From: Chong Yidong <cyd@stupidchicken.com>
To: Miles Bader <miles@gnu.org>
Cc: emacs-devel@gnu.org
Subject: Re: return
Date: Fri, 03 Dec 2010 17:44:01 -0500 [thread overview]
Message-ID: <87vd3a79zi.fsf@stupidchicken.com> (raw)
In-Reply-To: <87ei9y5z0v.fsf@stupidchicken.com> (Chong Yidong's message of "Fri, 03 Dec 2010 16:26:08 -0500")
Chong Yidong <cyd@stupidchicken.com> writes:
> This (very limited) test indicates that adding built-in support for
> block, return, and return-from should have little performance impact.
> (Though the block tags ought to use a specialized obarray instead of
> what cl-macs.el does, which is to intern them as "--cl-block-%s--".)
>
> Does anyone see a deeper problem with providing such functions?
Thinking about this some more, I do see a couple of snags. First, the
`dotimes' and `dolist' macros use `while' internally, so if we introduce
a built-in `return' that exits from `while', it's hard to make that same
`return' exit correctly from `dotimes'/`dolist'. One solution might be
to introduce something like `while-noblock' and use that in `dotimes'
and `dolist'.
Also, block tags should have lexical scope, so in order to implement
`block' properly we probably ought to wait for the lexical binding
changes. I think it is currently possible to implement `return' for
exiting unnamed blocks, and leave `block'/`return-from' for the future,
but I dunno if doing it like that is worth our while.
next prev parent reply other threads:[~2010-12-03 22:44 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-26 8:57 return Lars Magne Ingebrigtsen
2010-11-26 9:19 ` return Tassilo Horn
2010-12-04 2:36 ` return Fren Zeee
2010-12-04 3:04 ` Common vs Emacs Lisp (was: Re: return) Chad Brown
2010-12-04 19:48 ` Fren Zeee
2010-12-05 10:20 ` Chad Brown
2010-12-04 6:18 ` return Stephen J. Turnbull
2010-12-04 6:49 ` return Leo
2010-11-26 9:24 ` return Miles Bader
2010-11-26 9:36 ` return Lars Magne Ingebrigtsen
2010-11-26 9:54 ` return Miles Bader
2010-11-26 10:13 ` return Lars Magne Ingebrigtsen
2010-11-26 9:44 ` return Tassilo Horn
2010-11-26 14:59 ` return Stefan Monnier
2010-11-26 15:45 ` return Lars Magne Ingebrigtsen
2010-11-26 18:40 ` return Stefan Monnier
2010-11-27 1:31 ` return Lars Magne Ingebrigtsen
2010-11-27 2:49 ` return Stefan Monnier
2010-11-27 3:06 ` return Lars Magne Ingebrigtsen
2010-12-03 18:41 ` return Chong Yidong
2010-12-03 18:43 ` return Miles Bader
2010-12-03 19:46 ` return Chong Yidong
2010-12-03 21:26 ` return Chong Yidong
2010-12-03 22:29 ` return Stefan Monnier
2010-12-03 23:00 ` return Chong Yidong
2010-12-04 1:35 ` return Stefan Monnier
2010-12-04 3:23 ` return Chong Yidong
2010-12-06 16:13 ` return Davis Herring
2010-12-06 17:15 ` return Chong Yidong
2010-12-03 22:44 ` Chong Yidong [this message]
2010-12-04 9:22 ` return Helmut Eller
-- strict thread matches above, loose matches on Subject: below --
2010-11-26 23:01 return MON KEY
2010-12-05 23:55 Return MON KEY
2010-12-06 1:48 ` Return Stephen J. Turnbull
2010-12-06 5:50 ` Return MON KEY
2010-12-06 7:20 ` Return Stephen J. Turnbull
2010-12-06 9:00 ` Return David Kastrup
2010-12-06 19:11 ` Return Stefan Monnier
2010-12-06 19:09 ` Return Stefan Monnier
2010-12-06 19:19 ` Return Chong Yidong
2010-12-06 20:27 ` Return Stefan Monnier
2010-12-07 4:47 ` Return Miles Bader
2010-12-07 9:17 ` Return David Kastrup
2010-12-07 17:10 ` Return Stefan Monnier
2010-12-07 22:15 ` Return David Kastrup
2010-12-08 15:50 ` Return Fren Zeee
2010-12-09 22:38 ` Return Stefan Monnier
2010-12-10 1:41 ` Return Stephen J. Turnbull
2010-12-10 3:44 ` Return Stefan Monnier
2010-12-10 8:28 ` Return Stephen J. Turnbull
2010-12-23 5:39 ` Return Fren Zeee
2010-12-07 12:44 ` Return Stephen J. Turnbull
2010-12-07 14:38 ` Return David Kastrup
2010-12-07 16:14 ` Return Stephen J. Turnbull
2010-12-07 17:11 ` Return tomas
2010-12-07 2:42 ` Return MON KEY
2010-12-07 14:34 ` Return Stephen J. Turnbull
2010-12-07 15:54 ` Return David Kastrup
2010-12-07 16:30 ` Return Stephen J. Turnbull
2010-12-08 13:42 ` Return Richard Stallman
2010-12-10 7:42 ` Return Daniel Colascione
2010-12-07 22:55 ` Return MON KEY
2010-12-08 7:28 ` Return Stephen J. Turnbull
2010-12-08 18:11 ` Return MON KEY
2010-12-09 8:37 ` Return Stephen J. Turnbull
2010-12-07 23:21 ` Return Samuel Bronson
2010-12-08 8:06 ` Return Stephen J. Turnbull
2010-12-08 20:51 ` Return Samuel Bronson
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