Perl in a Nutshell, 2nd Edition

Exporter

Implements a default import method for other modules to inherit if they don’t want to define their own. If you are writing a module, you can do the following:

package Module;
use Exporter (  );
@ISA = qw(Exporter);

@EXPORT = qw(...);              
@EXPORT_OK = qw(...);           
%EXPORT_TAGS = (tag => [...]);

in which @EXPORT is a list of symbols to export by default, @EXPORT_OK is a list of symbols to export on request, and %EXPORT_TAGS is a hash that defines names for sets of symbols. Names in %EXPORT_TAGS must also appear in @EXPORT or @EXPORT_OK.

Then Perl programs that want to use your module just say:

use Module;                   # Import default symbols
use Module qw(...);           # Import listed symbols
use Module (  );              # Do not import any symbols

The Exporter can handle specialized import lists. An import list is the list of arguments passed to the import method. If the first entry begins with !, :, or /, the list is treated as a series of specifications that add to or delete from the list. A leading ! means delete, rather than add.

Symbol	Meaning
[!] name	This name only
[!]:DEFAULT	All names in @EXPORT
[!]:tag	All names in $EXPORT_TAGS{ tag } anonymous list
[!]/ pattern /	All names in @EXPORT and @EXPORT_OK that match pattern

Exporter’s methods are the following.