Global variable not updated by function called in (run (begin ...))

[David Hull <dmh@tibco.com>]

% scsh
Scsh 0.4
> (define foo 0)
> (define (inc-foo!)
        (set! foo (+ foo 1))
        (format #t "Foo is ~a\n" foo))
> foo
0
> (inc-foo!)
Foo is 1
#f
> foo
1
> (run (begin (inc-foo!)))
Foo is 2
0
> foo
1

This is puzzling at best.  Evidently, inside the (run (begin ...))
form, inc-foo! sees a copy of foo, not the global itself.  Is this
deliberate?  Is it penance for side-effecting a global variable?

Wait a sec, I just thought of something

> (run (begin
        (define foo 123)
        (inc-foo!)
        (format #t "Foo inside run is ~a\n" foo)))
Foo is 2
Foo inside run is 123
0
> foo
1

Obviously, *something* is getting incremented . . .

--dmh