This answer is correct, but I would also add that it is possible to store the subroutine name rather than as code reference. For example:

sub test {
    print "Hello world!\n";
}

my $subroutine = "test";
&{$subroutine};
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The caveat to this approach is that it breaks strict refs unless the $subroutine scalar is evaluated (eg. eval $subroutine).

 

Update - Check out the nifty example from broquaint in this thread here

 

perl -e 'print+unpack("N",pack("B32","00000000000000000000000111010010")),"\n"'