvy_coc_enabled $NAYVY_COC_ENABLED Define whether coc is enabled (1) or not (0).
g:nayvy_coc_completion_icon $NAYVY_COC_COMPLETION_ICON Define icon rendered in the completion item fron nayvy coc sources.
g:nayvy_coc_menu_max_width $NAYVY_COC_MENU_MAX_WIDTH Define max length of menu represented in completion menu by the coc source.

g:nayvy_import_path_format ($NAYVY_IMPORT_PATH_FORMAT)

  • all_absolute (Prefer all project classes/functions are imported with absolute path.)
  • all_relative (Prefer all project classes/functions are imported with relative path.)
  • under_relative (Prefer sub-package classes/functions are imported with relative path and ther other with absolute path)

default: all_absolute

g:nayvy_linter_for_fix ($NAYVY_LINTER_FOR_FIX)

  • pyflakes
  • flake8

default: pyflakes

g:nayvy_pyproject_root_markers ($NAYVY_PYPROJECT_ROOT_MARKERS)

Example of vim

let g:nayvy_pyproject_root_markers = [
  \ 'pyproject.toml',
  \ 'setup.py',
  \ 'setup.cfg',
  \ 'requirements.txt',
\ ]

Example of environment variable

export NAYVY_PYPROJECT_ROOT_MARKERS='pyproject.toml,setup.py'  # comma-separated format

default: ['pyproject.toml', 'setup.py', 'setup.cfg', 'requirements.txt']

g:nayvy_import_config_path ($NAYVY_IMPORT_CONFIG_PATH)

see the section below (3.2 Import configration).

default: ``

g:nayvy_coc_enabled ($NAYVY_COC_ENABLED)

  • 1: enabled
  • 0: disabled

default: 1

g:nayvy_coc_completion_icon ($NAYVY_COC_COMPLETION_ICON)


Please set any string as you like 😄.

default:  nayvy

g:nayvy_coc_menu_max_width ($NAYVY_COC_MENU_MAX_WIDTH)

If the completion menu gets too wide, it may bother you.
So you can specify the max length of whole import statement.
If the statement length gets longer than the value, the from part of import statement(, which typically tends to be longer) will be trimmed.


default: -1 (no limit)

3.2 Importing configuration

Nayvy detects import statement should be used by looking into
(if $XDG_CONFIG_PATH is not set, ~/.config/nayvy/import_config.nayvy)

If you set g:nayvy_import_config_path or $NAYVY_IMPORT_CONFIG_PATH, the file will be used.

You can use environment variable in the path like,

let g:nayvy_import_config_path = '$HOME/nayvy.py'

In the file, you can write any python import statements like this.

from typing import List, Optional
from pprint import pprint as pp
import sys
import os

import numpy as np

from .hoge import HogeHogeHoge as hoge

Line breaks seperating python import blocks are important,
cause nayvy determines the line where a statement inserted by it.

My own setting is here.
Feel free to copy and paste and use it.

4. Feature roadmap

  • [x] Auto imports (add and remove) based on pre-defined rules.
  • [x] Importing multiple modules using fzf.
  • [x] Touching or jumping to test script.
  • [x] Auto generating or jump to test function.
  • [x] Generating test functions using fzf.
  • [x] Providing some domain objects useful in creating ultisnips snippets.
  • [x] Providing coc custom source which can insert import statement automatically.
  • [ ] Make auto generated Test template configurable. (Now unittest, standard library, is supported)
  • [ ] Utility function of converting function arguments to docstring (for UltiSnips).

5. Philosophy

Most python code parsing algorithms of vim-nayvy is not strict, and it contains some heuristics
( In other words, it is not based on AST, or hierarchical module structure).
However, it is intentional. I personally think the heuristics works well for most real-world usecases,
and has benefit in terms of performance.
The strategy is also robust against partially broken codes.
Some code actions (such as implementing test function and jumping) should be executable
when python code in current buffer is incomplete (cannot parsed via AST, or unimportable by importlib).

Now, it is the era of LSP.
I do not think prividing aid for code completion via non-LSP plugin is demanded,
as I personally think code completion is one of the most powerful and stable features privided by LSP.
Thus, the main aim of vim-nayvy is providing a little bit utility functions :smile:

6. Note


  • Please note that any destructive change (backward incompatible) can be done without any announcement.
  • This plugin is in a very early stage of development. Feel free to report problems or submit feature requests in Issues, or make PRs.