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Re: [Scheme-reports] 4.2.7. Exception Handling
- To: Andy Wingo <wingo@x>
- Subject: Re: [Scheme-reports] 4.2.7. Exception Handling
- From: Alaric Snell-Pym <alaric@x>
- Date: Wed, 18 May 2011 15:39:48 +0100
- Cc: scheme-reports@x
- In-reply-to: <firstname.lastname@example.org>
- References: <email@example.com> <4DD39D16.firstname.lastname@example.org> <email@example.com>
On 05/18/11 15:28, Andy Wingo wrote:
> Are you sure? :-) The spec notes:
> "That implicit `cond' expression is evaluated with the continuation
> and dynamic extent of the `guard' expression"
> "The final expression in a <cond> clause is in a tail context if the
> `guard' expression itself is."
Hrm, OK, it looks like that evolved a bit from my original simplistic
proposal! I'll take a look at the wording there and make sure it's as
intended, when I get a moment.
In which case, the re-raise if no clause matches would rely on having
preserved the original dynamic state by keeping a copy of the
continuation of RAISE around. Or, rather, a continuation captured just
within RAISE before the handler is invoked that, if it actually
continues, causes the re-raise - having re-wound the dynamic state...
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