There are a couple ways to do this (suprise, suprise).

consider that your file is called 'ab.pm'

BEGIN {
    require ab;
}

$a::variable;
&b::subroutine;
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now, if both packages inherit from Exporter to export variables:

BEGIN {
    require ab;
    import a qw( $var sub );
    import b qw( sub2 sub3);
}
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If you only have one inheriting from Exporter, name the file after it. assuming it's called 'a.pm' and package 'a' inherits from Exporter:

use a qw( $var2 &sub );

BEGIN {
    import b qw( $foo %bar );
}
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