Yank and Put

 All the deleting, undeleting and copying in this editor is acheived by the
 use of the 'Yank and Put' paradigm, as in UNIX vi(1).

 For the datatypes character, line, and block there are commands to delete
 them. When they are deleted, they are put on a deleted item stack.

 eg:  character_delete_left
      line_delete
      block_delete

 This means they can be retrieved by the use of an undelete function.

 Alternatively lines and blocks may be yanked. This makes a copy and puts
 the copy on the deleted stack. These copies may be retrieved by an undelete
 function.

 eg:  line_yank
      block_yank

 Deleted items can be undeleted by the other_undelete function. This pops the
 most recently deleted item from the deleted item stack and attempts to
 replace it in the current buffer.

 Alternatively the item on the top of the stack may be duplicated and the
 duplicated item will be inserted into the current buffer. This is done with
 the other_put command.