5 This directory includes an example program for extending Guile with a
6 new (and even useful) data type.
11 To build the example, simply type
17 The resulting `box' program is a Guile interpreter which has one
18 additional data type called `box'.
23 A box is simply an object for storing one other object in. It can be
24 used for passing parameters by reference, for example. You simply
25 store an object into a box, pass it to another procedure which can
26 store a new object into it and thus return a value via the box.
31 Box objects are created with `make-box', set with `box-set!' and
32 examined with `box-ref'. See the following example session for usage
39 guile> (define b (make-box))
42 guile> (box-set! b '(list of values))
44 #<box (list of values)>