tieing stashes #6983
Comments
From tassilo.parseval@post.rwth-aachen.deCreated by tassilo.parseval@post.rwth-aachen.deI noticed that perl wont stop you from tieing a stash: ethan@ethan:~$ perl5.8.2 -MTie::Hash -MPOSIX=_exit -e 'tie %:: => "Tie::StdHash"; _exit(1)' When a proper shutdown via END happens, a seemingly unrelated message appears: ethan@ethan:~$ perl5.8.2 -MTie::Hash -e 'tie %:: => "Tie::StdHash"' Should these ties make perl croak when they happen? I can't yet see what Also not bad: ethan@ethan:~$ perl5.8.2 -MTie::Hash Tassilo Perl Info |
From tassilo.parseval@post.rwth-aachen.deOn Fri, Dec 12, 2003 at 07:50:04PM +0000 Tassilo v.Parseval (via RT) wrote:
[...]
[...] Well, in case croaking turns out to be an acceptable solution, the Tassilo PS: Should patch-submitters also modify perldelta.pod accordingly or |
From tassilo.parseval@post.rwth-aachen.deInline Patch--- pp_sys.c~ 2003-10-21 09:01:45.000000000 +0200
+++ pp_sys.c 2003-12-13 09:09:26.000000000 +0100
@@ -787,6 +787,8 @@ PP(pp_tie)
varsv = *++MARK;
switch(SvTYPE(varsv)) {
case SVt_PVHV:
+ if (HvNAME((HV*)varsv))
+ Perl_croak(aTHX_ "Can't tie symbol table of package '%s'", HvNAME((HV*)varsv));
methname = "TIEHASH";
HvEITER((HV *)varsv) = Null(HE *);
break;
--- pod/perldiag.pod~ 2003-12-12 01:02:52.000000000 +0100
+++ pod/perldiag.pod 2003-12-13 09:09:36.000000000 +0100
@@ -1004,6 +1004,12 @@ negative numbers.
negative number. There's a Math::Complex package that comes standard
with Perl, though, if you really want to do that.
+=item Can't tie symbol table of package '%s'
+
+(F) You tried to tie the symbol table of the mentioned package.
+Your script would stop working very soon if perl allowed such an
+operation.
+
=item Can't undef active subroutine
(F) You can't undefine a routine that's currently running. You can, |
From @rgsTassilo von Parseval wrote:
It seems to be good idea, to prevent doing strange things with stashes. (PS - perldelta.pod patches are traditionally not considered necessary.) |
From tassilo.parseval@post.rwth-aachen.deOn Sat, Dec 13, 2003 at 09:58:51AM +0100 Rafael Garcia-Suarez wrote:
The whole stash or just the keys? When I use the lock_hash() routine ethan@ethan:~$ perl5.8.2 -MHash::Util=lock_hash At run-time: Making stashes read-only (or alternatively make the core ignore Tassilo |
From enache@rdslink.roOn Sat, Dec 13, 2003 a.d., Rafael Garcia-Suarez wrote:
Is the only benefit of this preventing bold and/or naive users from doing Regards, |
From @rgsEnache Adrian wrote:
Replace strange by broken if you want. Marking stashes readonly, OTOH, |
From tassilo.parseval@post.rwth-aachen.deOn Sat, Dec 13, 2003 at 12:44:16PM +0000 Adrian Enache via RT wrote:
This goes beyond strange. No matter how hard I try, I can't make a tied The second route seems to be the easier one. As for read-onliness: I don't quite understand how this is going to Tassilo |
From @rgsTassilo von Parseval wrote:
I'd like to understand what kind of scalar cuoldn't be upgraded.
As symbols are stored in stashes like values in regular hashes, I don't |
From enache@rdslink.roOn Sat, Dec 13, 2003 a.d., Tassilo von Parseval wrote:
That message is there since the the tied hash elems were changed to LVs. Regards, |
From tassilo.parseval@post.rwth-aachen.deOn Sat, Dec 13, 2003 at 01:44:17PM +0000 Rafael Garcia-Suarez via RT wrote:
Hmmh, this one: SV = PVLV(0x818c830) at 0x8149a68 I don't understand where it comes from.
The stash can be changed during the runtime of a script. This will then eval 'sub bla { ... }'; So anything that adds something to the hash at runtime (most AUTOLOADers Tassilo |
From @iabynOn Sat, Dec 13, 2003 at 04:56:27PM +0100, Tassilo von Parseval wrote:
That's the tempoary proxy SV used when accessing tied aggregrates (arrays svp = av_fetch(av,3,lval=>1); the only way to make tie work in this environment is for av_fetch() to -- |
From @scottwaltersEnough rope to let typesafety.pm do method overloading on -scott On 0, Rafael Garcia-Suarez <rgarciasuarez@free.fr> wrote:
|
From nick@ing-simmons.netTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
As the readonly stuff is much closer to the guts of HVs than tie
Seems reasonable message.
Less so.
|
From nick@ing-simmons.netTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
I can imagine marking at least a sub-stash as READONLY at (say) CHECK
|
From tassilo.parseval@post.rwth-aachen.deOn Sat, Dec 13, 2003 at 07:06:11PM +0000 Dave Mitchell wrote:
Thanks for the explanation. I didn't know any of the above yet. I still Furthermore, we should try to come to a conclusion as to what should Tassilo |
From @lizmatAt 21:02 +0000 12/13/03, Nick Ing-Simmons wrote:
How would that work with e.g. mod_perl? When CHECK and INIT have This is less an issue with read-onlyness (which I like by itself) and Liz |
From nick@ing-simmons.netElizabeth Mattijsen <liz@dijkmat.nl> writes:
It wouldn't - but as you note this is an issue with CHECK rather
|
From @ysthOn Sat, Dec 13, 2003 at 07:06:11PM +0000, Dave Mitchell <davem@fdgroup.com> wrote:
Not good. You can't store a fake glob in a tied hash anymore: $ perl -we'use Tie::Hash; tie %h, "Tie::StdHash"; $h{foo} = *STDOUT; use Devel: |
From rick@bort.caOn Sat, Dec 13, 2003 at 04:17:06PM +0200, Enache Adrian wrote:
Aside from tuits, is there any reason why this couldn't be done now? http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2001-11/msg00203.html which provides an alternative to tie. It doesn't support all the ops -- |
From tassilo.parseval@post.rwth-aachen.deOn Sun, Dec 14, 2003 at 11:27:38PM -0500 Rick Delaney wrote:
This sounds a little like old wine in new containers. As I see it, the What I'd like to see (for tied hashes) is this: EXT MGVTBL_EXTENDED PL_vtbl_tiedhash = { This would also solve the problem of implementing a tied hash in XS Right now this is impossible because the majority of the tied If we are really considering to reimplement the innards of tied hashes Tassilo |
From @lizmatAt 08:28 +0100 12/15/03, Tassilo von Parseval wrote:
What you describe here, is called "Ponie" to a large extent (the way Liz |
From tassilo.parseval@post.rwth-aachen.deOn Mon, Dec 15, 2003 at 08:40:22AM +0100 Elizabeth Mattijsen wrote:
I hope this isn't used as an argument against extending the virtual Just for fun, I am right now adding MGVTBLX to the core. That's going to Tassilo |
From @lizmatAt 09:26 +0100 12/15/03, Tassilo von Parseval wrote:
Yes and no. One the one hand, I wouldn't dream about telling anybody On the other hand, when Ponie comes around, your work may not be Personally, I always try to find solace in the fact that with any Liz |
From @hvdsRafael Garcia-Suarez <rgarciasuarez@free.fr> wrote: I agree: attempting to tie a stash should croak at least until we can Hugo |
From rick@bort.caOn Mon, Dec 15, 2003 at 08:28:23AM +0100, Tassilo von Parseval wrote:
I don't think I suggested Doug's patch would solve any of the recently Anyway, as I see it the bigger problem with tie is not the current
Sure, whatever. I'll ask again:
I ask because I don't know enough about this area of the internals to know -- |
From nick.ing-simmons@elixent.comRick Delaney <rick@bort.ca> writes:
It _is_ being done now. This kind of tidy up is exactly what perl6 is about. Re-doing tie in perl5 another way is I suppose possible, but perl5 needs |
From @iabynOn Sun, Dec 14, 2003 at 01:28:22PM -0800, Yitzchak Scott-Thoennes wrote:
You can get a similar effect without tiedness (but with lvalues): $ perl5.8.0 -wle 'sub f { $_[0] = *STDOUT } my %h; f($h{a})' So should lvlaues be fixed in some way, or was it plain wrong to use LVs -- |
From tassilo.parseval@post.rwth-aachen.deOn Mon, Dec 15, 2003 at 10:31:13AM +0000 hv@crypt.org wrote:
So far all my attempts in finding out how a read-only stash could sub AUTOLOAD { ? Aren't those additions to the stash happening at run-time? Tassilo |
From tassilo.parseval@post.rwth-aachen.deOn Mon, Dec 15, 2003 at 05:51:19PM +0000 Nick Ing-Simmons wrote:
I think a new implementation would only expose those code to All the above however leads us astray. I don't think it's very likely Tassilo |
From @lizmatAt 22:24 +0100 12/15/03, Tassilo von Parseval wrote:
Indeed. That's something you can't do then. The same would Liz |
From @scottwaltersLet me be more clear - if you nice folks make stashes tieable with Again, I've wanted that feature for a while (as do a lot of people) Cheers! On 0, Elizabeth Mattijsen <liz@dijkmat.nl> wrote:
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From nick.ing-simmons@elixent.comTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
Well you can count me as arguing that way. Existing XS modules which MGVTBL TkGlue_vtab = { ... } and similar - those need to continue to work.
I quick grep of perltie.pod shows 25 method names not counting =item CLEAR this
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From nick.ing-simmons@elixent.comTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
Yes. That is just the kind of thing a readonly stash could be used
|
From nick.ing-simmons@elixent.comTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
It isn't rare - my guess is that most XS modules that use MAGIC
Which are the ones that XS uses and '~' magic in particular
|
From tassilo.parseval@post.rwth-aachen.deOn Tue, Dec 16, 2003 at 04:22:11PM +0000 Nick Ing-Simmons wrote:
As long as they are not of type PERL_MAGIC_tied, they should. :-) To make it fully backwards-compatible (even with tied variables), it PERL_MAGIC_tied would remain what it is now for those extension that
Oups, forgot FIRSTKEY and NEXTKEY. Not a big deal since so far The other ones that are missing are all methods of a tied handle since I Tassilo |
From tassilo.parseval@post.rwth-aachen.deOn Tue, Dec 16, 2003 at 04:38:24PM +0000 Nick Ing-Simmons wrote:
I don't think we want to disallow anything that works perfectly well. The read-onlyness can already be done now, namely by turning a stash Tassilo |
From @lizmatAt 18:06 +0100 12/16/03, Tassilo von Parseval wrote:
But, as I already tried to point out, CHECK is pretty useless for that. Suppose I'm an author of a CPAN module who wants to make sure that Liz |
From nick.ing-simmons@elixent.comTassilo Parseval <tassilo.parseval@post.rwth-aachen.de> writes:
What I meant is that the MAIN use I can see for a readonly stash is
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@rspier - Status changed from 'new' to 'open' |
From @doyThe examples given in the original post no longer cause that warning, BEGIN { -doy |
From @rurbanOn Thu, Jul 5, 2012 at 3:03 PM, Jesse Luehrs via RT
1. To tie a stash should either fail (best compile-time), or we need 2. The whole readonly-stash discussion in 2003 was a bit odd. There is just no sanctioned syntax for it. Damian thought of |
From @LeontOn Sun, Jul 8, 2012 at 7:35 PM, Reini Urban <rurban@x-ray.at> wrote:
Right now we don't even have proper read-only hashes IMHO. The Leon |
Migrated from rt.perl.org#24652 (status was 'open')
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