#! perl -l
use strict;
use warnings;

sub test{
    our $test{localsub} = sub{
        print 'localsub1';
        return 12345;
    } unless exists $test{localsub};

    $test{localsub}->();
}

print test;
__END__
P:\test>junk
syntax error at P:\test\junk.pl line 6, near "$test{localsub"
Execution of P:\test\junk.pl aborted due to compilation errors.