[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
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: <m3boz09j6l.fsf@unquote.localdomain>
- References: <m3tycs9znp.fsf@unquote.localdomain> <4DD39D16.7060704@snell-pym.org.uk> <m3boz09j6l.fsf@unquote.localdomain>
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"
>
> and
>
> "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...
> Andy
ABS
--
Alaric Snell-Pym
http://www.snell-pym.org.uk/alaric/
_______________________________________________
Scheme-reports mailing list
Scheme-reports@x
http://lists.scheme-reports.org/cgi-bin/mailman/listinfo/scheme-reports