For a good explanation of the theory, read perldoc perlref. In the meantime: 
sub call_twice {
    my $func = shift;
    &$func("first");
    $func->("second");
}

sub foo { print "foo: @_\n" }
call_twice(\&foo);

call_twice(sub { print "bar: @_\n" });

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    -- Chip Salzenberg, Free-Floating Agent of Chaos

In reply to Re: Passing subroutines as arguments by chip
in thread Passing subroutines as arguments by mvaline

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