NAME

Exporter::Easy - Takes the drudgery out of Exporting symbols

SYNOPSIS

In module YourModule.pm:

package YourModule;
use Exporter::Easy (
  OK => [ '$munge', 'frobnicate' ] # symbols to export on request
);

In other files which wish to use YourModule:

use ModuleName qw(frobnicate);      # import listed symbols
frobnicate ($left, $right)          # calls YourModule::frobnicate

DESCRIPTION

The Exporter::Easy module is a wrapper around Exporter. In it's simplest case it allows you to drop the boilerplate code that comes with using Exporter, so

require Exporter;
use base qw( Exporter );
use vars qw( @EXPORT );
@EXPORT = ( 'init' );

becomes

use Exporter::Easy ( EXPORT => [ 'init' ] );

and more complicated situations where you use tags to build lists and more tags become easy, like this

use Exporter (
	EXPORT => [qw( init :base )],
	TAGS => [
		base => [qw( open close )],
		read => [qw( read sysread readline )],
		write => [qw( print write writeline )],
		misc => [qw( select flush )],
		all => [qw( :base :read :write :misc)],
		no_misc => [qw( :all !:misc )],
	],
	OK => [qw( some other stuff )],
);

It sets @EXPORT, @EXPORT_OK, @EXPORT_FAIL and %EXPORT_TAGS in the current package, adds Exporter to that package's @ISA and does a use vars on all the variables mentioned. The rest is handled as normal by Exporter.

HOW TO USE IT

Put

use Exporter::Easy ( KEY => value, ...);

In your package. Arguments are passes as key-value pairs, the following keys are available

EXPORT

The value should be a reference to a list of symbol names and tags. Any tags will be expanded and the resulting list of symbol names will be placed in the @EXPORT array in your package. The tag created by the ALL key is not available at this stage.

FAIL

The value should be a reference to a list of symbol names and tags. The tags will be expanded and the resulting list of symbol names will be placed in the @EXPORT_FAIL array in your package. They will also be removed from the @EXPORT_OK list.

TAGS

The value should be a reference to a list that goes like (TAG_NAME, TAG_VALUE, TAG_NAME, TAG_VALUE, ...), where TAG_NAME is a string and TAG_VALUE is a reference to an array of symbols and tags. For example

TAGS => [
  file => [ 'open', 'close', 'read', 'write'],
  string => [ 'length', 'substr', 'chomp' ],
  hash => [ 'keys', 'values', 'each' ],
  all => [ ':file', ':string', ':hash' ],
  some => [':all', '!open', ':hash'],
]

This is used to fill the %EXPORT_TAGS in your package. You can build tags from other tags - in the example above the tag all will contain all the symbols from file, string and hash. You can also subtract symbols and tags - in the example above, some contains the symbols from all but with open removed and all the symbols from hash removed.

The rule is that any symbol starting with a ':' is taken to be a tag which has been defined previously (if it's not defined you'll get an error). If a symbol is preceded by a '!' it will be subtracted from the list, otherwise it is added.

If you try to redefine a tag you will also get an error.

All the symbols which occur while building the tags are automatically added your package's @EXPORT_OK array.

OK

The value should be a reference to a list of symbols and tags (which will be exapanded). These symbols will be added to the @EXPORT_OK array in your package. Using OK and and OK_ONLY together will give an error.

OK_ONLY

The value should be a reference to a list of symbols and tags (which will be exapanded). The @EXPORT_OK array in your package will contains only these symbols.. This totally overrides the automatic population of this array. If you just want to add some symbols to the list that Exporter::Easy has automatically built then you should use OK instead. Using OK_ONLY and OK together will give an error.

ALL

The value should be the name of tag that doesn't yet exist. This tag will contain a list of all symbols which can be exported.

ISA

If you set this to 0 then Exporter will not be added to your @ISA list.

VARS

If this is set to 1 or not provided then all $, @ and % variables mentioned previously will be available to use in your package as if you had done a use vars on them. If it's set to a reference to a list of symbols and tags then only those symbols will be available. If it's set to 0 then you'll have to do your own use vars in your package.

DETAILED EXPLANATION

Keeps changing too much once it stops changing so much, I'll write this.

SEE ALSO

For details on what all these arrays and hashes actually do, see the Exporter documentation.

AUTHOR

Written by Fergal Daly <fergal@esatclear.ie>.

LICENSE

Under the same license as Perl itself