[racket] Read-only parameters

From: Gustavo Massaccesi (gustavo at oma.org.ar)
Date: Mon Feb 11 20:56:49 EST 2013

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))))


On Mon, Feb 11, 2013 at 8:25 PM, Danny Yoo <dyoo at hashcollision.org> 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.

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