Exporter - provide inport/export controls for Perl modules


use Module; use Module qw(name1 name2 :tag /pattern/ !name);


If the first entry in an import list begins with !, : or / then the list is treated as a series of specifications which either add to or delete from the list of names to import. They are processed left to right. Specifications are in the form:

[!]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 which match

A leading ! indicates that matching names should be deleted from the list of names to import. If the first specification is a deletion it is treated as though preceded by :DEFAULT. If you just want to import extra names in addition to the default set you will still need to include :DEFAULT explicitly.

e.g., Module.pm defines:

@EXPORT = qw(A1 A2 A3 A4 A5); @EXPORT_OK = qw(B1 B2 B3 B4 B5); %EXPORT_TAGS = (T1 => [qw(A1 A2 B1 B2)], T2 => [qw(A1 A2 B3 B4)]); Note that you cannot use tags in @EXPORT or @EXPORT_OK. Names in EXPORT_TAGS must also appear in @EXPORT or @EXPORT_OK.

Application says:

use Module qw(:DEFAULT :T2 !B3 A3); use Socket qw(!/^[AP]F_/ !SOMAXCONN !SOL_SOCKET); use POSIX qw(/^S_/ acos asin atan /^E/ !/^EXIT/);

You can set $Exporter::Verbose=1; to see how the specifications are being processed and what is actually being imported into modules.

Module Version Checking

The Exporter module will convert an attempt to import a number from a module into a call to $module_name->require_version($value). This can be used to validate that the version of the module being used is greater than or equal to the required version.

The Exporter module supplies a default require_version method which checks the value of $VERSION in the exporting module.