[racket] try/catch/finally idiom in Racket

OK, thanks.  I will take a look at these continuation prompts.  Don't 
recall seeing them before.

Robby Findler wrote at 10/08/2010 08:25 PM:
> Probably you wanted a prompt in that case.
>
> Robby
>
> On Friday, October 8, 2010, Neil Van Dyke <neil at neilvandyke.org> wrote:
>   
>> Should "racket/base" include something like "unwind-protect"?
>>
>> The documentation could warn about what this restricts.
>>
>> I feel bad every time I use "dynamic-wind" to approximate "unwind-protect", pretending that I don't have first-order continuations.  But often I'm cleaning up one-shot external resources anyway.  "unwind-protect" would be more explicit about the assumptions than "dynamic-wind" would, and incidentally would be tidier in the code.
>>
>> Jay McCarthy wrote at 10/08/2010 07:40 PM:
>>
>> I use dynamic-wind for this. If there is something better, I don't know what it is. dynamic-wind is a little bit funny though because if you capture continuations then the in/out handlers can run multiple times which might defy your expectations. You could set up a continuation barrier on the inside to ensure that doesn't happen though.
>>     

-- 
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