LanguageTool.nvim

This plugin integrates the LanguageTool grammar checker into Vim. LanguageTool is an Open Source style and grammar checker for English, French, German, etc. See http://www.languagetool.org/languages/ for a complete list of supported languages.

LanguageTool detects grammar mistakes that a spelling checker cannot detect such as "it work" instead of "it works". LanguageTool can also detect spelling mistakes using Hunspell dictionaries bundled with LanguageTool for several languages or using morfologik for other languages. Vim builtin spelling checker can also of course be used along with LanguageTool. One advantage of the spelling checker of LanguageTool over Vim spelling checker, is that it uses the native Hunspell dictionary directly, so it works even with the latest Hunspell dictionaries containing features not supported by Vim. For example, the latest French Hunspell dictionaries from http://www.dicollecte.org are not supported by Vim, but they work well with LanguageTool. On the other hand, the Vim native spelling checker is faster and better integrated with Vim.

See http://www.languagetool.org/ for more information about LanguageTool.

Usage

Use :LanguageToolCheck to check grammar in the current buffer. This will check for grammar mistakes and highlight grammar or spelling mistakes. The location list for the buffer being checked is also populated, so you can use location commands such as :lopen to open the location list window, :lne to jump to the next error, etc.
Use :LanguageToolSummary to open a summary window where you can navigate errors using ]] and [[, jump to them by hit <CR> and fix them by hitting f on a suggestion.
Use :LanguageToolClear to remove highlighting of grammar mistakes, close the scratch window containing the list of errors, clear and close the location list.
Use :help LanguageTool to get more details on various commands and configuration information.

Some commands are also available from the menu in gvim:

Plugin -> LanguageTool -> Check
                       -> Clear

Install

Installing LanguageTool.nvim

You can use any popular plugin manager according to your preference. For example, with vim-plug, add this line in your .vimrc:

Plug 'vigoux/LanguageTool.nvim'

Download LanguageTool

To use this plugin, you need to install the Java LanguageTool grammar checker. You can choose to:

Download the standalone version of LanguageTool(LanguageTool-*.zip) from here using the orange button labeled "LanguageTool for standalone for your desktop".
or download a nightly build LanguageTool-.*-snapshot.zip from http://www.languagetool.org/download/snapshots/. It contains a more recent version than the stable version but it is not tested as well.
or checkout and build the latest LanguageTool from sources in git from https://github.com/languagetool-org/languagetool

Recent versions of LanguageTool require Java-8.

Configuration

Several global variables can be set in your .vimrc to configure the behavior of the LanguageTool plugin.

`g:languagetool_server`

This variable specifies the location of the LanguageTool java grammar checker program. Default is empty. Example:

:let g:languagetool_server='$HOME/languagetool/languagetool-standalone/target/LanguageTool-3.7-SNAPSHOT/LanguageTool-3.7-SNAPSHOT/languagetool-server.jar'

`g:languagetool`

All LanguageTool configuration goes through this varaible, which is organized as follows (all lists are comma separated):

    g:languagetool = {
        '.' : {
            {model1} for all filetypes
        },
        'my_filetype' : {
            {model1} for my_filetype
        }
    }

    {model1} = {
        'enabledRules' : "list,of,enabled,rules",
        'disabledRules' : "list,of,disabled,rules",
        'enabledCategories' : "list,of,enabled,categories",
        'disabledCategories' : "list,of,disabled,categories",
        'language' : "the code of the language to check,
            as given by :LanguageToolSupportedLanguages"
    }

Actually, there are more options than those found here, you can found an exhaustive list here : https://languagetool.org/http-api/swagger-ui/#!/default/post_check

Colors

You can customize the following syntax highlighting groups:

LanguageToolCmd
LanguageToolErrorCount
LanguageToolLabel
LanguageToolUrl
LanguageToolGrammarError
LanguageToolSpellingError

For example, to highlight grammar mistakes in blue, and spelling mistakes in red, with a curly underline in vim GUIs that support it, add this into your colorscheme:

hi LanguageToolGrammarError  guisp=blue gui=undercurl guifg=NONE guibg=NONE ctermfg=white ctermbg=blue term=underline cterm=none
hi LanguageToolSpellingError guisp=red  gui=undercurl guifg=NONE guibg=NONE ctermfg=white ctermbg=red  term=underline cterm=none

Mappings

LanguageTool.nvim provides <Plug> mappings for a more convenient usage.

<Plug>(LanguageToolCheck) can be used in both normal and insert modes to run a check on current buffer.

Events

LanguageTool.nvim triggers some User events:

LanguageToolCheckDone, which is triggered right after a check is done
LanguageToolServerStarted, which is triggered right after the server has started

FAQ

I want the summary window to open whenever a check is done.

Just add the following lines to you .vimrc:

autocmd User LanguageToolCheckDone LanguageToolSummary

I want the server to start whenever I open a certain filetype

Add this to your .vimrc (this example is for latex files)

autocmd Filetype tex LanguageToolSetUp

I have a local LanguageTool server running, I do not want to start a new instance

You can set g:languagetool_server_command to something that prints "Server Started"

let g:languagetool_server_command='echo "Server Started"'

License

The VIM LICENSE applies to the LanguageTool.nvim plugin (see :help copyright but replace "LanguageTool.nvim" with "Vim").

LanguageTool is freely available under LGPL.

vigoux / LanguageTool.nvim

readme