add rbenv integration, closes millermedeiros#15. add safe checks to a…

…ll plugins.

doc/statline.txt

@@ -45,6 +45,13 @@ See |'syntastic_stl_format'| for customization info.
     let g:statline_rvm = 1
 <
 
+------------------------------------------------------------------------------
+                                                            *'statline_rbenv'*
+
+|rbenv| integration is disabled by default, to enable it: >
+    let g:statline_rbenv = 1
+<
+
 ------------------------------------------------------------------------------
                                                    *'statline_show_n_buffers'*
 
@@ -176,7 +183,13 @@ Next
     - Add |'statline_show_charcode'| (@knl)
     - Add |'statline_no_encoding_string'| (@knl)
     - Add |'statline_show_n_buffers'| [#2]
+    - Add |'statline_rbenv'| [#15]
     - Fix problem with non-utf8 encoding. [#13]
+    - Create |augroup| to wrap all |autocmd| and make sure commands are cleared
+      before adding new ones, avoids setting same command multiple times.
+    - Add safe checks to all plugins to make sure they aren't called if they
+      don't exist, make it more portable since users may copy vimrc files that
+      enable plugin integration.
 
 
 ------------------------------------------------------------------------------

plugin/statline.vim

@@ -140,7 +140,17 @@ if !exists('g:statline_rvm')
     let g:statline_rvm = 0
 endif
 if g:statline_rvm
-    set statusline+=%{rvm#statusline()}
+    set statusline+=%{exists('g:loaded_rvm')?rvm#statusline():''}
+endif
+
+
+" ---- rbenv ----
+
+if !exists('g:statline_rbenv')
+    let g:statline_rbenv = 0
+endif
+if g:statline_rbenv
+    set statusline+=%{exists('g:loaded_rbenv')?rbenv#statusline():''}
 endif
 
 
@@ -150,7 +160,7 @@ if !exists('g:statline_fugitive')
     let g:statline_fugitive = 0
 endif
 if g:statline_fugitive
-    set statusline+=%4*%{fugitive#statusline()}%*
+    set statusline+=%4*%{exists('g:loaded_fugitive')?fugitive#statusline():''}%*
 endif
 
 
@@ -160,18 +170,9 @@ if !exists('g:statline_syntastic')
     let g:statline_syntastic = 1
 endif
 if g:statline_syntastic
-    set statusline+=\ %3*%{StatlineSyntastic()}%*
+    set statusline+=\ %3*%{exists('g:loaded_syntastic_plugin')?SyntasticStatuslineFlag():''}%*
 endif
 
-function! StatlineSyntastic()
-    " safe guard against syntastic being only loaded after statline
-    if exists('g:loaded_syntastic_plugin')
-        return SyntasticStatuslineFlag()
-    else
-        return ''
-    endif
-endfunction
-
 
 
 " ====== custom errors ======