* unwind-protect for lexical binding
@ 2014-03-11 3:42 Sergey Mozgovoy
2014-03-11 17:21 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: Sergey Mozgovoy @ 2014-03-11 3:42 UTC (permalink / raw)
To: Emacs-devel
I propose a patch for Emacs 24.3 that implements a new byte code for
unwind-protect which is more friendly for lexical scope.
100 lex-unwind-protect <address> ------o
103 {protection body} |
... ................. |
176 byte-return |
177 {protected-form} <------------------o
... ..................
217 byte-unbind 1
... ..................
This works as shown above: execution of `unwind-protect' starts with
retaining where the protection body is and jumping to the protected
form. When unwinding, the remembered element is popped off the
specpdl stack, and a call into the necessary spot inside the bytecode
string is made.
I'll be very thankful to see any comments and thoughts on this idea.
Unfortunately, for this aproach to work I had to disable some
byte-level optimizations in `byte-opt.el' -- namely, the
`byte-after-unbind-ops' variable and the corresponding trick which
moves some bytecodes past an `unbind'.
Here's a list of patched files:
alloc.c.diff <http://emacs.1067599.n5.nabble.com/file/n316523/alloc.c.diff>
bytecode.c.diff
<http://emacs.1067599.n5.nabble.com/file/n316523/bytecode.c.diff>
lisp.h.diff <http://emacs.1067599.n5.nabble.com/file/n316523/lisp.h.diff>
bytecomp.el.diff
<http://emacs.1067599.n5.nabble.com/file/n316523/bytecomp.el.diff>
byte-opt.el.diff
<http://emacs.1067599.n5.nabble.com/file/n316523/byte-opt.el.diff>
cconv.el.diff
<http://emacs.1067599.n5.nabble.com/file/n316523/cconv.el.diff>
---
Best regards,
Sergey Mozgovoy.
--
View this message in context: http://emacs.1067599.n5.nabble.com/unwind-protect-for-lexical-binding-tp316523.html
Sent from the Emacs - Dev mailing list archive at Nabble.com.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: unwind-protect for lexical binding
2014-03-11 3:42 unwind-protect for lexical binding Sergey Mozgovoy
@ 2014-03-11 17:21 ` Stefan Monnier
2014-03-11 20:09 ` Sergey Mozgovoy
0 siblings, 1 reply; 4+ messages in thread
From: Stefan Monnier @ 2014-03-11 17:21 UTC (permalink / raw)
To: Sergey Mozgovoy; +Cc: Emacs-devel
> I propose a patch for Emacs 24.3 that implements a new byte code for
> unwind-protect which is more friendly for lexical scope.
> 100 lex-unwind-protect <address> ------o
> 103 {protection body} |
> ... ................. |
> 176 byte-return |
> 177 {protected-form} <------------------o
> ... ..................
> 217 byte-unbind 1
> ... ..................
Have you looked at the trunk version of bytecode.c ?
I added some byte-codes for the same problem a few months ago (to make
the byte-compiler use them, set byte-compile--use-old-handlers to nil).
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: unwind-protect for lexical binding
2014-03-11 17:21 ` Stefan Monnier
@ 2014-03-11 20:09 ` Sergey Mozgovoy
2014-03-12 13:20 ` Stefan Monnier
0 siblings, 1 reply; 4+ messages in thread
From: Sergey Mozgovoy @ 2014-03-11 20:09 UTC (permalink / raw)
To: Emacs-devel
Stefan Monnier wrote
> Have you looked at the trunk version of bytecode.c ?
No, I haven't. I implemented this thing about a half a year ago,
and this is the first time I tried to make it public. Seems to
be too late :)
--
View this message in context: http://emacs.1067599.n5.nabble.com/unwind-protect-for-lexical-binding-tp316523p316572.html
Sent from the Emacs - Dev mailing list archive at Nabble.com.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: unwind-protect for lexical binding
2014-03-11 20:09 ` Sergey Mozgovoy
@ 2014-03-12 13:20 ` Stefan Monnier
0 siblings, 0 replies; 4+ messages in thread
From: Stefan Monnier @ 2014-03-12 13:20 UTC (permalink / raw)
To: Sergey Mozgovoy; +Cc: Emacs-devel
>> Have you looked at the trunk version of bytecode.c ?
> No, I haven't. I implemented this thing about a half a year ago,
> and this is the first time I tried to make it public. Seems to
> be too late :)
Well, the new opcodes are pretty much unused so far (since the default
for byte-compile--use-old-handlers is t) and 24.4 is not yet released,
so if you find some problem with the new opcodes, it's not too late.
Stefan
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-03-12 13:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-03-11 3:42 unwind-protect for lexical binding Sergey Mozgovoy
2014-03-11 17:21 ` Stefan Monnier
2014-03-11 20:09 ` Sergey Mozgovoy
2014-03-12 13:20 ` Stefan Monnier
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/emacs.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).