From: Gregory Heytings <gregory@heytings.org>
To: "Mattias Engdegård" <mattiase@acm.org>
Cc: 47677@debbugs.gnu.org
Subject: bug#47677: [PATCH] condition-case success continuation
Date: Mon, 26 Apr 2021 21:57:46 +0000 [thread overview]
Message-ID: <770e344122f2eed113c2@heytings.org> (raw)
In-Reply-To: <219007D9-0FD0-4AC2-A8B0-24A0FC277AE8@acm.org>
>
> This patch adds the condition-case handler syntax
>
> (:success BODY)
>
> for code executed when the protected form terminates without error. BODY
> is then executed with the variable bound to the result of the protected
> form, and the result of BODY is then the value of the condition-case
> form as usual.
>
> This plugs an annoying hole in elisp: there hasn't been any direct
> access to the success continuation
>
Would a macro not be enough to cover that particular programming pattern?
E.g. something like:
(defmacro success-case (value action continuation &rest handlers)
`(catch 'success-case-fail
((lambda (,value) ,continuation)
(catch 'success-case-success
(throw 'success-case-fail
(condition-case ,value
(throw 'success-case-success ,action) ,@handlers))))))
With this macro you can write for example:
(success-case result
(read buffer)
(use result)
(end-of-file 'eof))
which is IMO even more concise and elegant.
prev parent reply other threads:[~2021-04-26 21:57 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-09 20:26 bug#47677: [PATCH] condition-case success continuation Mattias Engdegård
2021-04-10 23:52 ` Stefan Monnier
2021-04-11 11:13 ` Mattias Engdegård
2021-04-12 8:49 ` Lars Ingebrigtsen
2021-04-12 15:10 ` Stefan Monnier
2021-04-12 19:20 ` Mattias Engdegård
2021-04-13 7:38 ` Lars Ingebrigtsen
2021-04-13 8:52 ` Mattias Engdegård
2021-04-14 9:29 ` Lars Ingebrigtsen
2021-04-15 13:54 ` Mattias Engdegård
2021-04-16 5:13 ` Richard Stallman
2021-04-16 5:13 ` Richard Stallman
2021-04-21 14:13 ` Stefan Kangas
2021-04-22 13:58 ` Mattias Engdegård
2021-04-23 4:18 ` Richard Stallman
2021-04-24 17:02 ` Mattias Engdegård
2021-04-25 4:44 ` Richard Stallman
2021-04-25 7:35 ` Eli Zaretskii
2021-04-25 18:21 ` bug#47677: [External] : " Drew Adams
2021-04-25 18:24 ` Eli Zaretskii
2021-04-26 4:40 ` Richard Stallman
2021-04-26 12:44 ` Eli Zaretskii
2021-04-27 3:46 ` Richard Stallman
2021-04-26 15:12 ` Filipp Gunbin
2021-04-27 15:31 ` Mattias Engdegård
2021-04-27 19:00 ` Gregory Heytings
2021-04-29 12:45 ` Filipp Gunbin
2021-04-25 16:45 ` Lars Ingebrigtsen
2021-04-26 11:53 ` Mattias Engdegård
2021-04-27 3:46 ` Richard Stallman
2021-04-26 21:57 ` Gregory Heytings [this message]
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