Add g:easytags_opts option (issue #98)

See also issue #98 on GitHub:
  #98

README.md

@@ -62,6 +62,10 @@ The plug-in will try to determine the location where Exuberant Ctags is installe
 
 If you rely entirely on language-specific configuration and don't have a general ctags program, set this to the empty string.
 
+### The `g:easytags_opts` option
+
+If you need to pass custom command line option(s) to the program specified by `g:easytags_cmd` you can set this option to a list of strings to be passed to Exuberant Ctags. Make sure to only use options that are valid in any context, for example the concatenation of `g:easytags_cmd`, `g:easytags_opts` and `--list-languages` should work as expected.
+
 ### The `g:easytags_async` option
 
 By default vim-easytags runs Exuberant Ctags and updates your tags file in the foreground, blocking Vim in the process. As your tags files get larger this becomes more annoying. It has been the number one complaint about vim-easytags since I published the first release online.

autoload/xolox/easytags.vim

@@ -1,9 +1,9 @@
 " Vim script
 " Author: Peter Odding <peter@peterodding.com>
-" Last Change: November 3, 2014
+" Last Change: November 13, 2014
 " URL: http://peterodding.com/code/vim/easytags/
 
-let g:xolox#easytags#version = '3.8.3'
+let g:xolox#easytags#version = '3.9'
 let g:xolox#easytags#default_pattern_prefix = '\C\<'
 let g:xolox#easytags#default_pattern_suffix = '\>'
 
@@ -239,15 +239,17 @@ function! s:prep_cmdline(cfile, tagsfile, arguments) " {{{3
   let custom_languages = xolox#misc#option#get('easytags_languages', {})
   let language = get(custom_languages, vim_file_type, {})
   if empty(language)
-    let program = xolox#misc#option#get('easytags_cmd')
-    let cmdline = [program, '--fields=+l', '--c-kinds=+p', '--c++-kinds=+p']
+    let cmdline = [xolox#easytags#ctags_command()]
+    call add(cmdline, '--fields=+l')
+    call add(cmdline, '--c-kinds=+p')
+    call add(cmdline, '--c++-kinds=+p')
     call add(cmdline, '--sort=no')
     call add(cmdline, '-f-')
     if xolox#misc#option#get('easytags_include_members', 0)
       call add(cmdline, '--extra=+q')
     endif
   else
-    let program = get(language, 'cmd', xolox#misc#option#get('easytags_cmd'))
+    let program = get(language, 'cmd', xolox#easytags#ctags_command())
     if empty(program)
       call xolox#misc#msg#warn("easytags.vim %s: No 'cmd' defined for language '%s', and also no global default!", g:xolox#easytags#version, vim_file_type)
       return
@@ -431,6 +433,20 @@ let s:invalid_keywords = {
 
 " Public supporting functions (might be useful to others). {{{1
 
+function! xolox#easytags#ctags_command() " {{{2
+  let program = xolox#misc#option#get('easytags_cmd')
+  if !empty(program)
+    let options = xolox#misc#option#get('easytags_opts')
+    if !empty(options)
+      let command_line = [program]
+      call extend(command_line, map(copy(options), 'xolox#misc#escape#shell(v:val)'))
+      let program = join(command_line)
+    endif
+    return program
+  endif
+  return ''
+endfunction
+
 function! xolox#easytags#get_tagsfile() " {{{2
   let tagsfile = ''
   " Look for a suitable project specific tags file?

autoload/xolox/easytags/filetypes.vim

@@ -1,6 +1,6 @@
 " Vim script
 " Author: Peter Odding <peter@peterodding.com>
-" Last Change: October 21, 2014
+" Last Change: November 13, 2014
 " URL: http://peterodding.com/code/vim/easytags/
 
 " This submodule of the vim-easytags plug-in translates between back and forth
@@ -87,10 +87,11 @@ function! s:discover_supported_filetypes() " {{{1
   " Initialize predefined groups & mappings and discover supported file types.
   if !s:discovered_filetypes
     " Discover the file types supported by Exuberant Ctags?
-    if !empty(g:easytags_cmd)
+    let command_line = xolox#easytags#ctags_command()
+    if !empty(command_line)
       let starttime = xolox#misc#timer#start()
-      let command = g:easytags_cmd . ' --list-languages'
-      for line in xolox#misc#os#exec({'command': command})['stdout']
+      let command_line .= ' --list-languages'
+      for line in xolox#misc#os#exec({'command': command_line})['stdout']
         if line =~ '\[disabled\]$'
           " Ignore languages that have been explicitly disabled using `--languages=-Vim'.
           continue

doc/easytags.txt

@@ -11,23 +11,24 @@ Contents ~
   2. The |:HighlightTags| command
  4. Options                                                  |easytags-options|
   1. The |g:easytags_cmd| option
-  2. The |g:easytags_async| option
-  3. The |g:easytags_syntax_keyword| option
-  4. The |g:easytags_languages| option
-  5. The |g:easytags_file| option
-  6. The |g:easytags_dynamic_files| option
-  7. The |g:easytags_by_filetype| option
-  8. The |g:easytags_events| option
-  9. The |g:easytags_always_enabled| option
-  10. The |g:easytags_on_cursorhold| option
-  11. The |g:easytags_updatetime_min| option
-  12. The |g:easytags_auto_update| option
-  13. The |g:easytags_auto_highlight| option
-  14. The |g:easytags_autorecurse| option
-  15. The |g:easytags_include_members| option
-  16. The |g:easytags_resolve_links| option
-  17. The |g:easytags_suppress_ctags_warning| option
-  18. The |g:easytags_suppress_report| option
+  2. The |g:easytags_opts| option
+  3. The |g:easytags_async| option
+  4. The |g:easytags_syntax_keyword| option
+  5. The |g:easytags_languages| option
+  6. The |g:easytags_file| option
+  7. The |g:easytags_dynamic_files| option
+  8. The |g:easytags_by_filetype| option
+  9. The |g:easytags_events| option
+  10. The |g:easytags_always_enabled| option
+  11. The |g:easytags_on_cursorhold| option
+  12. The |g:easytags_updatetime_min| option
+  13. The |g:easytags_auto_update| option
+  14. The |g:easytags_auto_highlight| option
+  15. The |g:easytags_autorecurse| option
+  16. The |g:easytags_include_members| option
+  17. The |g:easytags_resolve_links| option
+  18. The |g:easytags_suppress_ctags_warning| option
+  19. The |g:easytags_suppress_report| option
  5. Customizing the easytags plug-in             |customizing-easytags-plug-in|
   1. Passing custom command line arguments to Exuberant Ctags |easytags-passing-custom-command-line-arguments-to-exuberant-ctags|
   2. Update & highlight tags immediately after save |easytags-update-highlight-tags-immediately-after-save|
@@ -186,6 +187,15 @@ you've installed Exuberant Ctags, e.g.:
 If you rely entirely on language-specific configuration and don't have a
 general ctags program, set this to the empty string.
 
+-------------------------------------------------------------------------------
+The *g:easytags_opts* option
+
+If you need to pass custom command line option(s) to the program specified by
+|g:easytags_cmd| you can set this option to a list of strings to be passed to
+Exuberant Ctags. Make sure to only use options that are valid in any context,
+for example the concatenation of |g:easytags_cmd|, |g:easytags_opts| and
+'--list-languages' should work as expected.
+
 -------------------------------------------------------------------------------
 The *g:easytags_async* option