3.11 Boxes

A box is like a single-element vector. It can print as a quoted #& followed by the printed form of the boxed value. A #& form can also be used as an expression, but since the resulting box is constant, it has practically no use.


  > (define b (box "apple"))
  > b


  > (unbox b)


  > (set-box! b '(banana boat))
  > b

  '#&(banana boat)

+Boxes in Reference: Racket provides more on boxes and box procedures.