+ method lockScript offset =
+ let mark = `MARK locked_mark in
+ script_buf#move_mark mark ~where:(script_buf#get_iter_at_char offset);
+ script_buf#remove_tag locked_tag ~start:script_buf#start_iter
+ ~stop:script_buf#end_iter;
+ script_buf#apply_tag locked_tag ~start:script_buf#start_iter
+ ~stop:(script_buf#get_iter_at_mark mark)
+