added persistent undo

.vimrc

@@ -54,6 +54,9 @@
 
 	" Setting up the directories {
 		set backup 						" backups are nice ...
+		set undofile					" so is persistent undo ...
+		set undolevels=1000 "maximum number of changes that can be undone
+		set undoreload=10000 "maximum number lines to save for undo on a buffer reload
         " Moved to function at bottom of the file
 		"set backupdir=$HOME/.vimbackup//  " but not when they clog .
 		"set directory=$HOME/.vimswap// 	" Same for swap files
@@ -437,7 +440,8 @@ function! InitializeDirectories()
   let dir_list = { 
 			  \ 'backup': 'backupdir', 
 			  \ 'views': 'viewdir', 
-			  \ 'swap': 'directory' }
+			  \ 'swap': 'directory', 
+			  \ 'undo': 'undodir' }
 
   for [dirname, settingname] in items(dir_list)
 	  let directory = parent . '/' . prefix . dirname . "/"