DetectSpellLang

Introduction

This Vim plug-in autodetects the tongue (= &spelllang) of the text in a buffer (if it is spell checked, that is, &spell is set, and &spelllang has not been explicitly set, say by a modeline :help modeline).

Installation

It uses either the spell checker aspell or hunspell (which are installed in many Linux distributions, in Mac OS, and both available for Microsoft Windows.

In Microsoft Windows the path to the executable must

• be either added to the %PATH% environment variable (say by Rapidee), or
• set by g:detectspelllang_program, say

    let g:detectspelllang_program = 'C:\Program Files (x86)\Aspell\bin\aspell.exe'

The Scoop package aspell or the Chocolatey package hunspell automatically add these to the %PATH.

Set-up

This plug-in only operates in buffers that are spell checked, that is, &l:spell is set. To ensure that certain file types, such as text, markdown and mail, are spell checked, add either the line

    autocmd FileType text,markdown,mail setlocal spell

or the line

    setlocal spell

to text.vim, markdown.vim and mail.vim in ~/.vim/ftplugin (on Microsoft Windows, in %USERPROFILE%\vimfiles\ftplugin).

The executable of the spell checker is automatically detected and preference given to aspell. You can override this automatic detection by adding to you vimrc say

    let g:detectspelllang_program = 'hunspell'

The language is detected, depending on whether aspell respectively hunspell is used, among those listed in g:detectspelllang_langs.aspell respectively g:detectspelllang_langs.hunspell. It is empty by default and has to be set by the user to a list of languages included in that of the output of the command aspell dicts respectively hunspell -D! For example,

    let g:detectspelllang_langs = {
      \ 'aspell'   : [ 'en_US', 'de_DE', 'es', 'it' ],
      \ 'hunspell' : [ 'en_US', 'de_DE', 'es_ES', 'it_IT' ],
      \ }

Please pay attention, as hunspell does, to the upper case of the suffix of the language code.

Configuration

• The value of g:detectspelllang_lines defines how many lines are tested for spelling mistakes by aspell or hunspell to derive the suitable spellcheck-language. By default

  let g:detectspelllang_lines = 1000

• The values in the dictionary 'g:detectspelllang_ftoptions' define filetype dependent options for aspell or hunspell (to specify the filter mode, for example). By default

  let g:detectspelllang_ftoptions = {
  \ 'aspell' : {
      \ 'tex'   : ['--mode=tex', '--dont-tex-check-comments'],
      \ 'html'  : ['--mode=html'],
      \ 'nroff' : ['--mode=nroff'],
      \ 'perl'  : ['--mode=perl'],
      \ 'c'     : ['--mode=ccpp'],
      \ 'cpp'   : ['--mode=ccpp'],
      \ 'sgml'  : ['--mode=sgml'],
      \ 'xml'   : ['--mode=sgml'],
      \},
  \ 'hunspell' : {
      \ 'tex'   : ['-t'],
      \ 'html'  : ['-H'],
      \ 'nroff' : ['-n'],
      \ 'odt'   : ['-O'],
      \ 'xml'   : ['-X'],
      \}
  \ }

• The value of g:detectspelllang_threshold defines the percentage of spelling mistakes among all words below which a spellcheck-language is recognized as correct. For example, with the default

  let g:detectspelllang_threshold = 20

  and g:detectspelllang_langs = [ 'en_US', 'de_DE' ], if less than 20% of all words in the buffer are spelling mistakes for 'en_US', then 'DetectSpellLang' does not verify if the percentage of spelling mistakes for 'de_DE' is below that for 'en_US'.

• The autocommand event

  User DetectSpellLangUpdate

  provides by the buffer-local variables b:detectspelllang_old and b:detectspelllang_new the previous and current value of &l:spelllang, the spell-check language. This way, a user command, for example for adding and removing abbreviations specific to a language, can hook in.

Credits

This plug-in fleshes out a gist by Arno Renevier that, later on, in May 2019, turns out to be part of a plug-in GuessLang.vim from 2011 by the same author.