backward-sexp

• (send a-mred:scheme-mode backward-sexp edit start move?) -> void
      edit : a mred:media-edit% object
      start : int
      move? : boolean

  Moves backward over the S-expression ending at position start. If move? is #f, the caret is not actually moved, but the S-expression's starting position is flashed. (This is useful for flashing a matching parenthesis.)