Question

After studying the Perl require docs and other links like this on Stackoverflow I’m still none the wiser, must be missing a fairly simple trick. I’m loading a module at runtime and calling a subroutine in it. The problem is I don’t necessarily know the name of the exported subroutine, but there must be one and it is exported.

The modules all look like this, ie. they roughly follow a template taken from perlmonks.org

package modules::Test;

use strict;
use Exporter;
use vars qw($VERSION @ISA @EXPORT @EXPORT_OK %EXPORT_TAGS);

$VERSION     = 1.00;
@ISA         = qw(Exporter);
@EXPORT      = (*TestSubSomeUnknownName);
@EXPORT_OK   = qw(&TestSubSomeUnknownName);
%EXPORT_TAGS = ( ALL => [qw(&TestSubSomeUnknownName)]
               );


sub TestSubSomeUnknownName
{
    # return a hash reference
}

Then I can access the sub like this, assuming I know its name:

use Module::Load;

my $package = "modules::Test";
my $subr = "TestSubSomeUnknownName";

load $package;
# Call the subroutine
my $hashref = $package->$subr;

But what if someone mis-spelled the name in a package or I don’t know it? The solution seems to be to use one of the EXPORTs to see what’s in there, but how can it be done?

Answer 1

• @EXPORT should contain names not symbols.
• You don’t need the ampersand before the function name and it’s non standard.
• Remember the to return 1 at the end of a module.

• If you want to check what a package can do, use can.

  die 'Auto-import sub was not named "TestSubSomeUnknownName"' 
      unless  $package->can( 'TestSubSomeUnknownName' )
      ;
  $package->TestSubSomeUnknownName();