Programming Perl, 4th Edition

Unloading Modules

The opposite of use is no. Instead of calling import, it calls unimport. That method can do whatever it likes. The syntax is the same:

no MODULE;
no MODULE LIST;
no MODULE VERSION;
no MODULE VERSION LIST;

You may only want some symbols available for a short time. For instance, the Moose module, an object system built on top of Perl’s built-in features, imports many convenience methods. The has method declares attributes, but once you are done with those names, they don’t need to stick around. At the end of the section that needs them, you can unimport them with no:

package Person;
use Moose;

has "first_name" => (is => "rw", isa => "Str");
has "last_name"  => (is => "rw", isa => "Str");

sub full_name {
    my $self = shift;
    $self–>first_name . " " . $self–>last_name
}

no Moose; # keywords are removed from the Person package

To temporarily turn off a strict feature, unimport the feature that’s in the way. Use the smallest scope possible so you don’t miss other problems:

my $value = do {
  no strict "refs";

  ${ "${class}::name}" }; # symbolic reference
};

Similarly, you might need to temporarily turn off a type of warning, so you unimport that type of warning:

use warnings;
{
    no warnings 'redefine';
    local *badger = sub { ... };
    ...;
}