Beefy Boxes and Bandwidth Generously Provided by pair Networks
"be consistent"
 
PerlMonks  

Re^2: Mixing tied variables with goto label

by Limbic~Region (Chancellor)
on Nov 16, 2005 at 00:50 UTC ( #508858=note: print w/replies, xml ) Need Help??


in reply to Re: Mixing tied variables with goto label
in thread Mixing tied variables with goto label

dave_the_m,
I couldn't find it documented anywhere. So it is how the function is called that is causing the problem. I can still produce a fair amount of misdirection. I am not sure I have the time or energy to actually make the obfu, but I would be happy and impressed if someone did. Like most magic and misdirection, the most important part is the setup.

You will need to hide the tie, sub TIESCALAR, and friends. This should be possible using evil eval. The FETCH needs to be special too. Instead of using an internal goto to produce the magic, it will return the current value in the STORE the first time, but the second time it will return a different label.

my $label; # magic setup happens here $label = 'START'; print "$label\n"; # prints START goto $label; exit; START: print "Hello, world\n"; END: print "Goodbye, cruel world\n";
When it is run, the output will be unexpected:
START Goodbye, cruel world
In any case, if you happen to find some documentation explaining this behavior I would appreciate it.

Cheers - L~R

Log In?
Username:
Password:

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://508858]
help
Chatterbox?
[Discipulus]: i'v installed ubuntu 16.04lts and i'm quite disappointed: is deadly simmilar to new win osses where you cannot find even simple things...
[Corion]: Hi Discipulus ;)
[Corion]: Mj1234: Maybe Ubuntu didn't package Devel::GDB? In that case, consider using local::lib and install the module from CPAN
[Corion]: But a quick Google search turns up this page, which seems to suggest that it should be packaged
[Discipulus]: iirc active perl has repositories only for last 2 o 3 major release of perl Mj1234. I strongly suggest portable version of strawberry perl and use cpan client to install modules
[choroba]: Also, who needs GDB when there's hdb?
[Discipulus]: in this ubuntu i'm not able to find resource monitor, graphical mount program.. just office and amazon are exposed!

How do I use this? | Other CB clients
Other Users?
Others imbibing at the Monastery: (7)
As of 2016-12-07 08:57 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    On a regular basis, I'm most likely to spy upon:













    Results (125 votes). Check out past polls.