Hello nysus,

use Foo -bar; is essentially

BEGIN {
    require Foo;
    Foo->import("-bar");
};
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You can define your own import sub, just like follows:

package Foo;

use strict;
use warnings;

sub import {
    warn "@_";
};

1;
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Furthermore, you can use Exporter:

package Foo;

use strict;
use warnings;

use parent qw(Exporter);
our @EXPORT_OK = qw(quux);

sub import {
    warn "@_";
    if (grep { /-bar/ } @_) {
        __PACKAGE__->export_to_level(1, undef, "quux");
    };
};

sub quux {
    return 42;
};

1;
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And this will suddenly export quux to the calling package, despite having "-bar" in the use statement.

No magic there, just a lot, A LOT of silent conventions.