Greetings.

Quick background: I want to use a module if it exists, otherwise use another, then create a file-scoped lexical object of the appropriate class. This would best be done in a BEGIN block, I've figured out.

After a few Super Searches, I figured out a few ways to set a file-scoped variable within said BEGIN block, and I'm wondering which is the Best Way, or if it's just a matter of programmer preference.

I have all methods incorporated in the code snippet below, so I wouldn't have to illustrate things four times. They all work, except for the $our_var method. I find this odd, since a "use vars" variable works, but "our" doesn't. Aren't the two the same thing?

Thanks to tye and this node for pointing out that a 'my' var declared before a BEGIN block won't cause problems. I assumed that it wouldn't work, but it does. Yay.

Anyway, here's my code: 

 
use strict;
my $pre;
BEGIN {
  my $closure;
  our $our_var;
  use vars qw/$vars/;

  if (eval {require CGI::Safe} ) { 
    CGI::Safe->import();
    $closure = CGI::Safe->new;
    $vars = CGI::Safe->new;
    $pre = CGI::Safe->new;
    $our_var = CGI::Safe->new;
  } else { 
    $< = $>;
    delete @ENV{qw(IFS CDPATH ENV BASH_ENV SHELL PATH)};
    require CGI;
    CGI->import( qw/ :standard / );
    $CGI::DISABLE_UPLOADS = 1;
    $CGI::POST_MAX        = 512 * 1024; 
    $closure=CGI->new; 
    $vars=CGI->new; 
    $pre=CGI->new; 
    $our_var=CGI->new; 
  }
  sub get_obj { return $closure };
}

my $q = get_obj();
printf "object in 'closure' method is of class %s\n", ref ($q);
printf "object in 'usr vars' method is of class %s\n", ref ($vars);
printf "object in 'my' method is of class %s\n", ref ($pre);
#printf "object in 'our' method is of class %s\n", ref ($our_var);

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So, which is best? Is that even a real closure? And why doesn't the $our_var method work? Thanks for any help, folks.

Mephit

--

There are 10 kinds of people -- those that understand binary, and those that don't.

In reply to Setting lexicals in a BEGIN block. by mephit

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