vars::global 0.0.1

vars::global is a Perl module that tries to make global variables a little safer.

SYNOPSIS

# In the place/package where we want to create globals
use vars::global create => qw( $foo @bar %baz );

# Add some more global symbols
vars::global->create(qw( $hello @world %now ));

# Somewhere else, where we need to access those globals
use vars::global qw( $foo @bar %baz );

# Dont try to use globals that do not exist
use vars::global qw( $Foo ); # typo, croaks
use vars::global qw( @inexistent ); # we dont create by default
# use create as above

# You can also import and create new globals
use vars::global qw( $foo %baz ), create => qw( $hey @joe );

# If youre lazy, you can import all the globals defined so far
use vars::global :all;

This module lets you define global variables and gain a slight advantage over blind use of package variables.

The global variables live inside the vars::global package, with the names given by the user. Where the advantage? Its two-fold:

there is an import mechanism that lets you access the global variable without the need to fully qualify its name (i.e. using $foo instead of $vars::global::foo);
the import mechanism ensures that you can import only the global variables that have been explicitly declared so far, which reduces the possibility of a typo.
If you have already "created" the global variable $foo, the import operation is equivalent to do:
*{__PACKAGE__ . ::foo} = $vars::global::foo;
that is, the package variable in the current package is made an alias for the global variable.

The anti-typo check is simply obtained by doing a check before the above import.
Typical usage is as follows:

creation

Early in the module or in the program you create variables prepending the create word, as follows:

use vars::global create => qw( $foo @bar %baz );

access

In the modules where you need to access a given global variable, you can import them very simply:

use vars::global qw( $foo %baz ); # I dont need @bar here ;)

The creation step above automatically imports all the new globals into the current package.