NAME

Exporter::LexicalVars - export lexical variables

SYNOPSIS

        BEGIN {
                package MyVars;
                use Exporter::LexicalVars -setup => {
                        '$pi'   => 3.14159,
                        '$foo'  => sub {
                                my $ref = shift;
                                $$ref = "Hello world";
                        },
                };
        };
        
        use Data::Dumper;
        
        my $pi = 3;
        
        {
                use MyVars;
                print Dumper($pi);     # 3.14159
                print Dumper($foo);    # Hello world
        }
        
        print Dumper($pi);        # 3
        
        {
                use MyVars qw( $foo );
                print Dumper($pi);     # 3
                print Dumper($foo);    # Hello world
        }

DESCRIPTION

Exports lexical (my) variables.

In the setup hashref, you can provide either non-reference values to define in the caller's lexical context, or you can provide initializers as coderefs.

Initializers are called with a reference to the variable which has been defined in the caller's lexical context. You can use that reference to not just assign it a value, but potentially mark the variable as read-only, or tie the variable, or whatever.

Lexical scalar, array and hash variables are each supported. In the case of arrays and hashes, providing undef in the setup hashref will initialize them to empty, but otherwise you must initialize them with an initializer coderef; not a non-reference scalar value.

Exporter-style "tags" may also be defined:

        BEGIN {
                package MyVars;
                use Exporter::LexicalVars -setup => {
                        '$pi'     => sub { ... },
                        '$e'      => sub { ... },
                        ':maths'  => [qw( $pi $e )],
                };
        };
        
        use MyVars qw( :maths );
        use MyVars -maths;           # this works too

A tag called :all will be automatically set up for you. If your exporter is called without any arguments, then it will export a tag called :default if it exists, or :all otherwise.

BUGS

Please report any bugs to http://rt.cpan.org/Dist/Display.html?Queue=Exporter-LexicalVars.

SEE ALSO

Exporter::Tiny, Exporter, Sub::Exporter, perldata.

http://www.perlmonks.org/?node_id=1080253.

AUTHOR

Toby Inkster <tobyink@cpan.org>.

COPYRIGHT AND LICENCE

This software is copyright (c) 2014 by Toby Inkster.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

DISCLAIMER OF WARRANTIES

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.