[racket-dev] Removing Xexpr preference from Web Server

You've made a contract that isn't a projection, but does a coercion?

I'd be happier if you instead made your own separate wrappers and
didn't use "/c" and didn't call this a contract.

Robby

On Sun, Dec 5, 2010 at 12:29 AM, Jay McCarthy <jay.mccarthy at gmail.com> wrote:
> Giving special consideration to Eli and YC's perspectives, I've come up with
> the following way out of this problem.
> I found a way to provide a global hook that is tasteful to me. I've created
> "dynamic/c". Here's a little example:
> Examples:
>   (define p (make-parameter any/c))
>   (define c (dynamic/c string? p number?))
>   > (contract c "123" 'pos 'neg)
>   pos broke the contract
>     (dynamic
>      string?
>      #<procedure:parameter-procedure>
>      number?)
>    on eval:5:0; expected <number?>, given: "123"
>   > (p (coerce/c string->number))
>   > (contract c "123" 'pos 'neg)
>   123
>   > (contract c "123a" 'pos 'neg)
>   pos broke the contract
>     (dynamic
>      string?
>      #<procedure:parameter-procedure>
>      number?)
>    on eval:8:0; Coercion failed
> The Web Server will define response/c as (dynamic/c any/c current-response/c
> response?) and provide the current-response/c parameter for customization.
> The default will be no coercion, but Xexpr conversion will be easily
> accessible. A compatibility library will automatically set
> current-response/c appropriately.
> Attached is the new compatibility README.
> I hope this will satisfy all.
> Jay
>
> --
> Jay McCarthy <jay at cs.byu.edu>
> Assistant Professor / Brigham Young University
> http://faculty.cs.byu.edu/~jay
>
> "The glory of God is Intelligence" - D&C 93
>
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