add support for select mode. resolves #123.

autoload/airline.vim

@@ -157,7 +157,9 @@ function! airline#update_highlight()
       let l:mode = ['insert']
     elseif l:m ==# "R"
       let l:mode = ['replace']
-    elseif l:m ==? "v" || l:m ==# ""
+    elseif l:m =~# '\v(v|V|)'
+      let l:mode = ['visual']
+    elseif l:m =~# '\v(s|S|)'
       let l:mode = ['visual']
     else
       let l:mode = ['normal']

plugin/airline.vim

@@ -48,6 +48,9 @@ call s:check_defined('g:airline_mode_map', {
       \ 'V'  : 'V-LINE',
       \ 'c'  : 'CMD   ',
       \ '' : 'V-BLOCK',
+      \ 's'  : 'SELECT',
+      \ 'S'  : 'S-LINE',
+      \ '' : 'S-BLOCK',
       \ })
 
 call s:check_defined('g:airline_section_a', '%{get(g:, "airline_current_mode_text", "")}')