Add code to ask user for confirmation in vimsupport

python/vimsupport.py

@@ -59,6 +59,34 @@ def PostVimMessage( message ):
                .format( EscapeForVim( message ) ) )
 
 
+def PresentDialog( message, choices, default_choice_index = 0 ):
+  """Presents the user with a dialog where a choice can be made.
+  This will be a dialog for gvim users or a question in the message buffer
+  for vim users or if `set guioptions+=c` was used.
+
+  choices is list of alternatives.
+  default_choice_index is the 0-based index of the default element
+  that will get choosen if the user hits <CR>. Use -1 for no default.
+
+  PresentDialog will return a 0-based index into the list
+  or -1 if the dialog was dismissed by using <Esc>, Ctrl-C, etc.
+
+  See also:
+    :help confirm() in vim (Note that vim uses 1-based indexes)
+
+  Example call:
+    PresentDialog("Is this a nice example?", ["Yes", "No", "May&be"])
+      Is this a nice example?
+      [Y]es, (N)o, May(b)e:"""
+  to_eval = "confirm('{0}', '{1}', {2})".format( EscapeForVim( message ),
+    EscapeForVim( "\n" .join( choices ) ), default_choice_index + 1 )
+  return int( vim.eval( to_eval ) ) - 1
+
+
+def Confirm( message ):
+  return bool( PresentDialog( message, [ "Ok", "Cancel" ] ) == 0 )
+
+
 def EchoText( text ):
   def EchoLine( text ):
     vim.command( "echom '{0}'".format( EscapeForVim( text ) ) )