Improve easytags_dynamic_files implementation (best of both worlds?)

Some users want the plug-in to use existing project specific tags files
but fall back to the global tags file or a file type specific tags file
if a project specific tags file does not exist. Other users want the
plug-in to automatically create project specific tags files. Both are
reasonable options to have. I hope with this change we can all
be happy :-) (see also issue #15 and issue #16 on GitHub).

3 files changed, 28 insertions, 20 deletions

diff --git a/README.md b/README.md
index 07d2903..1a9cc98 100644
--- a/README.md
+++ b/README.md
@@ -64,17 +64,16 @@ A leading `~` in the `g:easytags_file` variable is expanded to your current home
 
 ### The `g:easytags_dynamic_files` option
 
-By default `:UpdateTags` only writes to the global tags file. If you use the following setting to enable project specific tags files:
+By default `:UpdateTags` only writes to the global tags file, but it can be configured to look for project specific tags files by adding the following lines to your [vimrc script] [vimrc]:
 
     :set tags=./tags;
-
-You can enable this option so that the project specific tags files are written instead of the global tags file:
-
     :let g:easytags_dynamic_files = 1
 
-When you enable this option, the easytags plug-in will expand the ['tags' option] [tags_opt] and use the first filename (whether the file exists or not). The tags option is reevaluated each time the plug-in runs, so the results can differ depending on the location of the current buffer or working directory.
+You can change the name of the tags file, the important thing is that it's relative to your working directory or the buffer (using a leading `./`). When `g:easytags_dynamic_files` is set to 1 the easytags plug-in will write to the first existing tags file seen by Vim (based on the ['tags' option] [tags_opt]). In other words: If a project specific tags file is found it will be used, otherwise the plug-in falls back to the global tags file (or a file type specific tags file).
+
+If you set `g:easytags_dynamic_files` to 2 the easytags plug-in will automatically create project specific tags based on the first name in the 'tags' option. This disables the global tags file and file type specific tags files.
 
-Note that this option takes precedence over `g:easytags_by_filetype`.
+The ['tags' option] [tags_opt] is reevaluated each time the plug-in runs, so which tags file is selected can differ depending on the buffer and working directory.
 
 ### The `g:easytags_by_filetype` option
 
diff --git a/autoload/xolox/easytags.vim b/autoload/xolox/easytags.vim
index 5c5334e..39102e2 100644
--- a/autoload/xolox/easytags.vim
+++ b/autoload/xolox/easytags.vim
@@ -3,7 +3,7 @@
 " Last Change: September 5, 2011
 " URL: http://peterodding.com/code/vim/easytags/
 
-let g:xolox#easytags#version = '2.5.6'
+let g:xolox#easytags#version = '2.5.7'
 
 " Public interface through (automatic) commands. {{{1
 
@@ -530,7 +530,10 @@ endfunction
 function! xolox#easytags#get_tagsfile() " {{{2
   let tagsfile = ''
   " Look for a suitable project specific tags file?
-  if xolox#misc#option#get('easytags_dynamic_files', 0)
+  let dynamic_files = xolox#misc#option#get('easytags_dynamic_files', 0)
+  if dynamic_files == 1
+    let tagsfile = get(tagfiles(), 0, '')
+  elseif dynamic_files == 2
     let tagsfile = xolox#misc#option#eval_tags(&tags, 1)
   endif
   " Check if a file type specific tags file is useful?
diff --git a/doc/easytags.txt b/doc/easytags.txt
index 40e06f4..0ffb508 100644
--- a/doc/easytags.txt
+++ b/doc/easytags.txt
@@ -139,22 +139,28 @@ home directory ('$HOME' on UNIX, '%USERPROFILE%' on Windows).
 -------------------------------------------------------------------------------
 The *g:easytags_dynamic_files* option
 
-By default |:UpdateTags| only writes to the global tags file. If you use the
-following setting to enable project specific tags files:
+By default |:UpdateTags| only writes to the global tags file, but it can be
+configured to look for project specific tags files by adding the following
+lines to your |vimrc| script:
 >
     :set tags=./tags;
-
-You can enable this option so that the project specific tags files are written
-instead of the global tags file:
->
     :let g:easytags_dynamic_files = 1
 
-When you enable this option, the easytags plug-in will expand the |'tags'|
-option and use the first filename (whether the file exists or not). The tags
-option is reevaluated each time the plug-in runs, so the results can differ
-depending on the location of the current buffer or working directory.
-
-Note that this option takes precedence over |g:easytags_by_filetype|.
+You can change the name of the tags file, the important thing is that it's
+relative to your working directory or the buffer (using a leading './'). When
+|g:easytags_dynamic_files| is set to 1 the easytags plug-in will write to the
+first existing tags file seen by Vim (based on the |'tags'| option). In other
+words: If a project specific tags file is found it will be used, otherwise the
+plug-in falls back to the global tags file (or a file type specific tags
+file).
+
+If you set |g:easytags_dynamic_files| to 2 the easytags plug-in will
+automatically create project specific tags based on the first name in the
+'tags' option. This disables the global tags file and file type specific tags
+files.
+
+The |'tags'| option is reevaluated each time the plug-in runs, so which tags
+file is selected can differ depending on the buffer and working directory.
 
 -------------------------------------------------------------------------------
 The *g:easytags_by_filetype* option