Yes, this idea has a different result. With the contract it is not possible to use parameterize to change the value of the parameter locally, like in the function "quietly" of the example.
The same effect can be obtained using a guard: (define my-curr-out-port (make-parameter (current-output-port) (lambda (v) (error 'my-curr-out-port)))) Gustavo On Mon, Feb 11, 2013 at 8:25 PM, Danny Yoo <[email protected]> wrote: >> Perhaps you can use contracts to enforce this? > > Oh, wait: I didn't pay attention to the error message at all. My > apologies! So nope, my approach doesn't work here... I'll think > about this some more. ____________________ Racket Users list: http://lists.racket-lang.org/users
