dsheroh has asked for the wisdom of the Perl Monks concerning the following question:

Continuing on from my earlier question, "use"ing from dynamic namespace, I've found myself needlessly repeating things like 
use Base::Module;
Base::Module::Config->import(qw( %conf ));

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every time I used this code. So, naturally, I thought, I'd just re-export those from the core: 
package Base::Module;

use strict;
use warnings;

sub config_module { "Base::Module::Config" }

use base 'Exporter';
BEGIN {
  our @EXPORT_OK = qw( &%conf );

  eval 'require ' . config_module;

  no strict 'refs';
  no warnings 'once';

  *conf = \%{config_module . '::conf'};
}

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This comes deceptively close to working, but I'm seeing some users of Base::Module getting one %conf and others getting a different %conf. I suspect that it's related to whether they import it using 
use Base::Module qw( %conf );

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or 
sub base_module { "Base::Module" }

BEGIN {
  eval 'require ' . base_module;
  base_module()->import(qw( %conf ));
}

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but I'm not positive. It could also be the distinction between being used in the final program (first form) vs. being used by other modules which are a part of this structure (second form).

In any case, what would be the correct (or at least a fully-working) way to accomplish this?

Replies are listed 'Best First'.
Re: Re-exporting dynamically-included variables
by tilly (Archbishop) on Jan 09, 2009 at 23:51 UTC
    This should work. 
    package Base::Module;
use strict;
use warnings;

use Base::Module::Config qw(%conf);
use Exporter qw(import);
our @EXPORT_OK = qw(%conf);
# ...
1;

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[reply]
[d/l]
      That would be the obvious solution if the namespace were static, but (as explained more extensively in "use"ing from dynamic namespace) the idea here is that I want to be able to derive a Foo::Module and a Bar::Module from Base::Module which reference Foo::Module::Config and Bar::Module::Config (respectively) instead of Base::Module::Config (since the Foo and Bar applications would, naturally, each want their own configurations).
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[d/l]
[select]
        My attitude is that that is exactly the sort of situation that eval exists for. Just be sure to check for $@ and die if you've trapped a real error.
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