http://www.perlmonks.org?node_id=977476


in reply to Re^2: symboltable problem
in thread symboltable problem

I think the problem is that %Bubba:: = %Hubba:: is creating a new hash, which destroys the binding of $Bubba::abba to the original hash set up at compile time of the latter expression.  This reasoning is based on the observation that both of the following work fine: 

#!/usr/bin/perl
use strict;

$Hubba::abba = "zappa\n";

%Bubba:: = %Hubba::;

# compile time deferred
eval 'print $Bubba::abba';

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#!/usr/bin/perl
use strict;

$Hubba::abba = "zappa\n";

# copying via hash slice doesn't create new hash
@Bubba::{keys %Hubba::} = @Hubba::{keys %Hubba::};
# or: @Bubba::{keys %Hubba::} = values %Hubba::;

print $Bubba::abba;

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Re^4: symboltable problem
by choroba (Cardinal) on Jun 20, 2012 at 21:55 UTC
    Yes, that seems to eplain it. Another solution then is to create the alias in a BEGIN block.
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Re^4: symboltable problem
by morgon (Priest) on Jun 21, 2012 at 16:00 UTC
    Thanks - that is very interesting. I did not expect that...

    I find this illustration quite amusing: 

    use strict;

our $foo = "old value\n";
%:: = (%::);

our $var = "new value\n";
$::{foo} = *var;

print $foo;
eval q| print $foo |;

    [download]
    btw: Is there a nicer way to create a typeglob with a given value in the scalar-slot?
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