# So, how to get $Foo::Str without soft ref?

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Moreover, how to know whether an arbitrary package has a specific global

1. various ways.
a) Any symbol table your current symbol table knows about - is in the current symbol table. So: 

use strict;
package Foo;

use vars qw($str); # $Foo::str created
$str = 'foo str';

package main;

my $pack = "Foo::";
my $var = "str";
print ${*{${$main::{$pack}}{$var}}{SCALAR}};
__END__
foo str

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b) You could also use string eval - but that's as deprecated as symbolic references hereabouts ;-) 

use strict;
$Foo::str = 'foo str';
my $class = 'Foo';
my $value = eval "\$$class\::str";
print $value,$/;

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2. Look into the symbol table:

package Foo;

use vars qw($str);
$str = "foo str";

package main; 

my $pack = "Foo::";
my $var = "str";
print "$_: ",(defined ${$main::{$pack}}{$_} ? 'yup' : 'nope'),$/
    for qw(str bar);
__END__
str: yup
bar: nope

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update: Caveats about autovivification apply. You might want to break up the lookup into steps, operating with defined. Consider:

$\=$/;
use strict;
use warnings;

package Foo;

use vars qw($str);
$str = "foo str";

package main;

my $pack = "Bar::";
my $var = "str";
print "yup" if defined ${$main::{$pack}}{$var};
/::$/ and print for keys %main::
__END__
version::
Tie::
utf8::
re::
CORE::
DynaLoader::
mro::
strict::
attributes::
Bar::       <----here
Regexp::
vars::
UNIVERSAL::
Foo::
main::
Carp::
PerlIO::
IO::
Internals::
warnings::
DB::

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Symbol tables are subject to autovivification, too.

In reply to Re: How to access globals in arbitrary classes, without using soft ref? by shmem
in thread How to access globals in arbitrary classes, without using soft ref? by llancet

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