Make function run only on specific filetype

Question

So i have a specific function I'd like to edit in my .vimrc, so that it work only on specific filetype (eg: .vim).

The code for this example is taken from this answer.

function OrgFold(lnum)
  let level = strlen(matchstr(getline(a:lnum), '\v^\s*\zs\"+\t'))
  if level > 0
    return '>'.level
  else
    return '='
  endif
endfunction

The above function essentially work on all files, but i want to know how to only make it work for .vim or whatever filetype i specify.

Answer 1

One solution is to use a filetype plugin (:h ftplugin).

First, you need to enable them with filetype plugin on (in your vimrc).

Then, you can add a file in vim/after/ftplugin/FILETYPE.vim, replacing FILETYPE with what's needed.

This file will then be sourced by vim for each file matching the filetype, allowing them to use whatever is in your plugin.

Drop your function there to make it available for this specific filetype only.