Re: [Chicken-hackers] [PATCH] add R7RS support for exit and emergency-exit

[Peter Bex]

On Tue, May 28, 2013 at 04:24:08AM -0700, Evan Hanson wrote:
> This patch adds (I believe) almost-R7RS support for the `exit` and
> `emergency-exit` procedures.

Thanks for posting.  However, I think this can be safely put into the
r7rs egg, it doesn't look like anything that's required to be put
into core.

> I think I've gotten these right, but they should obviously be looked at
> carefully. If you can't trust software to stop, can you trust it at all?

One of the advantages of doing it in the egg is that you can get it
wrong, and we can more quickly push a new release.  Core moves at a
much, much slower pace.

> Also, I believe CHICKEN's exit procedures are still not technically
> R7RS-compliant even given these changes, since a user-specified
> `exit-handler` or `on-exit` procedure may signal an error, contain a
> non-local escape or simply refuse to exit, all of which are verboten by
> the draft. I think this is probably OK, but others may feel differently.

I don't have the draft here right now, but I guess it just means it's
undefined what will happen, meaning CHICKEN's behaviour is allowed as
an "extension".  Portable code shouldn't rely on it, but it's fine if
an implementation adds meaning to something that's undefined.

Cheers,
Peter
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