Added PlugConfig command

The PlugConfig command allows to create a file per plugin with the
settings for the plugin. It is loaded after the plugin has been loaded.

doc/plug.txt

@@ -199,6 +199,7 @@ Reload .vimrc and `:PlugInstall` to install plugins.
   `PlugStatus`                         | Check the status of plugins
   `PlugDiff`                           | Examine changes from the previous update and the pending changes
   `PlugSnapshot[!] [output path]`      | Generate script for restoring the current snapshot of the plugins
+  `PlugConfig`                         | Edit configuration of plugin
  ------------------------------------+-------------------------------------------------------------------
 
 
@@ -235,6 +236,7 @@ Reload .vimrc and `:PlugInstall` to install plugins.
   `g:plug_window`      |  `vertical topleft new`             | Command to open plug window
   `g:plug_pwindow`     |  `above 12new`                      | Command to open preview window in  `PlugDiff`
   `g:plug_url_format`  |  `https://git::@github.com/%s.git`  |  `printf`  format to build repo URL (Only applies to the subsequent  `Plug`  commands)
+  `g:plug_config_dirs` | ['~/.vim/configs']                | Directories to lookup plugin specific configs, first one is used to create new
  --------------------+-----------------------------------+-----------------------------------------------------------------------------------
 
 

plug.vim

@@ -141,6 +141,7 @@ function! s:define_commands()
   endif
   command! -nargs=* -bar -bang -complete=customlist,s:names PlugInstall call s:install(<bang>0, [<f-args>])
   command! -nargs=* -bar -bang -complete=customlist,s:names PlugUpdate  call s:update(<bang>0, [<f-args>])
+  command! -nargs=1 -bar -complete=customlist,s:names PlugConfig call s:edit_config(<f-args>)
   command! -nargs=0 -bar -bang PlugClean call s:clean(<bang>0)
   command! -nargs=0 -bar PlugUpgrade if s:upgrade() | execute 'source' s:esc(s:me) | endif
   command! -nargs=0 -bar PlugStatus  call s:status()
@@ -284,6 +285,7 @@ function! plug#end()
   else
     call s:reload_plugins()
   endif
+  call s:load_all_configs()
 endfunction
 
 function! s:loaded_names()
@@ -494,6 +496,7 @@ function! s:lod(names, types, ...)
       endif
       call s:source(rtp, a:2)
     endif
+    call s:load_config(name)
     call s:doautocmd('User', name)
   endfor
 endfunction
@@ -600,6 +603,51 @@ function! s:update(force, names)
   call s:update_impl(1, a:force, a:names)
 endfunction
 
+function! s:get_config_path(name, create)
+  " uniform name, remove vim prefix
+  let l:pluginconfig = tolower(a:name).'.vim'
+  if !exists('s:config_dirs')
+    let s:config_dirs = get(g:, 'plug_config_dirs', [split(&rtp, ',')[0] . '/configs'])
+  endif
+  " look in paths for file, else use first one as default
+  for path in s:config_dirs
+    let l:file = glob(path.'/'.l:pluginconfig)
+    if filereadable(l:file)
+      return l:file
+    endif
+  endfor
+  if a:create && len(s:config_dirs) > 0
+    if !isdirectory(s:config_dirs[0])
+      try
+        call mkdir(s:config_dirs[0], 'p')
+      catch
+        return ''
+      endtry
+    endif
+    return s:config_dirs[0].'/'.l:pluginconfig
+  else
+    return ''
+  endif
+endfunction
+
+function! s:edit_config(name)
+  let l:file = s:get_config_path(a:name, 1)
+  exe 'tabedit ' . l:file
+endfunction
+
+function! s:load_config(name)
+  let l:file = s:get_config_path(a:name, 0)
+  if l:file != '' && filereadable(l:file)
+    exe 'source ' . l:file
+  endif
+endfunction
+
+function! s:load_all_configs()
+  for plug in filter(keys(s:loaded), 's:loaded[v:val] == 1')
+    call s:load_config(plug)
+  endfor
+endfunction
+
 function! plug#helptags()
   if !exists('g:plugs')
     return s:err('plug#begin was not called')