On Sat, Jan 15, 2011 at 12:49 AM, Eric Dobson <endob...@cs.brown.edu> wrote: > I was looking at the documentation on how continuation-marks work, and > the documented behavior is different than what I observed. > > The following programs add a continuation mark, then a prompt, then > try to look at the current continuation marks. According to the > documentation I would expect the programs not to find a continuation > mark, but in some cases it does. Here are the 6 variations and their > returned values. > > > #lang racket > (define key 'key) > (define value 'value) > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > #f > key)))) > > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > (current-continuation-marks) > key)))) > > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > (current-continuation-marks (default-continuation-prompt-tag)) > key)))) > > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > #f > key > (default-continuation-prompt-tag))))) > > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > (current-continuation-marks) > key > (default-continuation-prompt-tag))))) > > (with-continuation-mark key value > (call-with-continuation-prompt > (lambda () > (continuation-mark-set-first > (current-continuation-marks (default-continuation-prompt-tag)) > key > (default-continuation-prompt-tag))))) > > => > 'value > #f > #f > 'value > #<continuation-prompt-tag:default> > #<continuation-prompt-tag:default> >
FWIW, the non-false results seem wrong to me too. _________________________________________________ For list-related administrative tasks: http://lists.racket-lang.org/listinfo/users
