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=head1 NAME
Exporter - module to control namespace manipulations
import - import functions into callers namespace
=head1 SYNOPSYS
package WhatEver;
require Exporter;
@ISA = (Exporter);
@EXPORT = qw(func1, $foo, %tabs);
@EXPORT_OK = qw(sin cos);
...
use Whatever;
use WhatEver 'sin';
=head1 DESCRIPTION
The Exporter module is used by well-behaved Perl modules to
control what they will export into their user's namespace.
The WhatEver module above has placed in its export list
the function C<func1()>, the scalar C<$foo>, and the
hash C<%tabs>. When someone decides to
C<use WhatEver>, they get those identifier grafted
onto their own namespace. That means the user of
package whatever can use the function func1() instead
of fully qualifying it as WhatEver::func1().
You should be careful of such namespace pollution.
Of course, the user of the WhatEver module is free to
use a C<require> instead of a C<use>, which will
preserve the sanctity of their namespace.
In particular, you almost certainly shouldn't
automatically export functions whose names are
already used in the language. For this reason,
the @EXPORT_OK list contains those function which
may be selectively imported, as the sin() function
was above.
See L<perlsub/Overriding builtin functions>.
You can't import names that aren't in either the @EXPORT
or the @EXPORT_OK list.
Remember that these two constructs are identical:
use WhatEver;
BEGIN {
require WhatEver;
import Module;
}
The import() function above is not predefined in the
language. Rather, it's a method in the Exporter module.
A sneaky library writer could conceivably have an import()
method that behaved differently from the standard one, but
that's not very friendly.
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