anchor.diff:                  PreviousSearch : string option
           
                   // Used to implement the Kill semantics (multiple Alt-Ds accumulate)
  -                LastCommand : Command
  +                LastCommand : Command option
               }
   
           let makeDefaultLineEditorState (name : string option) (histsize : int) =
  
positive.code:                         // The cursor is at the end of the string
                          let p = st.Text.LastIndexOf (search.Term)
                          if p <> -1 then
                              searchState <- Some({ search with MatchAt = p })
                              cursor <- p
                              x.ForceCursor st.Cursor
                              search_backward <- false
                      else
  
negative.code: 
              member private x.SearchAppend (c:char) search =
                  let newTerm = search.Term + (string)c
                  st <- { st with SearchState = Some { search with Term = newTerm } }
                  x.SetSearchPrompt newTerm
  
                  //
  