Christopher White
and 1 contributors

NAME

vars::i - Perl pragma to declare and simultaneously initialize global variables.

SYNOPSIS

    use Data::Dumper;
    $Data::Dumper::Deparse = 1;

    use vars::i '$VERSION' => 3.44;
    use vars::i '@BORG' => 6 .. 6;
    use vars::i '%BORD' => 1 .. 10;
    use vars::i '&VERSION' => sub(){rand 20};
    use vars::i '*SOUTH' => *STDOUT;

    BEGIN {
        print SOUTH Dumper [
            $VERSION, \@BORG, \%BORD, \&VERSION
        ];
    }

    use vars::i [ # has the same effect as the 5 use statements above
        '$VERSION' => 3.66,
        '@BORG' => [6 .. 6],
        '%BORD' => {1 .. 10},
        '&VERSION' => sub(){rand 20},
        '*SOUTH' => *STDOUT,
    ];

    print SOUTH Dumper [ $VERSION, \@BORG, \%BORD, \&VERSION ];

DESCRIPTION

For whatever reason, I once had to write something like

    BEGIN {
        use vars '$VERSION';
        $VERSION = 3;
    }

or

    our $VERSION;
    BEGIN { $VERSION = 3; }

and I really didn't like typing that much. With this package, I can say:

    use vars::i '$VERSION' => 3;

and get the same effect.

Also, I like being able to say

    use vars::i '$VERSION' => sprintf("%d.%02d", q$Revision: 1.3 $ =~ /: (\d+)\.(\d+)/);

    use vars::i [
     '$VERSION' => sprintf("%d.%02d", q$Revision: 1.3 $ =~ /: (\d+)\.(\d+)/),
     '$REVISION'=> '$Id: GENERIC.pm,v 1.3 2002/06/02 11:12:38 _ Exp $',
    ];

Like with use vars;, there is no need to fully qualify the variable name. However, you may if you wish.

NOTES

  • Specifying a variable but not a value will succeed silently, and will not create the variable. E.g., use vars::i '$foo'; is a no-op.

    Now, you might expect that use vars::i '$foo'; would behave the same way as use vars '$foo';. That would not be an unreasonable expectation. However, use vars::i qw($foo $bar); has a very different effect than does use vars qw($foo $bar);! In order to avoid subtle errors in the two-parameter case, vars::i also rejects the one-parameter case.

  • Trying to create a special variable is fatal. E.g., use vars::i '$@', 1; will die at compile time.

SEE ALSO

See vars, "our" in perldoc, "Pragmatic Modules" in perlmodlib.

MINIMUM PERL VERSION

This version supports Perl 5.6+. If you are running an earlier Perl, use version 1.01 of this module (PODMASTER/vars-i-1.01).

DEVELOPMENT

This module uses Minilla for release management. When developing, you can use normal prove -l for testing based on the files in lib/. Before submitting a pull request, please:

  • make sure all tests pass under minil test

  • add brief descriptions to the Changes file, under the {{$NEXT}} line.

  • update the .mailmap file to list your PAUSE user ID if you have one, and if your git commits are not under your @cpan.org email. That way you will be properly listed as a contributor in MetaCPAN.

AUTHORS

D.H. <podmaster@cpan.org>

Christopher White <cxw@cpan.org>

Thanks

Thanks to everyone who has worked on vars, which served as the basis for this module.

SUPPORT

Please report any bugs at https://github.com/cxw42/Perl-vars-i/issues.

You can also see the old bugtracker at http://rt.cpan.org/NoAuth/Bugs.html?Dist=vars-i for older bugs.

LICENSE

Copyright (c) 2003--2019 by D.H. aka PodMaster, and contributors. All rights reserved.

This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself.