Variable scope in packages.

[CuriousGeorge]

Hi all. Say I have a script Foo.pl that has a hash %crap. Now I define a package called BooYah.pm. If I do a require "Foo.pl" in BooYah, how can I access %crap? Thanks for all the help!

[damian1301]

When you require a script(*.pl), it brings it's variables, subs, and all into your namespace so you can simply access it as %crap. Voila!

NOTE: That if you require a package it will not be the same. It will not be automatically included in your namespace and you would have to make each call explicitly -- Credit goes to Petruchio on the note.



$_.=($=+(6<<1));print(chr(my$a=$_));$^H=$_+$_;$_=$^H;
print chr($_-39); # Easy but its ok.

[runrig]

Note: if you are using strict (in BooYah.pm), and %crap is declared with my in Foo.pl, then you won't be able to access it at all. Heck, you won't even be able to run the program (if you try to access it from BooYah.pm that is) :)

[cLive ;-)]

BooYah.pm is only a package if you begin it with:

package BooYah;

Then, all vars in that package can be accessed as $BooYah::var_name.

Of course, you can have more than one package in a script :)

I think what you're asking is "what is the default package?". The answer to that is 'main' or '' by default.

The var would have to be declared globally (no my/local) and explicitly (you are using strict now, aren't you :). BUT, it's a bad idea to rely on vars in main from the package that was required. If you do though, there are two instances I can think of:

# (1)

# Foo.pl - extract
# implicitly
%::crap = (turd => 'yellowy brown',
           crap => 'browny black');

# or explicitly
%main::crap = (turd => 'yellowy brown',
               crap => 'browny black');


# BooYah.pm - extract
require 'Foo.pl';

# implicitly
print $::crap{turd};

# or, explicitly
print $main::crap{turd};

# (2) - give Foo.pl a namespace

# Foo.pl - extract
package Foo;
%Foo::crap = (turd => 'yellowy brown',
              crap => 'browny black');

# BooYah.pm - extract
require 'Foo.pl';
print $Foo::crap{turd};

Although I'm a little worried about your question. Shouldn't you be requiring the module from the script and not requiring the script from the module?!?!

Do some research on namespaces, or read perlmod documentation.

cLive ;-)

[bikeNomad]

Actually, you can have packages without using the 'package' keyword, by using fully-qualified names. The following defines things in three different packages (and is loadable as it stands as a module):

sub A::A { }
sub B::B { }
$C::someVar = 123;

[runrig]

That depends. Are you using strict? Is %crap a lexical scoped or package variable? Have you tried just accessing %crap? What problem do you have? How about %BooYah::crap? I think introducing a new global variable from an outside source into your current package namespace is a bad idea, but what do I know?

Update: If BooYah.pm is really a package (declared with 'package BooYah;', then declare %crap with 'use vars' or our. Then you can just directly use %crap in BooYah.pm.