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Issue: UNWIND-PROTECT-CLEANUP-NON-LOCAL-EXIT (Version 2)
- To: Masinter.firstname.lastname@example.org
- Subject: Issue: UNWIND-PROTECT-CLEANUP-NON-LOCAL-EXIT (Version 2)
- From: gls@Think.COM
- Date: Mon, 26 Oct 87 13:49:43 EST
- Cc: email@example.com, Hornig@scrc.symbolics.com, Masinter.firstname.lastname@example.org
- In-reply-to: Masinter.email@example.com's message of 24 Oct 87 17:30 PDT <871024-173113-2262@Xerox>
I will reiterate my support for 1-RETURN-INNER (as well as 2-EXIT).
We have here a classic case of the irresistible force (QUIT, dammit!)
versus the immovable mountain (UNWIND-PROTECT). I find that the
suggestion that situation 1 produce an error, but one that IGNORE-ERRORS
won't ignore, to be at least one level of epicycle too many.
Which mechanism are to we regard as primitive: the error system or the
catch/throw system? Or are they disjoint? I prefer, for simplicity, a
model in which the error system can be explained. as much as possible, as a
complex thing built on top of catch, throw, and unwind-protect.