Welcome to MzScheme version 360, Copyright (c) 2004-2006 PLT Scheme Inc.
> > 
#<procedure:...les/withdraw.scm:2:2>
> (define a (make-decr 100))
> a
#<procedure:...les/withdraw.scm:2:2>
> (a 10)
90
> (a 20)
80
> (a 100)
0
> (a 100)
0
> > (define b (make-withdraw 100))
> b
#<procedure:...les/withdraw.scm:6:2>
> (b 10)
90
> (b 10)
80
> (b 10)
70
> (b 10)
60
> (b 10)
50
> (set! w 2)
set!: cannot set undefined identifier: w

 === context ===
repl-loop

> (set! a 2)
> (set! spam 2)
set!: cannot set undefined identifier: spam

 === context ===
repl-loop

> (define spam 1)
> (set! spam 2)
> spam
2
> (define a '(1 2 3 4))
> a
(1 2 3 4)
> (set! a (cdr a))
> a
(2 3 4)
> (set! b (cdr a))
> b
(3 4)
> (define b (make-withdraw 100))
> (define c (make-withdraw 100))
> (b 10)
90
> (c 10)
90
> a
(2 3 4)
> b
#<procedure:...les/withdraw.scm:6:2>
> (set! b (cdr a))
> a
(2 3 4)
> b
(3 4)
> (eq? b (cdr a))
#t
> (set! (cdr a) 6)
stdin::559: set!: not an identifier at: (cdr a) in: (set! (cdr a) 6)

 === context ===
repl-loop

> (define a 9)
> a
9
> b
(3 4)
> (set-car! b 7)
> b
(7 4)
> a
9
> (define a '(1 2 3 4))
> (define b (cdr a))
> a
(1 2 3 4)
> b
(2 3 4)
> (set-car! b 8)
> b
(8 3 4)
> a
(1 8 3 4)
> (set-cdr! a 6)
> a
(1 . 6)
> b
(8 3 4)
>